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HP 8673H User's Manual

1. Manual Sweep Mode 3 86 Marker Frequency Sweep 3 90 Master Slave Sweep 3 94 Messages 3 97 Multiplier Mode 3 99 Offset Frequency 3 102 Power Meter Automatic Level Control w 3 105 Pulse Modulation a 3 110 Range Output Level 3 113 Recall and Store Registers 3 116 RF Output On Off 3 119 Single Sweep Mode 3 121 Start Frequency Sweep 3 125 Status Byte and Polling 3 130 Steps Sweep 3 137 Step Size Sweep 1 3 140 Stop Frequency Sweep 3 143 System Automatic Level Control a 3 148 Vernier Output Level z 3 151 Section 4 PERFORMANCE TESTS Page Abbreviated Performance Test Calibration Cycle Performance Test Record Equipment Required Test Procedures Abbreviated Performance Tests e Al 4 2 Turn On Checks Frequency Range and Resolution Test ve 43 Output Level and Flatness Tests 45 Level Accuracy Tests Pulse Modulation Test AM Accuracy Tests Extemal FM Accuracy and Meter Accuracy Frequency Range and Resolution Test Internal Time Base Aging Rate 4 8 4 11 4 15 ALT 4 25 431 Frequency Switching Time Test Single Sideband Phase Noise Test 4 39 Harmonics Subharmonics amp Multiples Tests 4 44 Non Harmonically Related Spurious Signals Tests 4 46 Power Line Related Spurious Signals Tests 06 4 48 Output Level and Flatness Tests Ab
2. The Signal Generator responds to a Serial Poll Enable SPE bus com mand by sending an 8 bit byte when addressed to talk If the instrument is holding the SRQ control line true issuing the Require Service message bit 7 RQS bit in the Status Byte and the bit representing the condition causing the Require Service message to be issued will both be true The bits in the Status Byte are latched but can be cleared upon receiving the Clear Status CS program code executing the Output Status function or executing a serial poll while the SRQ control line is held true 3 34 HP 8673H Operation Table 3 3 Message Reference Table 2 of 2 HP IB Appli R esponse i Status Yes j The Signal Generator responds to a Parallel Poll Enable PPE bus PPE PPI Bit command by sending a bit on a controller selected HP IB data line PPD PPU The Signal Generator stops talking and listening T5 TEQ LE LEO Commands Control lines and Interface Functions are defined in IEEE Std 488 1978 Knowledge of these may not be necessary if your controller s manual describes programming in terms of the twelve HP IB Messages shown in the left column Related Commands and Controls PPC Complete HP IB capability as defined in IEEE Std 488 and ANSI Std MC1 1 is SH1 AH1 T5 TEO L3 LEO SR1 RL1 PP1 DC1 DT1 and CO 3 27 Addressing The Signal Generator interprets the byte on the eight HP IB data lines as an a
3. 6 On both instruments set the number of sweep steps to the desired value For constant offsets both instruments must be set for the same number of steps 7 On the Slave unit select a frequency offset by resetting the Slave center frequency to the desired offset from the Master center frequency 8 Press and hold the SWEEP START frequency key on the Slave unit The frequency should be different from the Master unit start frequency by the desired offset The SWEEP STOP frequency should also be offset by the same amount 9 To operate Master Slave sweep in AUTO sweep mode press AUTO on the Master unit The Master unit will begin to sweep and the Slave unit will track it The Slave unit will enter Slave mode when sweep is selected on the Master unit When the Signal Generator is in Slave mode the MANUAL and SINGLE indicators will be illuminated 10 To operate Master Slave in MANUAL sweep mode Press MANUAL on the Master unit Use the TUNE knob on the Master unit to tune both Master and Slave units The Slave unit will enter Slave mode when sweep is selected on the Master unit When the Signal Generator is in Slave mode the MANUAL and SINGLE indicators will be illuminated HP 8673H Local Procedure cont d Remote Procedure Example Comments Operation Detailed Operating Instructions Master Slave Sweep cont d 11 To operate Master Slave in SINGLE mode Press SINGLE on the Master unit once to arm the sweep Press it a
4. To end the use of the offset function press SHIFT OFFSET OFFSET MULTIPLIER To accommodate an external x2 multiplier press SHIFT MULT X FREQ EOE The displayed frequency will be twice the signal Generator s actual output frequency Note When in multiplier mode enter frequencies according to desired output For example to obtain 30 GHz enter 30 GHz into the keyboard The Signal Generator will output 15 GHz into the x2 frequency multiplier To end the use of the multiplier function press SHIFT MULT X FREQ JO G3 ltiplied OR es oF i hare depre Ifunct FT ke inctic itainir dith tF Figu ion o igure Operation FRONT PANEL FEATURES Message key illuminat indicate input errors failures respectively L x key displays error ma Amplitude frequency and pulse modu frequency display lation of microwave carrier via external modulating signals Calibrated metering of output level vernier AM depth and FM deviation Leveling of output power by internal external diode external power meter or system references BE7SNEYNTHESIZED SIGNAL GENERATOR 2 0 Output level settable from 13 to 100 dBm Resolution is 0 1 dB under HP IB control A The RF Output is protected SA againt reverse power applications up to 1W However for best protection of internal circuitry do not apply any reverse power Output level controlled in 10 dB
5. 25 Hz to 25 kHz Deviation to 99 kHz Accuracy 2 at 1 kHz Bandwidth 100 MHz Vertical Sensitivity 5 mV div Vertical Input ac de or 50Q de coupled External Trigger Capability Delayed Sweep Capability One Shot Digitizer Power Meter Automated adjustment programs require specific test HP 436A P A equipment Therefore no substitute is recommended Power Sensor Frequency Range 2 to 18 GHz HP 8481A Input Impedance 50Q California Instruments SWR lt 1 25 501TC 800T 3 Oscilloscope HP 1980B 19860A Must be compatible with power meter Power Source Variable Range 60 Vac to 240 Vac Frequency AC Frequency 48 to 400 Hz Accuracy 2 Hz 1 15 ms General Information HP 8673H Table 1 3 Recommended Test Equipment 3 of 3 Recommended Instrument Critical Specifications Model Noise Figure lt 5 dBm amplifier and will satisfy Preamp Power Amp Preamp HP 8447D Impedance 50Q both requirements Frequency 100 kHz to 1 3 GHz Gain 26 2 dB Output Power gt 7 dBm Noise Figure lt 8 5 dB Impedance 509 Pulse Generator Rate 10 Hz to 4 MHz HP 8116A or HP 8013B Rise and Fall Times lt 5 ns Output Impedance 50Q Output Level 0 to 3 5 V Pulse Width 80 ns to 2 us Signal Generator Output Level 5 to 20 dBm at 240 MHz HP 8340B or HP 8640B A Signature Analyzer Because signatures depend upon the model selected only HP S0
6. 4i 42 Press RCL 0 Set Output Level RANGE to 0 dB and Output Level VERNIER to 0 dBm Press the PULSE COMPL key The UNLEVELED status annunciator should remain off 43 Press the PULSE NORM key Verify that the UNLEVELED status annunciator turns on Press PULSE OFF and verify that UNLEVELED status annunciator now turns off 44 Connect the pulse generator and oscilloscope to the Signal Generator as shown in Figure 3 10 T YNT GRRL GENERATOR OSCILLOSCOPE aS Figure 3 10 Pulse Modulation Functional Check Setup 45 Set the oscilloscope to 50Q input impedance and extemal horizontal trigger 46 Set the pulse generator for a 150 ns pulse width at one pulse per microsecond 1 MHz 3 23 Operation HP 8673H OPERATOR S CHECKS Basic Functional Checks cont d Procedure cont d 47 48 49 50 On the pulse generator adjust the pulse amplitude for a pulse height of approximately 3 V peak With PULSE OFF selected CW mode note the indicated power level on the Signal Generator s meter should be 0 dBm Press PULSE NORM and PULSE COMPL keys while observing any change in indicated output power level Indicated level should not vary more than 1 dB from the level referenced with pulse off CW mode While in PULSE NORM mode slowly reduce the pulse width from 150 ns to 50 ns The UNLEVELED annunciator should come on as 100 ns pulse width is approached It should remain on down to at
7. 8 LINE Switch Applies power to the Signal 3 12 Generator when set to the ON position Power is supplied to the reference oscillator oven and the battery charger circuit in the STBY and ON positions TUNE Knob Changes the CW frequency by the value set with FREQ INCR The knob is enabled by the ON OFF key The knob also serves as a manual sweep made control HP 8673H FREQ INCREMENT W and M Keys Decreases or increases the CW frequency in steps the increment size is set with the FREQ INCR key Holding either key down causes the frequency to continuously change These keys also serve as a manual sweep mode control In manual sweep the increment size is equal to the sweep step size Figure 3 4 Frequency Control Features and LINE Switch 2 of 2 HP 8673H Operation SWEEP FREQ 1 STRT MULT Key Normal operation STRT Used as a prefix to the Data and Units keys to set the beginning frequency of a sweep Pressing this key displays the present START value in the FREQUENCY MHz display for as long as the key is depressed Shifted function MULT Used as a prefix to the Data and Units keys Invokes the multiplier mode of operation and allows entry of the frequency multiplication factor The entered multiplication factor affects all frequencies that is markers increments FM deviation CW sweep and center frequencies The multiplication effect on FM deviation is not indicated on the FM mete
8. HP 8673H Detailed Operating Instructions Remote Procedure Example 3 144 Stop Frequency Sweep cont d The Signal Generator accepts any sweep stop frequency within its specified frequency range Above 6 6 GHz the programmed frequency may be rounded by the Signal Generator to be compatible with the 2 or 3 kHz resolution at the programmed frequency see comments The format of the remote programming follows the front panel key sequence To program the sweep stop frequency the program code FB is sent followed by the desired frequency and the units GZ MZ KZ or HZ If setting the new start frequency causes a change of the CW frequency normally the case the SOURCE SETTLED bit of the status byte can be monitored to determine when the new frequency has settled Once this bit is set the NOT PHASE LOCKED bit in the extended status byte may be checked to ensure that the instrument is working correctly The NOT PHASE LOCKED bit is not valid until after the SOURCE SETTLED bit has been set The current sweep stop frequency can be read by the controller using the output active program code suffix To read the stop frequency send the program codes FBOA and then read the stop frequency The Signal Generator will send the frequency in fundamental Hz units If the frequency is read as a string the format will be the program code FB followed by the sweep stop frequency in Hz and then the units terminator Hz To set the sweep s
9. Internal Switch Setting To change the internal HP IB address switch proceed as follows Operating voltage is shown in module window SELECTION OF OPERATING VOLTAGE 1 Open cover door pull the FUSE PULL lever and rotate to left Remove the fuse 2 Remove the Line Voltage Selection Card Position the card so the line voltage appears at top left corner Push the card Internal switch settings should be changed only by service trained persons who are firmly into the slot 3 Rotate the FUSE PULL lever to its normal position Insert a fuse of the correct value in the holder Close the caver aware of the potential shock hazard of working on an instrument with protective covers removed doar WARNING To avoid the possibility of hazardous electri cal shock do net operate this instrument at line voltages greater than 126 5 Vac with line frequencies greater than 66 Hz leakage cur rents at these line settings may exceed 3 5 mA To avoid hazardous electrical shock the line mains power cable should be disconnected before attempting to change the internal HP IB address switch settings Figure 2 1 Line Voltage and Fuse Selection 220 240V OPERATION 100 120V OPERATION 220 240V OPERATION 220 240V OPERATION PLUG SEV 1011 1953 24507 TYPE 12 CABLE HP 8120 2104 PLUG NZSS 198 AS C112 CABLE HP 8120 1369 PLUG NEMA 5 15P CABLE 8120 13
10. 3 36 Bench Operation 2 4 O g z utput Level 3 36 Rack Mounting 2 Data Messages 3 36 Storage gnd Shipment 24 Receiving Data Messages 3 36 Environment Sending the Data Message 3 37 PACKAGING 5 ar sce dinavecedecegcdanenywaesnegseuss Receiving the Clear Message 3039 Section 3 Receiving the Trigger Message 3 40 OPERATION Receiving the Remote Message we 3 40 Receiving the Local Message 3 40 Introduction ae 3 1 Receiving the Local Lockout Message 3 40 System Compatibility 3 1 Receiving the Clear Lockout Set Local Message 3 40 Operating Characteristics 3 1 Receiving the Pass Control Message 3 40 Local Operation 3 1 Sending the Require Service Message 3 40 Remote Operation 3 1 Sending the Status Byte Message 3 41 Operator s Checks ve Bel Clearing the Status Byte wo 3 41 Operator s Maintenance a 3 1 Sending the Status Bit Message we 3 41 Battery Replacement 3 1 Receiving the Abort Message wae 3 42 General Instructions 3 5 Detailed Operating Instructions a 3 45 Turm On 35 Amplitude Modulation 3 45 Contents HP 8673H CONTENTS cont d Page Auto Peak 3 48 Auto Sweep Mode 3 50 Center Frequency Sweep 3 54 Delta Frequency Sweep 3 58 3 62 Diode Automatic Level Control ee Dwell Time Sweep 3 66 Frequency CW 3 68 Frequency Increment and Tuning 3 74 Frequency Modulation 006 3 80 Internal Automatic Level Control 3 83
11. R pee J Level Accuracy dB _ Output Level dBm 2 4 6 8 10 12 1416 Output Frequency GHz Typical HP 8673H output level accuracy at 0 70 and 100 dBm level settings PULSE MODULATION Pulse Width Pulse widths less than 100 ns are possible with degraded peak power level accuracy relative to CW Pulse Input Normal Mode gt 3V on lt 0 5V off Complement Mode lt 0 5V on gt 3V off Impedance 50 ohms nominal Damage Level More positive than 6 Vpk from lt 50 ohm source or more negative than 0 5 Vpk from 50 ohm source Pulse Width Compression lt 35 ns Maximum Delay Time 150 ns Video Feedthrough lt 50 dBc General Information Characteristics 2 of 2 AMPLITUDE MODULATION Frequency Response Relative to a 1 kHz Rate 0 25 dB 100 Hz 10 kHz Distortion Depth Percentage 20 40 60 Rate kHz fe 2 0 to lt 18 0 GHz Carrier Level 0 dBm Typical HP 8673H AM distortion versus modulation rate and depth FREQUENCY MODULATION Rates 3 dB bandwidth 100 Hz to 10 MHz 30 and 100 kHz V ranges 1 kHz to 10 MHz 300 kHz V and 1 3 and 10 MHz V ranges FM Distortion Percentage 50 75 Modulation Rate kHz Typical HP 8673H FM Distortion versus modulation rate General information HP 8673H Table 1 3 Recommended Test Equipment 1 of 3 i Recommended Critical Specifications Model Hone E HP 8
12. Recall and Store Registers conta RF OUTPUT to ON ALC mode to INT RANGE to 70 dB 0 dB for Options 001 and 005 AUTO PEAK to ON MTR scale to LVL AM FM and PULSE modulation to OFF FREQUENCY to 9000 000 MHz FREQ INCR to 1 000 MHz START to 8000 000 MHz STOP to 10000 000 MHz AF to 2000 000 MHz MKRs disabled initialized to 7 8 9 10 and 11 GHz SWEEP MODE to OFF STEP to 100 steps 20 000 MHz DWELL to 20 ms TUNE knob to ON An alternate preset provides a different set of conditions more suitable for some applications The alternate preset conditions selected with RCL and Backspace are given below RF OUTPUT to ON OFFSET frequency to 0 MULTIPLIER and ALC mode unchanged RANGE to 70 dB 0 dB for Options 001 and 005 AUTO PEAK to ON MTR scale to LVL AM FM and PULSE modulation to OFF FREQUENCY to 11 000 000 MHz X Multiplier Option 212 FREQUENCY to 14 000 000 MHz X Multiplier Option 618 FREQ INCR to 1 000 MHz X Multiplier START to 10 000 000 MHz X Multiplier Option 212 START to 13 000 000 MHz X Multiplier Option 618 STOP to 12 000 000 MHz X Multiplier Option 212 STOP to 15 000 000 MHz X Multiplier Option 618 AF to 2000 000 MHz X Multiplier MKRs disabled initialized to 7 8 9 10 and 11 GHz X Multiplier SWEEP MODE to OFF STEP to 100 steps 20 000 MHz X Multiplier DWELL to 20 ms TUNE knob to ON The following errors apply to storing or recalling instrument state registers 04 Cannot s
13. cont d Rates Sensitivity AM per Vpk Indicated Meter Accuracy Accuracy Relative to Extemal AM Input Level Incidental Phase Modulation 100 Hz to 10 kHz rates 30 depth Incidental FM FREQUENCY MODULATION Frequency Response Relative to 100 kHz rate 100 Hz to 3 MHz 3 kHz to 3 MHz Maximum Peak Deviation Sensitivity peak deviation per Vpk Indicated Meter Accuracy Accuracy Relative to External FM Input Level Incidental AM DIGITAL SWEEP Sweep Function Sweep Modes 20 Hz to 100 kHz S pulse width x PRF x 4 kHz 30 V and 100 V depending on range 7 of reading 3 of range 4 of reading 2 of range lt 0 4 radians lt 0 8 radians lt 1 2 radians Incidental phase modulation x fmod 42dB 22dB The smaller of 10 MHz or fmod x 5 The smaller of 10 MHz or fod x 10 The smaller of 10 MHz or fod x 15 Maximum input 1 Vpk into SOQ nominal 12 of reading 3 of range 7 of reading 3 of range lt 5 Rates Start Stop or Center Frequency AF Span Sweep Manual Auto Single 3 dB bandwidth 30 depth Pulse Modulation off With Pulse Modulation on Maximum input 1 Vpk into 600Q nominal AM depth is linearly controlled by varying input level between 0 and 1 V peak 100 Hz to 10 kHz rates 100 Hz to 10 kHz rates 2 0 to 6 6 GHz gt 6 6 to 12 3 GHz gt 12 3 to 18 0 GHz 30 and 100 kHz V ranges 300 kHz V and 1 3 and 10 MHz V ranges 2 0 to 6 6 GHz gt 6 6 to
14. frequency FM and pulse Each type tequires an external drive signal Front panel keys select the maximum of AM depth FM deviation in MHz and normal NORM or complement COMPL pulse mode For AM and FM a 1 Vpk signal develops full scale modulation Modulation varies linearly with the input signal For pulse modulation a TTL level positive true pulse turns RF on in normal mode A TTL level negative true pulse turns RF on in complement mode MESSAGES Entry errors hardware malfunctions and other significant conditions are indicated by the lighted MESSAGE key MESSAGE Press e to read the two digit code in the FREQUENCY MHz display The codes are explained in Table 3 8 and on the operating information pull out card 3 3 Operation HP 8673H SWEEP 3 4 Values for SWEEP FREQ START STOP AF and MKR and SWEEP RATE STEP and DWELL are entered in a Function Data Units format SWEEP FREQ The SWEEP FREQ keys set the span of the sweep that is the range that the sweep covers The sweep span can be set with either the START and STOP keys or with the FREQUENCY and AF keys For example to set a sweep span of 2 GHz with a start frequency of 7 GHz and a stop frequency of 9 GHz press a FUNCTION gt DATA w gt UNITS me ae FUNCTIONS yo DATA pe UNITS me FREQUENCY crz C SWEEP RATE During a sweep the Signal Generator changes frequency in discrete steps Sweep rate is determined by the number of steps and the
15. Front Handle Kit part number is 5061 9689 Option 908 Rack Flange Kit The Signal Generator can be solidly mounted to the instrument rack without handles using the flange kit The Rack Flange Kit part number is 5061 9677 Option 908 Rack Flange and Front Handle Combination Kit This is a unique part which combines both functions It is not simply a front handle kit and a rack flange kit packaged together The Rack Flange and Front Panel Combination Kit part number is 5061 9683 1 9 Miscellaneous Options Option 915 Provides a service manual Option 916 Provides an extra operating manual Option W30 Provides two additional years of return to HP service The first year of normal warranty is combined with this extended service to provide three full continuous years of HP service All repairs of failures due to defects in materials or workmanship are covered under this extended service Repair services do not include routine preventative maintenance or periodic calibrations of the instrument fir 5073n 1 10 ACCESSORIES SUPPLIED The accessories supplied with the Signal Generator are shown in Figure 1 1 a The line power cable is supplied in several configurations depending on the destination of the original shipment Refer to Power Cables in Section 2 of this manual b An additional fuse is shipped only with instruments that are factory configured for 100 120 Vac operation This fuse has a 2A rating for reconfigurin
16. Inc 161 East Industry Court Deer Park NY 11729 Tel 516 242 1100 TWX 510 227 6083 3 California Instruments 5150 Convoy Street San Diego CA 92111 Tel 714 279 8620 1 16 HP 8673H General Information SPECIAL INTERCONNECT CABLE Figure 1 2 Special Interconnect Cable Table 1 4 Abbreviated Performance Test Recommended Test Equipment 1 of 2 Recommended instrument Critical Specifications Model Attenuator Fixed 6 dB Range de to 18 GHz HP 84918 Option 006 Accuracy 0 6 dB SWR lt 1 6 Attenuator Fixed 10 dB Range dc to 18 GHz HP 8491B Option 010 two needed Accuracy 0 6 dB SWR lt 1 3 Attenuator Fixed 20 dB Range de to 18 GHz HP 8491B Option 020 Accuracy 1 0 dB SWR lt 1 6 Audio Analyzer Frequency Range 20 Hz to 100 kHz HP 8903B Accuracy 4 of full scale Audio Source Frequency Range 20 Hz to 100 kHz HP 8903B Output Level 1 mV to 6 V open circuit Flatness 2 5 Cable Semi Rigid 8 length SMA m m Locally Fabricated Digital Voltmeter Resolution 1 mV HP 3456A or HP 3455A Range 212 to 707 Vrms Frequency Response 100 Hz to 100 kHz Range 10 MHz to 18 GHz HP 5340A or HP 5343A Resolution 100 Hz 10 MHz Frequency Standard Output 2 1 Vrms Local Oscillator Range 2 GHz to 18 GHz HP 8340B Level gt 5 dBm Mixer Response 1 to 18 GHz RHG DM1 18 VSWR LO 2 5 1 VSWR RF lt 4 0 1 Measuring Receiver Frequency Range 150 to 990 MHz HP 8
17. International Standards Organization members WARRANTY This Hewlett Packard instrument product is warranted against defects in material and workmanship for a period of one year from date of shipment During the warranty period Hewlett Packard Company will at its option either repair or replace products which prove to be defective For warranty service or repair this product must be returned to a service facility desig nated by HP Buyer shall prepay shipping charges to HP and HP shall pay shipping charges to return the product to Buyer However Buyer shall pay all shipping charges duties and taxes for products returned to HP from another country HP warrants that its software and firmware designated by HP for use with an instrument will execute its programming instructions when properly installed on that instrument HP does not warrant that the operation of the instrument or software or firmware will be uninterrupted or error free LIMITATION OF WARRANTY The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer Buyer supplied software or interfacing unauthorized modification or misuse operation outside of the environmental specifications for the product or improper site preparation or maintenance NO OTHER WARRANTY IS EXPRESSED OR IMPLIED HP SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE EXCLUSIVE REMEDIES THE REMED
18. The Signal Generator generates a de voltage that is proportional to the CW RF frequency This voltage is available at the rear panel FREQ REF connector Sensitivity is selectable from 0 5 V GHz or 1 V GHz The sensitivity is selected using C1 of switch 2 on A2A7 the VO assembly 2 11 Operating Environment The operating environment should be within the following limitations Temperate nise nonesa 0 to 55 C Humidity a ss65 os cae ced orias lt 95 relative Altitudes susare lt 4570 metres 15 000 feet Specifications for harmonically related spurious sig nals RF output pulse and amplitude modulation ap ply only over the temperature range of 15 to 35 C 2 12 Bench Operation The instrument cabinet has plastic feet and foldaway tilt stands for convenience in bench operation The plastic feet are shaped to ensure self aligning of the instru ments when stacked The tilt stands raise the front of the instrument for easier viewing of the front panel 2 13 Rack Mounting The Signal Generator weighs 29 kg 64 Ibs therefore extreme care must be exercised when lifting to avoid personal injury To avoid personal injury and equipment damage use equipment slides when rack mounting the instrument 2 4 HP 8673H Rack mounting information is provided with the rack mounting kits If the kits were not ordered with the instrument as options they may be ordered through the nearest Hewlett Packard office Refer to the
19. This corresponds to the data output shown in the FREQUENCY MHz display Local Lockout and Clear Lockout Set Local Messages Note This check determines if the Signal Generator properly receives the Local Lockout message disabling the LOCAL key The check also determines if the Clear Lockout Set Local message is properly received and executed by the Signal Generator This check assumes that the Signal Generator is in the remote mode Description Series 200 300 200 300 HP 85B HP 85B BASIC Send the Local Lockout message LOCAL LOCKOUT 7 LOCAL LOCKOUT 7 Operator s Check that the Signal Generators RMT annunciator ison Press the Signal Generator s Response LOCAL key The RMT annunciator should remain on Send the Clear Lockout Set Local message Operator s Check that the Signal Generator s RMT annunciator is off but the TLK annunciator is still on Response Return the Signal Generator to remote REMOTE 719 REMOTE 719 mode if the remaining checks in this section are to be performed Operator s Check that the Signal Generator s RMT and LSN annunciators are on Response 3 27 Operation HP 8673H OPERATOR S CHECKS HP IB Functional Checks cont d Clear Message Note This check determines if the Signal Generator properly responds to the Clear message This check assumes that the Signal Generator is in the remote mode Description Serles 200 300 HP 85B BASIC Send a Data message that tums AUTO OUTP
20. cleared after the service request Failure to clear the message will result in additional service requests generated with each program string To clear the message output the program code MG and then read the message Once the message is read or the MESSAGE key on the front panel is pressed the message will be cleared The status byte and the extended status byte are both binary values When entering the status byte and extended status byte into the controller use a formatted statement to input the values as binary If a formatted statement is not used the controller may recognize a value of twelve as a carriage return and terminate the entry This can occur when the SOURCE SETTLED BIT and the CHANGE IN EXTENDED STATUS bits are the only bits set in the status byte In addition the controller should be instructed not to accept the line feed character decimal 12 as an early termination of the data transfer The correct format for the HP 9000 Series 200 and 300 or the HP 85 controllers is ENTER 719 USING B B S1 S2 The following programs are written in BASIC for HP 9000 Series 200 or 300 controllers The program below is used to test for the SOURCE SETTLED bit after a frequency or level change Since the SOURCE SETTLED bit is not set for some program codes a timeout is provided to terminate the subroutine 3 135 Operation HP 8673H Detailed Operating Instructions Programming 10 Example 20 cont d 30 Status Byte and Pollin
21. frequency 2 Enter the desired frequency using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue entering the correct digits until the frequency displayed in the FREQUENCY MHz display is correct 3 Press the appropriate units key The frequency can be entered in GHz MHz or kHz Once the units key is pressed the displayed frequency will be adjusted to display in MHz units and the sweep delta frequency will be set The sweep delta frequency will continue to be displayed until the units key is released The frequency displayed after releasing the units key may not be the same frequency displayed before the entry If sweep mode is off the displayed frequency will be the CW frequency no change If auto sweep is on the sweep will be reset and then continue using the new delta frequency If single sweep is on the sweep will be reset and the sweep will remain armed at the new start frequency If manual sweep is on the sweep frequency will be reset to the new start frequency To check the current sweep delta frequency press and hold the SWEEP FREQ AF key The FREQUENCY MHz display will display the sweep delta frequency as long as the key is held When any sweep mode is turned off the CW frequency will be set to halfway between the start and stop frequencies equal to the sweep center frequency HP 8673H Remote Procedure Example Program Cod
22. frequency of the sweep Tuning the frequency during single or auto sweep mode changes the sweep center frequency in steps equal to the frequency increment In auto sweep mode the sweep will continue about the new center frequency In single sweep mode the sweep will reset to the new start frequency and remain armed In manual sweep mode tuning the frequency has the effect of changing the RF output frequency by the sweep step size The frequency increment is not used during manual sweep mode To check the current frequency increment press and hold the FREQ INCR key The FREQUENCY MHz display will display the frequency increment as long as the key is held The Signal Generator accepts frequency increments between 1 kHz and the maximum Signal Generator frequency 12 4 GHz Option 212 or 18 0 GHz Option 618 The minimum tuning increment is dependent on the RF output frequency For output frequencies less than 6 6 GHz the minimum tuning increment is 1 kHz Above 6 6 GHz the minimum tuning increment is 2 kHz 6 6 to 12 3 GHz or 3 kHz 12 3 to 18 0 GHz Although the frequency increment can be set to 1 kHz the actual tuning increment used will be determined by the RF output frequency see comments The format of the remote programming follows the front panel key sequence To program the frequency increment the program code FI or FN is sent followed by the desired frequency increment and the units GZ MZ KZ or HZ The CW frequency is inc
23. 52 dBc 10 Hz offset from carrier 64 dBc 100 Hz offset from carrier 72 dBc 1 kHz offset from carrier 80 dBc 10 kHz offset from carrier 104 dBc 100 kHz offset from carrier gt 12 3 18 0 GHz 48 dBc 10 Hz offset from carrier 60 dBc 100 Hz offset from carrier 68 dBc 1 kHz offset from carrier 76 dBc 10 kHz offset from carrier 100 dBe 100 kHz offset from carrier Harmonics lt 40 dBc 2 0 to 18 0 GHz output level meter readings lt 0 dBm on 0 dB range and below 1 6 HP 8673H General Information Table 1 1 Specifications 2 of 6 Electrical Characteristics Performance Limits Conditions SPECTRAL PURITY cont d lt 25 dBc Subharmonics and Multiples thereof 2 0 to 18 0 GHz Spurious Signals Nonharmonicaily Related CW and AM modes 2 0 to 6 6 GHz gt 6 6 to 12 3 GHz gt 12 3 to 18 0 GHz lt 70 dBe lt 64 dBc lt 60 dBc Power line related and fan rotation related within 5 Hz below line frequencies and multiples thereof Option 003 is not specified See Table 1 2 for supplemental characteristics for Option 003 2 0 6 6 GHz lt 300 Hz offset from carrier 300 Hz to 1 kHz offset from carrier gt 1 kHz offset from carrier lt 300 Hz offset from carrier 300 Hz to 1 kHz offset from carrier gt I kHz offset from carrier lt 300 Hz offset from carrier 300 Hz to 1 kHz offset from carrier gt 1 kHz o
24. Data and ms keys to set the time interval between sweep steps Pressing this key displays the present dwell time value in the FREQUENCY MHz display for as long as the key is depressed The allowable values for dwell time range from 1 to 255 ms SWEEP W sE pen ae om carr LOCAL DISPLAY ADDRESS Kay Returns the Signal Generator to local keyboard control from HP IB remote control provided the instrument is not in local lockout Also displays the current HP IB address in the FREQUENCY MHZ display for as long as the key is depressed This key is also used to set the HP IB address Refer to the HP IB Address Selection in Section 2 for more information Figure 3 5 Sweep Features and LOCAL Key 2 of 2 HP 8673H Qam AM OFF Key Disables AM AM 30 Key Enables AM and selects 30 full scale modulation for 1 voit peak applied to the AM IN connector AM 100 Key Enables AM and selects 100 full scale modulation for 1 volt peak applied to the AM IN connector AM IN Connector BNC female connector with an input impedance of 6002 1 volt peak sets full scale modulation as selected by the AM 30 or 100 key AM depth varies linearly with the input signal level FM DEVIATION FM DEVIATION MHz OFF Key Disables FM FM DEVIATION Keys 03 1 3 1 3 and 10 Enables FM and selects the peak deviation sensitivity in MHz obtained when a signal is applied to the FM IN connector The peak deviation is read on the m
25. Example cont d Program Codes Comments Operation Detailed Operating Instructions Power Meter Automatic Level Control conta 4 Press the ALC PWR MTR key on the Signal Generator and set the Signal Generator range to 10 dB The UNLEVELED annunciator may come on when the power meter leveling mode is activated The calibration in the next step will eliminate this indication 5 Adjust the front panel CAL control until the UNLEVELED annunciator is extinguished Reset the VERNIER for a 0 dBm indication on the Signal Generator s front panel LVL meter and then adjust the CAL control until the power meter indicates exactly 10 dBm 6 The output level can now be set by adjusting the VERNIER for the desired output level as read on the level meter Setting the range to 0 dB will reduce the output level by 10 dB However setting the range lower than 0 dB will not change the output level until the ALC goes unleveled due to insufficient output power to overcome the additional loss in the RF path Remote 1 Perform the above steps 1 to 5 to calibrate the external ALC circuitry 2 Set the output level remotely by programming vernier settings between 10 and 3 dBm Changing the range will have the same affects as described in step 6 above Program Description Code c3 External Power Meter Leveling Mode Using external power meter leveling mode has the advantages of high stability temperature compensation and high sensitivity
26. Generator The signal level must be detected using a signal splitter or a directional coupler and a detector to provide a DC signal that is proportional to power at the remote point The Signal Generator will adjust the signal level at the RF output connector to maintain a constant level at the point where the signal is detected External ALC also enables external devices such as amplifiers mixers and other specialized devices to be inserted into the RF signal path with control of the final output level by the Signal Generator In applications where the external signal path has frequency dependent losses and or gains the RF signal at the end of the signal path will no longer be a constant amplitude over the Signal Generator s frequency range For example if a cable is used that has a constant 0 5 dB GHz loss a level error of 5 dB would occur after a 10 GHz frequency change The signal at the RF output connector of the Signal Generator has not changed but an extra 5 dB of attenuation is introduced in the signal path when the output frequency is changed System leveling mode is available on system compatible Signal Generators only To determine if a specific Signal Generator is system compatible See paragraph 3 2 System Compatibility System leveling is used with other system compatible equipment to provide the Signal Generator with the means to control the output level of the system External mixers amplifiers and other equipment may be conne
27. Generator digital sweep is composed of discrete frequencies that are produced sequentially The minimum step size is limited to the frequency resolution which is defined as the minimum change in frequency that the Signal Generator can produce The number of steps is dependent on the frequency resolution and the frequency span For information regarding sweep time see the DWELL TIME detailed operating instruction The actual change in output frequency during a sweep will not be uniform for some frequency bands and may vary up to 2 kHz This is required to accommodate sweep step sizes that are not exact multiples of the frequency resolution The sweep steps averaged over several sweep points will be equal to the selected sweep step size An example of the averaging is defining a sweep step size of 7 kHz at a start frequency of 11 GHz The minimum tuning increment at 11 GHz is 2 kHz which means that the sweep step size can be 6 kHz or 8 kHz for exact step sizes To obtain a sweep step size of 7 kHz the Signal Generator will step by 8 kHz then 6 kHz and then will repeat the sequence The average step size is 7 kHz even though the sweep does not execute exactly 7 kHz steps If the step size is reduced to 1 kHz the Signal Generator will step by 2 kHz and then 0 kHz fora 1 kHz average step size in the 2 kHz resolution frequency band Sweeps from a higher frequency to a lower frequency can be accomplished by setting the start frequency higher than the stop
28. Generator uses frequency multiplication to generate frequencies above 6 6 GHz To produce fast rise times when the frequency is multiplied a pulse injection circuit is used to pre bias the multiplication circuits The pulse injection circuit is critical for fastest rise times and minimum overshoot The Auto Peak operation measures critical parameters for the pulse injection circuit when pulse mode is enabled With pulse mode enabled a frequency change of 50 MHz or a VERNIER change 0 4 dB or more will trigger an Auto Peak operation During the Auto Peak the Signal Generator will switch to CW mode for approximately 200 microseconds while the Auto Peak operation is performed Pulse mode is then re enabled and the pulse injection circuitry uses the measured parameters to optimize the pulse risetime 3 111 Operation HP 8673H Detailed Operating Instructions Comments cont d Programming Example Error Messages 3 112 Pulse Modulation cont a The bursts of CW power due to changes in the VERNIER setting can be eliminated by using an internal scratch pad memory When an Auto Peak is performed the parameters required for the pulse injection circuitry are stored in the scratch pad memory Subsequent operation at this VERNIER setting will use the scratch pad data instead of performing another Auto Peak operation By sweeping the VERNIER over the entire ALC range 10 to 3 dBm on the 0 and 10 dB ranges the scratch pad memory wil
29. HP IB Interface idoaren e HP 82937A NOTE Any HP 9000 series 200 or series 300 controller with an HP IB interface and BASIC operating system can be used for this check Remote and Local Messages and the LOCAL Key Note This check determines if the Signal Generator properly switches from local to remote control from remote to local control and if the LOCAL key returns the instrument to local control If the Signal Generator is in remote mode that is the front panel RMT annunciator is on switch the instrument to STBY then to ON 3 25 Operation HP 8673H OPERATOR S CHECKS HP IB Functional Checks cont d Remote and Local Messages and the LOCAL Key cont d Description Serles 200 300 HP 85B BASIC Send the Remote message by setting REMOTE 719 REMOTE 719 Remote Enable REN true and addressing the Signal Generator to listen Operator s Check that the Signal Generators RMT and LSN annunciators are on Response Send the Local message to the Signal LOCAL 719 LOCAL 719 Generator Operator s Check that the Signal Generator s RMT annunciator is off but its LSN annunciator is on Response i Send the Remote message to the Signal REMOTE 719 REMOTE 719 Generator Operator s Check that both the Signal Generator s RMT and LSN annunciators are on Press the LOCAL Response key on the Signal Generator Check that the Signal Generators RMT annunciator is now off but that its LSN annunciator remains on Receiving the D
30. K Set_freq Frequency in Hz 220 Set_freq iNT Set_freq 1000 1000 Convertto MHz 230 240 IF ABS Set_freq Frequency gt 001 AND Err 0 THEN 250 DISP WARNING Requested frequency rounded to Set_freq 260 END IF 270 SUBEND End of subroutine To prevent roundoff errors from occurring the following subprogram may be used to adjust a frequency so that it is always within 1 kHz of the desired frequency 300 SUB Round_off Err Expected Expected frequency in MHz 310 Err 0 l Initialize Err 320 Band 5 330 340 IF Expected lt 18600 001 THEN Band 3 350 IF Expected lt 12300 001 THEN Band 2 360 IF Expected lt 6600 001 THEN Band 1 I 370 380 Baseband INT Expected 1000 Band 1000 Rounded fundamental 390 Round_down Baseband Band 400 IF Round_down lt gt Expected THEN Requires rounding 410 Round_up Baseband4 001 Band 420 IF ABS Round_down Expected lt ABS Round_up Expected THEN 430 Expected Round_down Minimum error is round down 440 ELSE 450 Expected Round_up Minimum error is round up 460 ENDIF 470 END IF 480 SUBEND 3 72 HP 8673H Operation Detailed Operating Instructions Frequency CW conta Programming The following program can be called to wait for a source settled indication fromthe Signal Example Generator The program will wait a maximum of 1 second before assuming the SOURCE cont d SETTLED bit is not going to be set The status byte must be cleared with the CS program code before the fre
31. The sweep frequency limits are determined by setting either the start and stop frequency or the center frequency and frequency span Setting start and stop frequency will begin the sweep at the start frequency and end at the stop frequency Setting the center frequency and sweep delta frequency will start the sweep at one half the sweep delta frequency below the center frequency and end the sweep at one half the sweep delta frequency above the center frequency Setting the CW frequency when sweep is off will also reset the sweep center frequency to the same value Setting the center frequency or sweep delta frequency will automatically recalculate the appropriate sweep start and stop frequencies and will recalculate the sweep step size Resetting the sweep start or stop frequency will reset the sweep center frequency if in sweep mode or the CW frequency if sweep is off The sweep delta frequency will be recalculated whenever the sweep start or stop frequency is changed The sweep delta frequency can be set as low as 1 kHz to as high as the maximum frequency of the Signal Generator If the sweep start frequency is set above the sweep stop frequency a negative sweep delta frequency will be stored Entering the start frequency above the stop frequency is the only way to enter a negative frequency span To set the Signal Generator to a specific sweep delta frequency 1 Press the SWEEP FREQ AF key to indicate that the next entry will be for sweep delta
32. after 1 hour warm up over temperature range 0 to 55 C except specifications for harmonically related spurious signals RF output pulse peak level accuracy and amplitude modulation which apply 15 to 35 C and after an AUTO PEAK operation has been performed Specifications for output flatness absolute level accuracy and modulation apply only when internal leveling is used Electrical Characteristics Performance Limits Conditions FREQUENCY Range Option 212 Frequency Range 2 0 12 4 GHz 1 95 12 4 GHz overrange 5 4 18 0 GHz 5 4 18 6 GHz overrange 1 kHz 2 kHz 3 kHz Option 618 Frequency Range Resolution 2 0 to 6 6 GHz gt 6 6 to 12 3 GHz gt 12 3 to 18 0 GHz Accuracy and Stability Same as reference oscillator Reference Oscillator Frequency Aging Rate 10 MHz lt 5 x 10710 day After a 10 day warmup typically 24 hours in a normal operating environment Switching Time for frequency to be within specified resolution and output power to be within 3 dB of set level CW and AM modes AUTO PEAK disabled SPECTRAL PURITY Single sideband Phase Noise 1 Hz bandwidth CW mode 2 0 6 6 GHz 58 dBc 10 Hz offset from carrier 70 dBc 100 Hz offset from carrier 78 dBe 1 kHz offset from carrier 86 dBc 10 kHz offset from carrier 110 dBc 100 kHz offset from carrier gt 6 6 12 3 GHz
33. as an external time base BLANKING MARKER BNC female connector Output impedance is 100Q nominal Provides 5V at the beginning of each frequency change for blanking a swept display to eliminate display of switching transients Goes to 5V during remainder of frequency step for Z Axis intensity marker or to OV for non marker frequencies AUX Connector Allows remote control of frequency increment display blanking register recall and start and stop sweep Refer to Table 3 3 AUX Connector Functions for additional information Figure 3 7 Rear Panel Features HP 8673H Operation OPERATOR S CHECKS 3 17 OPERATOR S CHECKS 3 18 Basic Functional Checks Description Equipment Procedure The purpose of these checks is to give reasonable assurance that the instrument is operating properly Each check has been designed to be performed with a minimum of test equipment and in as short a time as possible Therefore although these checks are extremely valuable in identifying malfunctions they are not a substitute for the Performance Tests in Section 4 which verify that the instrument is performing within its published specifications Each check is independent from the others and can be performed separately Simply press RCL 0 to preset the Signal Generator to a known state before beginning an individual check If a malfunction is suspected the entire procedure should be performed in the order given Make a no
34. be 10 since 0 dB attenuation would be required and the 10 dB range is one step above zero attenuation The following message may be displayed when programming the RF output level 24 The programmed RF output level VERNIER RANGE or both is outside the Signal Generator s range 3 65 Operation HP 8673H Detailed Operating Instructions Description Local Procedure Remote Procedure Example Dwell Time Sweep The Signal Generator performs a sweep by stepping the RF output frequency in discrete steps between the start and stop frequency of the sweep The number of steps that the Signal Generator makes between the start and stop frequency is set by the number of steps or the sweep step size The time that the Signal Generator spends on each step of the sweep is controlled by the dwell time For longer dwell times gt 50 milliseconds the sweep time is approximately equal to the number of steps multiplied by the dwell time The time required for changing frequency is not included in the dwell time Therefore for shorter dwell times the sweep will take longer than the number of steps multiplied by the dwell time To set the sweep dwell time 1 Press the DWELL key to indicate that the next entry will be for the sweep dwell time 2 Enter the desired dwell time in milliseconds using the numeric keypad If a mistake is made while entering the dwell time press the backspace key until the incorrect digit disappears Contin
35. blow fuses with the required rated current should be used Do not use repaired fuses or short circuit fuseholders To do so could cause a shock or fire hazard Before the instrument is switched on it must be set to the voltage of the power source or damage to the instrument may result The Signal Generator s RF OUTPUT is protected against reverse power applications up to 1W However for greatest protection of expensive internal components be careful not to apply any reverse power to the RF OUTPUT 3 10 Turn On Turn On Procedure The Signal Generator has a standby state and an on state Whenever the power cable is plugged in an oven is energized to keep the reference oscillator at a stable operating temperature If the Signal Generator is already plugged in set the LINE switch to ON If the power cable is not plugged in follow these instructions On the rear panel 1 Check the selection card see Figure 2 1 for correct voltage selection 2 Check that the fuse rating is appropriate for the line voltage used Fuse ratings are printed on the rear panel 3 Plug in the power cable Operation On the front panel set the LINE switch to ON NOTE The OVEN COLD status annunciator should light to indicate that the Signal Generator requires warming up The annunciator should turn off within fifteen minutes and the Signal Generator should be ready for general use Turn On Configuration The Signal Generator turns
36. checksum or other error detecting scheme allowing diagnostic and other special functions that are not normally possible with the Signal Generator Refer to Section 8 Service for additional information Messages This function enables the MESSAGE key to be read under program control After receiving an MG program code Message and when addressed to talk the Signal Generator sends a two digit number coded in ASCII followed by a Line Feed LF and EOL The codes represent entry errors and instrument malfunctions The two digit codes are explained on the operating information pull out card and in the Message Detailed Operating Instruction The Message can always be read by pressing the MESSAGE key even when the Signal Generator is in remote mode However reading the Message once either in remote or local clears it to 00 No Error whether or not the causing condition has been corrected Haa Ene ha pape HP 8673H Output Active Parameter This function allows the user to determine the present value of a specific parameter After receiving the program code for a value selectable parameter followed by the program code OA Output Active and when addressed to talk the Signal Generator will output a string over the bus consisting of the following Selected Program Code Current Numeric Value Units Terminator LF and EOI Any parameter that has a numeric value associated with it can be interrogated An exception to this output fo
37. dBm The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program will set the output level between 100 and 13 dBm If a level above 0 dBm is set and is not leveled an error will be reported 10 SUB Rf_level Err Expected Expected is in dBm 20 30 If Expected lt 100 OR Expected gt 13 THEN 40 Erra 1 50 DISP ERROR Requested output level is out of range 60 SUBEXIT 70 ENDIF 8 90 OUTPUT 719 USING 2A MG Clear old messages 100 ENTER 719 USING 2A Message 110 120 OUTPUT 719 USING 4A 4D D 2A CSLE Expected DM Set the level 130 140 OUTPUT 719 USING 4A LEOA 150 ENTER 719 USING K Level 160 170 IF ABS Level Expected gt 1 THEN 1 More than 1 dB in error 180 Err 1 190 DISP WARNING Programmed level is more than 1 dB in error 200 END IF 210 220 V SPOLL 719 Get the status byte 230 IF NOT BIT V 3 THEN GOTO 220 Walt for source te settle 240 250 IF Expected gt 0 THEN Check for unieveled 260 OUTPUT 719 USING 2A OS Get extended status byte 270 ENTER 719 USING B B V Extended 280 IF BIT Extended 6 THEN 290 Err 1 300 DISP WARNING The Signal Generator RF output is not leveled 310 END IF 320 END IF 330 340 SUBEND The following message may be displayed when setting the RF output level For a more complete description of the messages see the MESSAGES detailed operating instructions 24 The programmed RF
38. dependent on the method used to generate the system feedback signal Application Example 1 An RF signal is required to deliver a 20 to 13 dBm signal in the range of 6 to Example 12 GHz A system compatible amplifier is available that has a frequency range of 6 to 12 GHz and a maximum output level of 25 dBm The amplifier is connected to the Signal Generator and the system feedback signal from the amplifier is connected to the external ALC input connector on the Signal Generator front panel Pressing the shift key and then the SYSTEM key shifted DIODE sets the Signal Generator to system leveling mode The required output levels can be set directly using the RANGE and VERNIER controls Example 2 An amplifier and a frequency multiplier are to be connected together to form a frequency multiplier system The multiplier is system compatible and requires 17 dBm at the input The RF amplifier is capable of 20 dBm over the 6 to 12 GHz frequency range The system is connected by connecting the amplifier to the Signal Generator and the multiplier to the amplifier The system feedback signal is connected to the external ALC input connector on the Signal Generator front panel System leveling is set by pressing the shift key and then the SYSTEM key shifted DIODE The multiplied frequency can now be set using the RANGE and VERNIER controls Error The following message may be displayed when programming the RF output level Messages 24 The program
39. exceeds the Signal Generator capability To set the Signal Generator to a desired AM depth 1 Press the 30 or 100 AM range key If the desired depth is less than or equal to 30 use the 30 range for better display resolution Otherwise select the 100 range The key indicator should light when the key is pressed to indicate which range is selected 2 Connect an external oscillator to the AM input and set the frequency of the external oscillator to the desired modulation rate at an amplitude of 0 volts 3 Press the Signal Generator s AM meter mode key which is located near the front panel meter This will allow the amplitude of the external oscillator to be monitored as the desired AM depth 4 Adjust the external oscillator amplitude until the meter indicates the desired AM depth If the UNLEVELED annunciator is lighted reduce the AM depth or the Signal Generator s output level until the annunciator extinguishes The AM range can be programmed to the 100 range 30 range orAMoffusing the program codes A3 A2 or Al respectively The actual AM depth is controlled by the amplitude of the external modulation source The meter mode can be set to AM with the program code T2 An overmodulation condition can be detected by the controller by checking the status byte The ALC UNLEVELED bit of the extended status byte is used to indicate AM overmodulation The AM range and the AM depth cannot be read by the controller The AM depth is de
40. external X Y recorder and is only active during the single sweep mode A TTL logic high is used to raise the pen and a TTL logic low is used to lower the pen The pen is only lowered in single sweep and there is a 100 millisecond sweep delay for the pen to raise or lower To set the Signal Generator for a single sweep 1 Set the desired sweep parameters 2 Press the SINGLE SWEEP MODE key to arm the single sweep The key indicator will light and the RF frequency will be set to the start frequency 3 Press the SINGLE SWEEP MODE key again to begin the single sweep The sweep will continue to the stop frequency and then reset to the armed state 3 121 Operation Detailed Operating Instructions Local Procedure cont d Remote Procedure Example Program Codes 3 122 HP 8673H Single Sweep Mode conta If a new center frequency is entered when single sweep mode is active the start and s top frequencies will be reset and the single sweep will be set to the armed state in preparation for a sweep Tuning the frequency will also move the Sweep center frequency and reset the single sweep Pressing the SINGLE SWEEP MODE key during a sweep will reset the sweep to the armed state A 100 millisecond wait is executed both at the beginning of a single sweep and at the end of the sweep This wait is required for the pen of an external recorder to lower at the beginning of a sweep and raise at the end of the sweep Single sweep i
41. frequency This combination results in a negative frequency span as indicated when the frequency span is displayed Negative frequency spans can only be entered by setting the start frequency higher than the stop frequency 3 51 Operation HP 8673H Detailed Operating Instructions Comments cont d Programming Example 3 52 Auto Sweep Mode conrad An Auto Peak operation is performed whenever the RF output frequency is more than 50 MHz from the frequency at which the last Auto Peak operation was performed The Auto Peak operation optimizes the Signal Generator performance at the current frequency The Auto Peak operation produces small changes in the RF output level as the peaking is performed For applications requiring fastest sweeps Auto Peak may be disabled However with Auto Peak disabled modulation performance and maximum output power may be degraded The time required for the Auto Peak operation is not included in the dwell time setting The automatic level control ALC bandwidth is increased when sweep mode is activated This provides fast response to switching transients when sweeping In addition AM bandwidth is typically increased by 2 5 times The front panel annunciators are filtered in sweep mode to prevent false indications While sweeping the frequency changes cause a loss of phase lock and unleveled automatic level control during the frequency change To prevent constant flashing of the front panel annunciato
42. full scale modulation 6 Status Annunciators Display the internal conditions of the Signal Generator OFFSET lights when a frequency offset other than zero is entered The displayed frequency is higher OFFSET or lower OFFSET than the actual output frequency MULTIPLIER lights when a frequency multiplier greater than one is entered The displayed frequency is the output frequency times the multiplier UNLEVELED lights when RF OUTPUT is turned off more power is requested than is available no signal is applied to EXT ALC IN when PWR MTR DIODE or SYS is selected no signal is applied to PULSE IN when NORM pulse mode is selected overmoduiation occurs in AM mode or pulse width is less than 100 ns FM OVERMOD lights when the signal applied to the FM IN connector exceeds 1 Operation FREQUENCY h volt peak or when the modulation index exceeds 5 2 0 to 6 6 GHz 10 6 6 to 12 3 GHz or 15 12 3 to 18 0 GHz The modulation index is equal to the maximum peak deviation divided by fmod Refer to Table 1 1 Specifications for additional information STANDBY lights when power is applied but the LINE switch is in the STBY position OVEN COLD lights when the reference oscillator oven is not up to nominal operating temperature sUNLOCKED lights when one or mote of the internal phase lock loops is unlocked the RF OUTPUT is OFF or the INT EXT switch is in the EXT position with no external reference connecte
43. i 4 Adjust the external oscillator amplitude until the meter indicates the desired FM peak deviation If the FM OVERMOD annunciator is lighted reduce the peak deviation or increase the modulating rate until the annunciator extinguishes The peak deviation divided by the modulating rate must be less than or equal to the maximum modulation index for the carrier frequency The FM range canbe programmed to any of the six ranges or off The actual FM peak deviation is controlled by the external oscillator and is not directly programmable via the Signal Generator The meter mode can be set to FM mode with the program code T3 An overmodulation condition can be detected by the controller by checking the status byte The FM Overmodulated bit of the extended status byte is used to indicate FM overmodulation in remote mode The FM range and the FM peak deviation cannot be read by the controller The FM peak deviation is determined by the amplitude setting of the external oscillator used to provide the modulating signal and the selected FM deviation range If the output impedance of the external oscillator is 50 ohms the FM peak deviation can be determined by the controller by reading the external oscillator amplitude and multiplying by the programmed Signal Generator FM range To FM modulate the Signal Generator at 100 kHz peak deviation at a rate of 10 kHz Local 1 Press the FM 0 1 key to set the Signal Generator for 100 kHz maximum deviation Pre
44. in thick ae a 1 14 Attenuator Fixed 3 dB Attenuator Fixed 6 dB HP 8491B Option 006 Attenuator Fixed 10 dB HP 8491B Option 010 Attenuator Fixed 20 dB HP 8491B Option 020 Attenuator 10 dB Step HP 8495B Option 001 Automated adjustment programs require specific test equipment Therefore no substitute is recommended HP 8673H General Information Table 1 3 Recommended Test Equipment 2 of 3 Recommended instrument Critical Specifications Modei Usea Frequency Counter Range 10 MHz to 18 GHz HP 5343A P A Resolution 100 Hz 10 MHz Frequency Standard Output 20 1 Vrms Long Term Stability Better than 107 9 gay HP 5065A Local Oscillator Range 10 MHz to 18 GHz HP 8340B P A Level 10 MHz to 18 0 GHz 7 dBm Single Sideband Phase Noise and Spurious Signals Same as HP 8340B Logic Pulser TTL compatible HP 546A Mixer Response 1 to 18 GHz RHG DM1 18 VSWR LO lt 2 5 1 VSWR RF lt 4 0 1 Modulation Analyzer Frequency Range 150 to 990 MHz HP 8902A 11722A PA Input Level 20 to 13 dBm Amplitude Modulation Rates 25 Hz to 25 kHz Depth to 99 Accuracy 2 at 1 kHz Flatness 0 5 Demodulated Output Distortion lt 0 3 for 50 depth lt 0 6 for 90 depth Incidental Phase Modulation lt 0 05 radians for 50 depth at 1 kHz rate 50 Hz to 3 kHz bandwidth Frequency Modulation Rates
45. in discrete steps from the start frequency to the stop frequency The number of steps that the Signal Generator produces between the start and stop frequency is controlled by the number of steps or the sweep step size parameters The time that the Signal Generator remains at each step after switching frequencies is controlled by the dwell time parameter The Signal Generator has three sweep modes to accommodate a variety of applications Auto sweep mode is used when a repetitive sweep is required Auto sweep mode will step the RF output frequency from the start frequency to the stop frequency and then repeat the sweep until the sweep is turned off or a band crossing is encountered Single sweep mode will step the RF output frequency from the start frequency to the stop frequency once and then stop This mode is useful when a single sweep is taken during a measurement where the measuring device can store the results Manual sweep provides a convenient method to limit the tuning range of the frequency tuning controls In applications requiring a single band of frequencies the tuning limits can be set to cover the band of interest which allows the user to tune the frequency without having to watch the Signal Generator display to determine when the frequency is outside of the selected band There are four rear panel connectors that are used for sweep coordinating signals SWP OUT provides a signal that is 0 volts at the beginning of a sweep and 10 volts a
46. internal to the Signal Generator and frees the user from the tedious calculations required to set the actual frequency present at the local oscillator port of the harmonic mixer HP 8673H Operation Detailed Operating Instructions Multiplier Mode cont a Comments The system output frequency must be linearly related to the actual output of the Signal cont d Generator An example of a linear relationship is that the ratio of the system output frequency to the Signal Generator output frequency is a constant Care must be taken with a complicated system to maintain a linear relationship to preserve display accuracy Programming The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The Example program is used to set a frequency display multiplier Entering a 1 will disable frequency display multiplier mode 10 SUB Display_mult Err Multiplier 20 IF Multiplier gt 99 OR Multiplier lt 1 THEN 30 DISP WARNING Display multiplier is out of range 40 Err 1 50 SUBEXIT 60 ENDIF 70 Mult INT Multiplier Make sure it is an integer so 90 OUTPUT 719 USING 2A DD 2A MY Mult XF 100 110 SUBEND Error 01 Entered frequency is not within the range of the Signal Generator Messages 03 Invalid multiplier entry for system compatible instruments See paragraph 3 2 System Compatibility for more information 4 3 101 Operation HP 8673H Detailed Operating Instructions Description Local Procedure Re
47. is Messages displayed as it pertains to enabling the RF output For a more complete description of the message see the MESSAGES detailed operating instructions 90 An Auto Peak error has occurred during the Auto Peak operation This message indicates that service may be required 3 120 HP 8673H Description Local Procedure Operation Detailed Operating Instructions Single Sweep Mode The Signal Generator performs a digital sweep by stepping the RF output frequency in discrete steps from the start frequency to the stop frequency The number of steps that the Signal Generator produces between the start and stop frequency is controlled by the number of steps or the sweep step size parameters The time that the Signal Generator remains at each step after switching frequencies is controlled by the dwell time parameter The Signal Generator has three sweep modes to accommodate a variety of applications Auto sweep mode is used when a repetitive sweep is required Auto sweep mode will step the RF output frequency from the start frequency to the stop frequency and then repeat the sweep until the sweep is turned off or a band crossing is encountered Single sweep mode will step the RF output frequency from the start frequency to the stop frequency once and then stop This mode is useful when a single sweep is required for a measuring device to store results Control signals are provided at the rear panel of the Signal Generator for control o
48. is entered when automatic sweep mode is active the sweep will begin at the center of the sweep the new center frequency and continue sweeping Tuning the frequency will also move the sweep center frequency when automatic sweep mode is active If another sweep mode was enabled when auto sweep is selected the first sweep will begin at the current RF output frequency Subsequent sweeps will begin at the sweep start frequency HP 8673H Remote Procedure Example Program Codes Comments Operation Detailed Operating Instructions Auto Sweep Mode conta Automatic sweep mode is activated with the program code W1 The sweep can bereset with the program code RS Resetting the sweep will restart the automatic sweep at the start frequency The controller can monitor the END OF SWEEP bit of the extended status byte to determine when each sweep is finished The bit will be set when the stop frequency is reached and will not be reset until it is read or the status byte is cleared To sweep from 8 to 10 GHz in automatic sweep mode Local 1 Set the start frequency to 8 GHz and the stop frequency to 10 GHz 2 Press the AUTO SWEEP MODE key to activate automatic sweeping The key indicator will blink briefly at the beginning of each new sweep Remote The programming string to set automatic sweep is W2 The alpha character W can be sent as upper or lower case Program Dascription Code Ww Auto Sweep Mode The Signal
49. is lighted press the RF ON OFF key once Remote The programming string for setting the RF output level to off is RFO or RO The alpha characters can be sent as upper or lower case or even mixed upper and lower case Program Description Code RF Output Off RF Output Off RF Output On RF Output On Turning on the RF output will start an Auto Peak operation To determine when the RF output is settled the source settled bit of the status byte can be monitored Once the bit is set the RF output is settled and the application may continue 3 119 Operation HP 8673H Detailed Operating Instructions RF Output On Off conta Programming The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The Example program will enable the RF output if the parameter is set to ON or disable the output if the parameter is set to OFF 10 SUB Rf_output Err State 20 30 SELECT UPC TRIMS State Check for action 40 CASE OFF 50 OUTPUT 719 USING 3A RFO Turns RF output off 60 CASE ON 70 OUTPUT 719 USING SA CSRF1 Turns RF on and Auto Peaks 80 Wait_settle f Wait for Auto Peak to finish 90 V SPOLL 719 Get the status byte 100 IF NOT BIT V 3 THEN GOTO Wait_settle 110 CASE ELSE 120 DISP ERROR Invalid parameter amp State amp was passed 130 Er 1 140 END SELECT 160 SUBEND Error The following message may be displayed when enabling the R Fou tput The message
50. keying in the value Note that the entry is left justified at this point 3 Press the MHz units key to finish the sequence The FREQUENCY MHz display should show the entered frequency until the units key is released The FREQUENCY MHz display should now be right justified The frequency could also have been entered as 11 232334 GHz or 11232334 kHz The only difference is the placement of the decimal point and the units key pressed after the frequency has been entered using the numeric keypad Remote The programming string for setting the sweep start frequency is composed of a program code numeric data and the units terminator The frequency may be programmed in units of GHz MHz kHz or Hz To program the Signal Generator start frequency to 11232 334 MHz the possible program strings are FA11 232334GZ or FA11232 334MZ or FA11232334K2Z or FA11232334000HZ The alpha characters can be sent as upper or lower case or even mixed upper and lower case If the CW frequency changes the output frequency is valid once the SOURCE SETTLED bit of the status byte is set see Comments HP 8673H Program Codes Comments Programming Example Operation Detailed Operating Instructions Start Frequency Sweep conta Program Function Applicable Code Units FA Start Frequency Preferred Program Code Due to the use of frequency multiplication to generate frequencies above 6 6 GHz the frequency sometimes cannot be s
51. local procedure However the calibration must be performed manually The program code for diode ALC is C2 Once the calibration is complete the level can be remotely controlled by programming the VERNIER to the appropriate level Changing the range while using external diode leveling will have no affect on the level but can force the Signal Generator to lose control of the level due to insufficient attenuation lack of ALC dynamic range or too much attenuation attempted operation beyond maximum power specification The VERNIER setting can be read by the controller using the output active program code suffix To read the VERNIER setting send the program string VEOA and then read the VERNIER setting The Signal Generator will send the VERNIER setting in units of dBm If the setting is read as a string the format will be the program code VE followed by the VERNIER setting in dBm and then the units code DM To set the Signal Generator to diode leveling over the range of 10 to 0 dBm using a 20 dB directional coupler Local 1 Connect the coupler to the point where the RF power is to be leveled Connect the diode to the coupled port of the 20 dB directional coupler 2 Connect a power meter to the output of the directional coupler to monitor the actual power at the leveling point 3 Press the ALC DIODE key on the Signal Generator and set the Signal Generator range to 10 dB The UNLEVELED annunciator may come on when the diode leveling mode i
52. occur before the existing frequency When the marker frequency is generated the BLANKING MARKER and TONE MKR signals are activated to provide markers on the external display The next frequency in the sweep will be the same RF frequency except that the two rear panel marker signals are turned off This feature allows the marker to be used to mark the display while still being able to observe the response at the marker frequency without the marker signals present HP 8673H Comments cont d Programming Example Error Messages Operation Detailed Operating Instructions Marker Frequency Sweep cont d During a sweep where the marker is set to an existing sweep point the marker frequency is always generated first unless the marker frequency is set to the start frequency For a marker that is set equal to the start frequency the first generated frequency will be the existing sweep point and then the marker frequency will be generated Connecting the TONE MKR rear panel output to the Signal Generator s AM IN connector provides amplitude markers for a spectrum analyzer display The RF output is modulated at a 5 kHz rate with approximately 25 or 75 AM for the 30 and 100 ranges respectively The spectrum analyzer will display a modulated signal at each of the active marker frequencies to provide calibrated frequency markers on the display The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The p
53. on respective units g For SINGLE Mode On Master Unit press SINGLE once to enable the sweep Press it a second time to start one sweep If SINGLE is pressed during a sweep the in progress sweep stops and re enables Disabling Master Slave Mode Press SWEEP OFF on both Master and Slave Units Set instrument HP IB addresses to their previous settings All sweep indicators will be off The Master Unit TUNE Knob will now cause changes only on the Master Unit Display For more information on Master Slave Sweep see the detailed operating instructions HP 8673H 6673H SYNTHESIZED SIGNAL GEN RATOR 2 20 acnai Q RANGE dBm Display Indicates the selected range of the RF output in 10 dB steps from 90 to 10 dB Range is set by the RANGE 3 and r keys 6 Meter Monitors power level AM depth or FM deviation Meter function is selected by the MTR keys MTR Keys Select the meter function LVL selects OUTPUT LEVEL VERNIER for 10 to 3 dBm scale indication Read relative to the RANGE dB display AM selects 30 read on the 0 to 3 scale or 100 read on the 0 to 1 scale AM depth full scale A 1 volt peak signal applied to the AM IN connector develops full scale modulation FM selects FM deviation Full scale indication read on the 0 to 3 scale is 30 kHz 300 kHz or 3 MHz Full scale indication read on the O to 1 scala is 100 kHz 1 MHz or 10 MHz A 1 voit peak signal applied to the FM IN connector develops
54. on the rear panel Maximum output power is listed in Table 1 1 Option 005 The Signal Generator s RF OUTPUT connector is located on the rear panel and the attenuator is removed This combines Options 001 and 004 The specified output level is listed in Table 1 1 1 8 Mechanical Options The following options may have been ordered and received with the Signal Generator If they were not ordered with the original shipment and are now desired they can be ordered from the nearest Hewlett Packard office using the part numbers included in each of the following paragraphs nr ou CAUTION In the options below both English and metric screws are provided If your instrument s frame is stamped with the word Metric or M use metric screws otherwise use English screws The use of incompatible screws will result in damage to the frame Option 006 Chassis Slide Mount Kit This kit is extremely useful when the Signal Generator is rack mounted Access to the internal circuits and components or the rear panel is possible without removing the Signal Generator from the rack The chassis Slide Mount Kit part number is 1494 0059 An adapter is needed if the instrument rack mounting slides are to be mounted in a non HP rack The slides without the adapter can be directly mounted in the HP system enclosures The adapter part number is 1494 0061 Option 907 Front Handle Kit Ease of handling is increased with the front panel handles The
55. on to the same control settings it had before it was switched to STBY or even completely off that is if line power was removed The exception to this rule is that it always turns on in local mode Turn On Memory Check The Signal Generator performs a quick memory check at turn on It checks for a failure in ROM permanent memory or in RAM temporary memory and for the presence of correct data stored in RAM NOTE An internal battery is used to retain data in RAM during standby and off periods The data restores the last control setup and the nine storage registers If a ROM or serious RAM failure occurs the Signal Generator will attempt to turn on to its last control setup The Signal Generator might be useable but does require service If any but not all of the stored data is found to be incorrect the Signal Generator will turn on to the configuration stored in the first valid register This control setup will then be stored in registers 1 through 9 Incorrect stored data could be caused by even a single bit of data being lost due to line transients noise or other unpredictable conditions The Signal Generator should be useable and does not require service unless this situation occurs repeatedly If all of the register data has been altered for example if the battery failed the Signal Generator will re initialize to the front panel preset values stored in register 0 refer to Simplified Operation for a list of preset va
56. or OV Then connect the test cont d oscillator and oscilloscope to the Signal Generator as shown in Figure 3 8 33 Set the Signal Generator to each setting shown in the table below For each setting slowly increase the test oscillator s output level starting from OV while observing the Signal Generator s meter in AM mode The meter should indicate a smooth and continuous increase in AM depth When the meter displays the AM indicated in the table verify that the oscilloscope shows the corresponding voltage The UNLEVELED status annunciator should remain off at all times Signal Generator o o Signal Gonarator Oscilloscope FREQUENCY RANGE VERNIER AM Key Display 0 75V peak 0 75V peak 0 75V peak 0 75V peak 18 0 GHz 34 Press AM OFF Disconnect the test oscillator and oscilloscope from the Signal Generator FM Check The front panel meter is used to monitor input signal level which is proportional to FM deviation A spectrum analyzer can be used to monitor the signal at the RF OUTPUT connector for greater assurance of FM performance The FM OVERMOD status annunciator detects a FM overmodulation condition 35 Press RCL 0 to preset the Signal Generator to a known state Set Output Level RANGE to 0 dB Output Level VERNIER to 0 dBm and FM DEVIATION range to 0 03 MHz Then set the meter scale to FM 36 Set the test oscillator to 3 MHz at minimum output level or OV Then connect tes
57. or local when the Signal Generator is under program control Once the message has been read the key light turns off whether or not the causing condition has been corrected The FREQUENCY MHz and RANGE dBm displays operate in remote mode just as they do in local Hidden parameters can still be displayed in the FREQUENCY MHz display by pressing and holding their front panel keys This capability is not available to the controller since it cannot hold a program code in the same manner that an operator can hold down a key However the Output Active Parameter talk function allows the controller to read the current value of hidden parameters 3 30 Output Level Setting output level is the only front panel feature that is not operated in an identical manner in local and remote modes In local RANGE is set in steps of 10 dB and displayed in the RANGE dBm display The VERNIER knob sets the intermediate values of output power and is read on the meter In remote VERNIER is set in 0 1 dBm steps A selection of programming codes allows either combined or independent setting of the RANGE and VERNIER power The entry format is Program Code Numeric Value Units Terminator The code LE sets both range and vernier The code RA sets just the range The code VE sets just the vernier In going from local to remote the output level might change by a fraction of a dB In going from remote to local the front panel knob takes control There is no ass
58. orma compl npedz Outp IN OF ise ar inim ulse R zurati an 3 Aut ize a kHz kHz kHz er of Time rs S anel ep Ou one M Tabie Frequency Rang Op Output Level Modulation ting Characteristics to 12 4 GHz 15 to 12 4 GHz overrange to 18 0 GHz to 18 6 GHz overrange Hz 2 0 to 6 6 GHz Hz 6 6 to 12 3 GHz Hz 12 3 to 18 0 GHz to 10 dB in 10 dB steps xcept Options 001 and 005 nd 10 dB Jptions 001 and 005 only to 3 dBm continuously variable V and 100 V ranges 1 Vpk into 600 ohms nominal idth 20 Hz to 100 kHz f 100 kHz V 300 kHz V 1 MHz V V and 10 MHz V 1 Vpk into 50 ohms nominal aviation the smaller of 10 MHz or to 6 6 GHz 6 to 12 3 GHz 2 3 to 18 0 GHz idth 100 Hz to 3 MHz for 30 kHz V anges 3 kHz to 3 MHz for 300 kHz V z V and 10 MHz V ranges 3V on lt 0 5V off xde lt 0 5V on gt 3V off hms nominal gt 80 dB mes lt 35 ns zd Pulse Width lt 100 ns Frequency de to 1 MHz 3top Frequencies or Center Frequency AF ingle and Manual sweep span to as small as to 6 6 GHz to 12 3 GHz 3 to 18 0 GHz io 9999 5 ms per step ep Connections Reference Z Axis Blanking Markers put Penlift Operator s Checks cont d functions Two procedures are provided as described below Basic Functional Checks This procedure found in paragraph 3 1 requires a function generator a microwave frequency counter a
59. other methods The detector however must be operating in the square law region for calibrated output level control To set the Signal Generator for external diode leveling 1 Connect the diode to the remote point using a directional coupler For calibrated output levels the diode must be operating in the square law region If the diode is above the square law region typically gt 20 dBm a change in the VERNIER setting of 1 dB will produce less than 1 dB change in actual RF output level If the diode is in the linear region a 1 dB change in the VERNIER setting will produce a 0 5 dB change in the leveled power The ALC circuitry will still produce leveled power output for any diode operating region but meter calibration and HP IB control will be uncalibrated 2 Set the Signal Generator range to at least 10 dB above the range required for the desired RF output level The range may have to be adjusted to compensate for losses and gains in the RF signal path If the RF signal path will have a relatively high loss a higher Signal Generator range will be required 3 Connect the diode output to the external ALC input of the Signal Generator The detector output typically varies from 0 05 to 5 millivolts for the square law region 4 Press the ALC DIODE key to set the Signal Generator to external diode ALC mode 5 Connect a power meter to the output of the directional coupler the output port not the coupled port The power meter will be
60. power meter power sensor a crystal detector and interconnecting cables It assures that m front panel controlled functions are being properly executed by the Sigi Generator iz HP IB Functional Checks These procedures found in paragra 3 19 require an HP IB compatible computing controller an HP IB interface an connecting cable The procedures check all of the applicable bus message summarized in Table 3 3 The HP IB Checks assume that front panel operati has been verified by performing the Basic Functional Checks 3 7 Operator s Maintenance WARNING For continued protection against fire hazard replace the line fuses with 250V fuses of the same rating only Do not use repaired fuses or short circuited fuseholders Operator s maintenance consists of replacing defective fuses and adjusting L mechanical zero of the front panel meter The primary power fuse is located within the Line Power Module Assemb Refer to Figure 2 1 for instructions on how to change the fuse To mechanically zero the front panel meter set the LINE switch to the STE position and place the Signal Generator in its normal operating position Turn tuc mechanical zeroing adjustment clockwise to move the Operator s Maintenance cont d needle up scale or counterclockwise to move the needle down scale T zero point is located at the left end of the 0 1 or the 0 3 scales DO NOT ze gt on the left end of the top dB scale at 10 because this is no
61. protection has been impaired the instrument must be made inoperative and be secured against any unintended operation If this instrument is to be energized via an auto transformer for voltage reduc tion make sure the common terminal is connected to neutral that is the grounded side of the mains supply Servicing instruction are for use by service trained personnel only To avoid dangerous electric shock do not perform any servicing unless qualified to do so Adjustments described in the manual are performed with power supplied to the instrument while protective covers are removed Energy available at many points may if contacted result in personal injury Capacitors inside the instrument may still be charged even if the instrument has been disconnected from its source of supply For continued protection against fire hazard replace the line fuse s only with 250V fuse s of the same current rating and type for example normal blow time delay etc Do not use repaired fuses or short circuited fuseholders SAFETY SYMBOLS Instruction manual symbol the product will be marked with this symbol when it is necessary for the user to refer to the instruc tion manual see Table of Contents for page references s Indicates hazardous voltages a Indicates earth ground terminal The WARNING sign denotes a hazard It calls attention to a procedure practice or the like which ifnot correctly performed or adh
62. range and the peak is performed after a brief settling time Auto Peak will slow the effective sweep time for low dwell settings The Auto Peak operation will occur every 50 MHz during sweep modes With FM selected the effective sweep time will be increased further Auto Peak may be disabled during sweep modes at the expense of maximum available power and modulation performance Pulse modulation requires a longer auto peak operation to maintain pulse performance Therefore puise modulation while sweeping will dramatically lengthen sweep time The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program will execute an Auto Peak operation and then return after the Auto Peak operation is complete 10 SUB Peak Err 20 OUTPUT 719 USING 4A CSK1 Force an Auto Peak and enable peaking 30 40 V SPOLL 719 50 IF NOT BIT V 3 THEN GOTO 40 Wait for completed Auto Peak 60 70 OUTPUT 719 USING 2A MG Check for error 80 ENTER 719 USING 2A Message 90 IF Message 90 THEN 100 Err 90 110 ELSE 120 Err 0 130 SUBEND If an Auto Peak operation cannot be performed due to low power output or a mistuned filter error message 90 will be issued to indicate that service is required 3 49 p Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 50 Auto Sweep Mode The Signal Generator performs a digital sweep by stepping the RF output frequency
63. settings and the RF output level the sum of the VERNIER and RANGE settings can be read by the controller using the output active program code suffix To read the VERNIER setting 12 0 to 3 dBm send the program string VEOA and then read the VERNIER setting The Signal Generator will send the setting in units of dBm If the setting is read as a string the format will be the program code VE followed by the setting in dBm and then the units code DM The RANGE setting is read by sending the program string RAOA and then reading the RANGE setting The Signal Generator will send the range in units of dB 90 to 20 dB If the RANGE setting is read as a string the format will be the program code RA followed by the RANGE setting in dB and then the units code DM The RF output level is read by sending the program string LEOA and then reading the output level The Signal Generator will send the range in units of dBm 102 to 23 dBm If the RF level is read as a string the format will be the program code LE followed by the system RF level and then the units code DM The program code AP or PL can be used instead of LE but the program code sent by the Signal Generator will always be LE To set the Signal Generator to system leveling using an external system compatible amplifier Local 1 Connect the amplifier to the output of the Signal Generator 2 Connect the system feedback signal from the amplifier to the external ALC input connector on the
64. the start and stop frequency is set by the number of steps or the sweep step size Setting the number of steps in a sweep will change the sweep step size and setting the sweep step size will change the number of steps Sweep step size is calculated by dividing the frequency span AF by the number of steps when the number of steps is set The number of steps is set by dividing the frequency span AF by the sweep step size when the sweep step size is entered The Signal Generator is capable of 1 to 9999 steps within a sweep span as long as the calculated step size is greater than 1 kHz For a sweep with one step the Signal Generator will produce the start frequency and the stop frequency Sweep step size can be set between 1 kHz and the currently defined sweep span as long as the calculated number of steps is between 1 and 9999 steps Entering a sweep step size larger than the sweep span will set the step size equal to the span and will cause the Signal Generator to issue a message To set the sweep step size 1 Press the STEP key to indicate that the next entry will be for the sweep step size or the number of steps The only difference in entering the two is the units terminator 2 Enter the desired sweep step size using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue entering the correct digits until the sweep step size in the FREQUENCY MHz displ
65. the sweep marker frequency within the sweep A sweep marker is deactivated by pressing the MKR key entering the marker number using the numeric keypad and then pressing the MKR OFF units key All five markers can be deactivated by pressing the MKR key and then pressing the MKR OFF units key HP 8673H Local Procedure cont d Remote Procedure Example Operation Detailed Operating Instructions Marker Frequency Sweep contd The sweep marker frequency for a given marker can be displayed by pressing the MKR key and then entering the marker number using the numeric keypad The sweep marker frequency for that marker will be displayed as long as the marker number key is pressed This sequence is also used to activate a marker so reading a sweep marker frequency will activate the marker The active markers can be displayed by pressing and holding the MKR key The active markers will be displayed in the FREQUENCY MHz display in the order in which they will occur For example if marker 3 is set to 11 GHz and marker 5 is set to 10 GHz the marker display will display 5 and then 3 as long as both sweep marker frequencies are within the current sweep Each of the five markers can be programmed to any frequency within the Signal Generator s frequency range Above 6 6 GHz the programmed frequency may be rounded by the Signal Generator to be compatible with the 2 or 3 kHz frequency resolution at the programmed frequency Specifying a m
66. through 90 are service related errors This type of error message should be referred to service trained personnel See Section 8 in the Service Manual for more information To read the error code 1 Press and hold the front panel MESSAGE key to read the two digit error code 2 Refer to Table 3 8 Error Messages for an explanation of the error codes Error messages can be read using the HP IB To do so send the program code MG to the Signal Generator then read back the two digit error code 00 to 99 Refer to Table 3 8 Error Messages for an explanation of the message codes Error messages are not cleared in remote mode by sending new program strings To ensure correct error messages clear MESSAGE by reading the error code via front panel or HP IB before programming the Signal Generator with a new program string This will clear any previous messages that have not been read so the message indicated after sending the programming string will be the response to that programming string Program Description Code Enable Message output 3 97 Operation Detailed Operating Instructions HP 8673H Messages cont d The Entry Error bit of the status byte is analogous to the MESSAGE key When the service request mask is used to generate an SRQ on an entry error the MESSAGE must be read via the front panel or HP IB before the SRQ is cleared Clearing the status byte will not clear Comments SRQ until the message has bee
67. to tum on the carrier If the TTL high level is to tum off the carrier select pulse complement mode by pressing the PULSE COMPL key Pulse modulation can be programmed to the normal or complement mode using the program codes P2 or P3 respectively The program codes PO and P1 tum off pulse modulation The pulse mode NORM or COMPL cannot be read by the controller The pulse width and pulse repetition rate are set by the external pulse source The controller can interrogate the external source to determine pulse width and repetition rate To pulse modulate the Signal Generator at 1 MHz with a 100 nanosecond pulse width Local 1 Set the external pulse source for a TTL compatible pulse of 100 nanosecond width at a pulse repetition frequency of 1 MHz 2 Connect the external pulse source to the PULSE IN connector 3 Press the pulse NORM key to activate pulse modulation Remote The programming string for setting pulse normal mode on the Signal Generator is P2 The modulating signal is set by programming the external modulating signal source The alpha character P can be sent as upper or lower case HP 8673H Program Codes Comments Operation Detailed Operating Instructions Pulse Modulation conta Description Pulse Off Pulse Off Pulse Normal Mode Pulse Complement Mode Program Code PO Overmodulation in pulse mode due to peak level accuracy degradation narrow pulse widths or an extremely low duty
68. used to calibrate the output level to the Signal Generator level meter HP 8673H Local Procedure cont d Remote Procedure Example Operation Detailed Operating Instructions Diode Automatic Level Control conta 6 Adjust the ALC CAL control on the Signal Generator front panel until the U NLE VELED annunciator is extinguished Set the Signal Generator VERNIER for a 0 dBm indication on the Signal Generator s level meter Continue adjusting the CAL control until the power meter indicates the desired level For example for a desired level in the range of 17 to 10 dBm using a 20 dB directional coupler adjust the CAL control for a power meter reading of 10 dBm Once the calibration is complete the level at the output of the directional coupler can be varied over a 3 to 10 dB range If tuming the CAL control fully clockwise does not have sufficient range to calibrate the output level set the range higher until the calibration can be completed If the output level cannot be set low enough step the RANGE down until the calibration can be performed as per this step Using the highest range will provide the best compensation for increasing losses higher power levels at the Signal Generator output Using a lower range will provide the best compensation for decreasing losses See the comments section for more information on selecting the optimum range The equipment setup for remote control of diode leveling is the same as the
69. will continue to be set until the key is released The FRONT PANEL KEY PRESSED bit will only be set once for this condition CHANGE IN EXTENDED STATUS The status byte can be read using a serial poll but the extended status byte requires a program code to be sent to the Signal Generator and then the controller must read both the status byte and the extended status byte from the Signal Generator The CHANGE IN EXTENDED STATUS bit is used to indicate that the extended status byte has changed from its value the last time was read This enables the status byte to be monitored using a serial poll until there is a status change in the extended status byte Once a change has occurred the controller can read the extended status byte to check the instrument status For more information regarding the use of this status bit see the Comments section SOURCE SETTLED The Signal Generator requires a certain length of time to process a command For example when setting frequency the Signal Generator can require anywhere from several milliseconds to 50 milliseconds to change frequency and settle the RF output level The actual time required depends on the frequency change see CW Frequency If the application waits 50 milliseconds the specified worst case frequency switching time after each frequency change the RF output will be settled Note that the wait must start after the Signal Generator has received the frequency programming string For controllers wit
70. 00 MHz STOP to 10 000 000 MHz AF to 2000 000 MHz SWEEP to OFF STEP to 100 Steps 20 000 MHz DWELL to 20 ms TUNE Knob to ON All Status Annunciators off MESSAGE key light off Frequency Check The FREQUENCY MHz display and SUNLOCKED status annunciator are used to check that the internal phase lock loops remain phase locked across their tuning range The actual frequency at the RF OUTPUT connector is not checked However this connector can be monitored with a microwave frequency counter or spectrum analyzer for greater assurance that the Signal Generator is operating properly 8 Press RCL 0 9 Set the Signal Generator frequency to 2 000000 GHz Option 212 or 6 000000 GHz Option 618 and FREQ INCREMENT to 1 111111 GHz HP 8673H Operation OPERATOR S CHECKS Basic Functional Checks cont d Procedure 10 cont d 11 Step the Signal Generator from 2 000000 GHz to 12 000000 GHz Option 212 or 6 000000 GHz to 16 000000 GHz Option 618 in 1 111111 GHz steps Verify that the UNLOCKED annunciator remains off at each step NOTE Fast stepping or tuning of frequency may cause the pUNLOCKED annunciator to flash on momentarily This is normal and does not indicate a malfunction Also note that some steps will not exactly equal 1 111111 GHz depending upon the resolution of each frequency band Set FREQUENCY to 2 GHz Option 212 or 5 4 GHz Option 618 and then to 12 4 GHz Option 212 or 18 0 Option 618 Veri
71. 05A B HP 5006A A the models listed are approved for usage Spectrum Analyzer Frequency Range 20 Hz to 300 kHz HP 3585B A P Resolution Bandwidth 3 Hz minimum Frequency Span Division 20 Hz minimum Noise Sidebands gt 90 dB below CW signal 3 kHz offset 100 Hz IF bandwidth Input Level Range 0 to 70 dBm Log Reference 70 dB dynamic range in 10 dB steps Accuracy 0 2 dB Tracking Generator 0 dBm to 11 dBm Power Amp Frequency 100 kHz to 1 3 GHz Gain 22 5 dB Output Power gt 6 dBm HP 8447E Note HP 8447F is a dual Spectrum Analyzer System Frequency Range 10 MHz to 18 GHz HP 8566B PLA Frequency Span Division 1 kHz minimum Amplitude Range 0 to 70 dB Noise Sideband gt 75 dB down 30 kHz from signal at 1 kHz resolution bandwidth Required for servicing and troubleshooting HP 11726A Center Frequency 150 to 200 MHz HP 8340B or Center Frequency Resolution 0 1 MHz HP 86222B 8620C Sweep Range 10 and 200 MHz Test Oscillator Level 0 to 3V into 502 or 300Q HP 8116A C P Range 10 kHz to 10 MHz 1 Support Kit Sweep Oscillator C Operator s Check P Performance Tests A Adjustments T Troubleshooting The HP 8903B is recommended for the combined use as an analyzer and audio source A separate audio analyzer and an audio source can be used if critical specifications are met 2 RHG Electronics Laboratory
72. 12 3 GHz gt 12 3 to 18 0 GHz All ranges peak deviation is linearly controlied by varying input level between 0 and 1 Vpk 100 kHz rate 100 kHz rate lt 100 kHz peak deviations lt 1 MHz 1 9 General Information HP 8673H Table 1 1 Specifications 5 of 6 Electrical Characteristics Performance Limits DIGITAL SWEEP cont d Maximum equals the maximum Step Size sweepspan minimum is equal to the greater of the frequency resolution or span divided by 9999 Conditions g Maximum of 9999 frequency points per sweep Dwell Time Set from 1 to 255 ms per step Maximum Sweep Width Option 212 Option 618 Manual Single and Auto sweep modes 2 0 to 12 4 GHz 5 4 to 18 0 GHz Markers 5 independent fixed frequency markers set from front panel Resolution and accuracy are identical to RF output frequency specifications REAR PANEL AUXILIARY CONTROL CONNECTOR 14 Pin Connector Inputs Stop Sweep HP 8410B C Compatible Trigger Output Service Function Frequency Increment Frequency Decrement Blank Frequency Display Recall Register 1 Sequential Register Recall Outputs Trigger HP 8410B C Compatible End Sweep Negative Z axis Blanking Ground input Required Contact closure to ground or 5 ps negative true TTL pulse Internal debounce circuit available to debounce extemal inputs Outputs 5
73. 12 GHz Entering 12 GHz will produce an actual frequency of 6 GHz To enter a frequency display multiplier 1 Press the blue shift key to access the shifted key functions 2 Press the MULT shifted STRT key to indicate that the next entry will be for display multiplier 3 Enter the desired display multiplier using the numeric keypad The FREQUENCY MHz display should display the entry 4 Press the X FREQ units key to finish the entry The display multiplier will be displayed until the X FREQ key is released Once the key is released the FREQUENCY MHz display will indicate the multiplier value times the previous display For example if the Signal Generator RF output frequency was 9 GHz before the multiplier was entered and the multiplier is three the display will indicate 27 GHz The multiplier annunciator will be lighted to indicate that the displayed frequency is an integer multiple of the actual output frequency Entering a multiplier of 1 will disable the frequency multiplier mode Valid entries are 1 to 99 For some sweep displays the least significant digits may be truncated due to insufficient space to display large frequencies corresponding to large frequency display multipliers Entering a frequency with a display multiplier active will display the entered frequency The actual frequency at the RF output will be the displayed frequency divided by the multiplier The program code for display multiplier is MY The programm
74. 240 Dev D2 Code for 30 kHz deviation 250 V_required Deviation 03 In peak volts into 50 ohms 260 ENDIF 270 IF Deviation 0 THEN 280 Dev D1 Turns FM off 280 V_required 0 300 END IF 310 320 OUTPUT 719 USING 2A Dev Program range 330 SUBEND Error There are no messages associated with the setting of frequency modulation Messages HP 8673H Description Local Procedure Remote Procedure Operation Detailed Operating Instructions Internal Automatic Level Control Automatic Leveling Control ALC is used to maintain a constant power level at a given point Internal ALC provides a leveled output signal at the RF output connector that is held constant over the entire frequency range of the instrument Internal ALC is the simplest mode to operate and requires no additional equipment to use The RF output level is controlled over the entire frequency range of the instrument with a dynamic range of 100 dBm up to a maximum of 13 dBm The actual maximum leveled power is dependent on RF output frequency and is specified within frequency bands To level the RF output over the entire frequency range of the Signal Generator the output level must be set no higher than the maximum leveled power of the lowest power frequency typically the highest frequency To set the Signal Generator for internal leveling 1 Press the Signal Generator ALC INT key to set the ALC circuitry to detect the RF output power internally 2 Set t
75. 3 Note that the roundoff error is only 1 kHz if 12 399999 GHz is programmed instead of 12 4 GHz Frequencies above 6 6 GHz are produced by multiplying the baseband frequency 2 0 6 6 GHz The time it takes to switch from one frequency to another depends on the largest baseband lt 6 6 GHz frequency digit being changed Generally the smaller the digit being changed the shorter the switching time For example a change of 3 kHz the 1 kHz digit would be faster than a change of 3 GHz the 1 GHz digit Typical switching times by largest digit being changed for frequencies less than 6 6 GHz can be summarized as follows HP 8673H Comments cont d Operation Detailed Operating Instructions Frequency CW conta Largest Digit Time to be Changed Within 1 kHz 100 MHz 10 MHz 1 MHz 100 kHz 10 kHz 1 kHz For frequency changes involving frequencies above 6 6 GHz the actual frequency digits being changed must be determined by dividing the frequency change by two 6 6 to 12 3 GHz or three 12 3 to 18 0 GHz The result will indicate which digits of the fundamental unmultiplied frequency will actually change The frequency switching time will depend only on which digits of the baseband frequency are changing For applications that require fastest execution the SOURCE SETTLED bit of the status byte can be used Once the bit is set the output is valid and the program may continue If the frequency is programmed and the statu
76. 310 IF BIT Stat2 0 THEN PRINT HP 8673 Self Test Failed 320 IF BIT Stat2 1 THEN PRINT HP 8673 FM is overmodulated 330 IF BIT Stat2 3 THEN PRINT HP 8673 is using External Ref 340 IF BIT Stat2 4 THEN PRINT HP 8673 is not phase locked 350 IF BIT Stat2 5 THEN PRINT HP 8673 has had a power failure 360 IF BIT Stat2 6 THEN PRINT HP 8673 is not leveled 370 ENDIF 380 SUBEND Error All messages except NO ERROR will set the ENTRY ERROR bit of the status byte Errors 95 Messages through 99 are related to the self test performed at power up If one of these errors is reported and the instrument is still functional the SELF TEST FAILED bit in the extended status byte will be set 3 136 HP 8673H Description Local Procedure Remote Procedure Operation Detailed Operating Instructions Steps Sweep The Signal Generator performs a sweep by stepping the RF output frequency in discrete steps between the start and stop frequency of the sweep The number of steps that the Signal Generator makes between the start and stop frequency is set by the number of steps or the sweep step size Setting the number of steps in a sweep will change the sweep step size and setting the sweep step size will change the number of steps Sweep step size is calculated by dividing the frequency span VF by the number of steps when the number of steps is set The number of steps is set by dividing the frequency span VF by the sweep step size
77. 4 GHz For applications that require fastest execution the SOURCE SETTLED bit of the status byte can be used Once the bit is set after a frequency has been programmed the output is valid and the program may continue If the frequency is programmed and the status byte is not checked the program should wait at least the frequency switching speed time before assuming the output valid If the status byte is to be used to monitor settling the program string that sets the frequency should start with the program code CS This will clear any previous setting of the SOURCE SETTLED bit to avoid an incorrect indication The following programs are written in BASIC for HP 9000 Series 200 or 300 controllers The following program is used to set the Signal Generator to the sweep start frequency specified by the variable called Expected The desired value must be in MHz and should be within the frequency range of the Signal Generator 10 SUB Sweep_start_set Err Expected Expected frequency in MHz 20 OUTPUT 719 USING 2A MG Read message from 8673 30 ENTER 719 USING 2A Message To clear any old messages 40 Frequency INT Expected 1000 1000 Round off to nearest kHz 50 OUTPUT 719 USING 4A 5D DDD 2A CSFB Frequency MZ Update status 60 CALL Settled Wait for source to settle 70 OUTPUT 719 USING 2A MG Check for message from 8673 3 145 Operation HP 8673H Detailed Operating Instructions Stop Frequency Sweep conta Progr
78. 47 dBm Remote The programming string for the setting the RF output level is composed of a program code numeric data and the units terminator The RF output level may be programmed directly or the RANGE and VERNIER may be programmed separately To program the Signal Generator to a level of 56 dBm the possible program strings are s LE 56DM or RA 50DBVE 6DM In addition the program code could be AP or PL instead of LE The alpha characters can be sent as upper or lower case or even mixed upper and lower case The Signal Generator RF output level is valid once the SOURCE SETTLED bit of the status byte is set see Comments The units terminator could be DB or DM The Signal Generator accepts either terminator for all power related settings HP 8673H Program Codes Comments Programming Example Operation Detailed Operating Instructions Vernier Output Level conta Program Function Applicable Code oe Units Vernier Setting LE RF Output Level AP RF Output Level PL RF Output Level Preferred Program Code The VERNIER controls the automatic level control ALC circuit dir ctly The ALC is capable of controlling the RF output level over a 10 to 13 dBm range Additional dynamic range is provided by a 90 dB step attenuator that is controlled by the RANGE setting In remote mode a Digital to Analog Convetter DAC is substituted for the front panel VERNIER control The resolution of th
79. 491A Option 003 AC Voltmeter Range 1 mV to 10V Accuracy 1 5 of full scale 41 5 of reading Frequency Response 3 kHz to 3 MHz Range de to 1 GHz Accuracy 0 5 dB SWR lt 1 3 Range de to 18 GHz Accuracy 0 6 dB SWR lt 1 6 Range dc to 12 4 GHz Accuracy 0 6 dB SWR lt 1 3 Range dc to 18 GHz Accuracy 1 0 dB SWR lt 1 6 Range de to 18 GHz Accuracy 7 SWR lt 2 2 Audio Analyzer Frequency Range 20 Hz to 100 kHz HP 8903B Accuracy 4 of full scale Audio Source Frequency Range 20 Hz to 100 kHz HP 8903B Output Level 1 mV to 6 V open circuit Flatness 2 5 Cable Special Special see Figure 1 2 Locally Fabricated Interconnect Controller HP IB HP IB compatibility as defined by IEEE Standard HP 85A 82937A 488 1978 and the identical ANSI Standard MC1 1 00085 15001 SH1 AH T2 TEO L2 LEO SRO RLO PPO DCO 00085 15002 DTO and Cl 2 3 4 5 00085 15003 00085 15004 00085 15005 or HP 85B 82937A 00085 15002 00085 15004 00085 15005 Crystal Detector Frequency Range 2 to 18 GHz HP 08673 60083 Frequency Response 1 5 dB Curent Probe Probe _ Curent Probe Frequency Range 2t035 MHz SSCS Range 2 to Frequency Range 2 t035 MHz lt lt MHz HP 1110B za Digital Voltmeter Automated adjustment programs require specific test HP 3456A or HP 3455A P A T equipment No substitute is recommended Foam Pads 2 required 43 x 58 cm 17 x 23 in 5 cm 2
80. 5060 9462 Figure 2 4 Hewlett Packard Interface Bus Connection MIDIAMAaANUL HP 8673H NC STOP SWEEP NC SERVICE NO DISPLAY TRIGGER SINGLE SWEEP GROUND FREQ INCREMENT DOWN END OF SWEEP FREQ INCREMENT UP TRIGGER OUTPUT RECALL NEXT NEGATIVE BLANKING RECALL 1 14 Pin Micro Ribbon 57 Series Connector Logic Levels The rear panel AUX connector logic levels are TTL compatible 5 microseconds negative true TTL pulse or a contact closure to ground Internal Jumper Selection If the signals to the rear panel AUX connector require contact debouncing e g for mechanical switches an internal jumper must be changed The jumper is installed at the factory for electronically clean input signals i e those signals that do not require the use of the debounce circuit The jumper is located on the A2A2 Key Code board To change the jumper position the top cover of the Signal Generator must be removed WARNINGS This task should be performed by service trained persons who are aware of the potential shock hazard of working on an instrument with Protective covers removed To avoid hazardous electrical shock the line mains power cable should be disconnected before removing the Signal Generator s cover The following procedure describes how to locate and change the jumper position a Set the LINE switch to STBY and disconnect the line power cable b Remove the Signal Generator s top cover by removing the two plastic feet from th
81. 6 and 12 3 GHz or by three if it is between 12 3 and 18 0 GHz If the result is a whole number no remainder the frequency can be set to the desired value For example 12 4 GHz divided by three it is between 12 3 and 18 0 GHz is 4133333 33 kHz Since the dividend is not a whole number this frequency cannot be set exactly The nearest frequencies that can be set are 12 399999 GHz 4 133333X3 and 12 400002 GHz 4 133334X3 Note that the roundoff error is only 1 kHz if 12 399999 GHz is programmed instead of 12 4 GHz Reading the sweep center frequency will not indicate frequency rounding The programmed frequency is saved for use in calculating the appropriate sweep start and stop frequencies To avoid errors during this calculation due to roundoff the sweep center frequency is saved and the calculated start and stop frequencies are rounded off The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The following program is used to set the Signal Generator sweep center frequency to the frequency specified by the variable Expected The desired value must be in MHz and should be within the frequency range of the Signal Generator 10 SUB Center_freq_set Err Expected Expected frequency in MHz 20 OUTPUT 719 USING 2A MG Read message from 8673 30 ENTER 719 USING 2A Message to clear any old messages 40 Frequency iNT Expected 1000 1000 Round off to nearest kHz 50 OUTPUT 719 USING 4A 5D DDD 2A CF Fr
82. 60 Output Level Switching Waveform 4 63 Level Switching Time Measurement Waveform 4 64 Pulse ON OFF Ratio Test Setup oo ceeeeeee eee 4 65 Pulse Rise Fall Time and Overshoot Test Setup 4 67 Pulse Rise Fail Time and Overshoot Waveform 4 69 Pulse Definitions is c ss sicsecsessesusesosvesesetnetecs 4 70 Pulse Peak Level Accuracy Test Setup a 4 73 4 40 Pulse Peak Level Accuracy Measurement a 474 AM Bandwidth Test Setup eee 476 AM Accuracy Test Setup weve 4 78 Incidental FM Test Setup reve 4 80 FM Frequency Response Test Setup 4 82 External FM Accuracy and Meter Accuracy Test Setup 4 84 Incidental AM Test Setup 4 87 Page Talk Functions ea 3 39 Response to a Clear Message 3 39 3 42 3 44 3 98 HP IB Program Codes Index of Detailed Operating Instructions Error Messages Abbreviated Performance Test Record 4 20 High Level Accuracy Test Record a 4 57 Low Level Accuracy Test Record vere 4 59 Performance Test Record seve 4 89 v vi HP 8673H Warranty m CERTIFICATION Hewlett Packard Company certifies that this product met its published specifications at the time of shipment from the factory Hewlett Packard further certifies that its calibration measurements are traceable to the United States National Bureau of Standards to the extent allowed by the Bureau s calibration facility and to the calibration facilities of other
83. 78 220 240V OPERATION PLUG NEMA 6 15P CABLE HP 8120 0698 220 240V OPERATION 220 240V OPERATION PLUG CEE7 Vil CABLE HP 8120 1689 PLUG CEE22 V1 CABLE HP 8120 1860 PLUG BS 1363A CABLE HP 8120 1351 The number shown for the plug is the industry identifier for the plug only The number shown for the cable is an HP part number for a complete cable including the plug Figure 2 2 Power Cable and Mains Plug Part Numbers 2 2 Fir 50 5n HP iB Address Selection cont d NOTE The HP IB address switches can be set without removing any circuit boards from the Signal Generator If any circuit boards are removed observe all electrostatic discharge precautions to avoid damaging the Signal Generator a Set the LINE switch to STBY Disconnect the line power cable b Remove the Signal Generator s top cover by removing the two plastic standoffs from the rear of the top cover and loosening the screw at the middle of the rear edge of the top cover Table 2 1 Allowable HP IB Address Codes Address Switches Pr aen Decimal 7 Char Char Equiv MSB i LSB acter acter alent olo ooo SP E ao o o0 o0 1 A I T o o lo 8 j 2 ol oloi T F 3 0 i BEDRAE D 5 4 0 o0f i1f 0 1 E 5 9 0 1 1 0 F a 6 olol n e m o i o o
84. 8 Conducted and radiated interference is within the requirements of methods CE03 and REO2 of MIL STD 461A VDE 0871 and CISPR publication 11 29 kg 64 lb 146 mm 5 7 in 425 mm 16 8 in 620 mm 24 4 in For ordering cabinet accessories module sizes are 51 4H IMW 23D 1 11 General Information HP 8673H Table 1 2 Supplemental Characteristics 1 of 2 Supplemental characteristics are intended to provide information useful in applying the instrument by giving typical but non warranted performance parameters FREQUENCY Internal Reference The internal reference oscillator accuracy is a function of time base calibration aging rate temperature effects and line voltage effects Typical temperature and line voltage effects are lt 1 x 107 10 and lt 5 x 10710 45 to 10 line voltage change Reference oscillator is kept at operating temperature in STANDBY mode with the instrument connected to mains power For instruments disconnected from mains power less than 24 hours the aging rate is lt 5 x 10 10 day after a 24 hour warmup External Reference Input 5 or 10 MHz at a level of 0 1 to 1 Vrms into 50 ohms Stability and spectral purity of the microwave output will be partially determined by characteristics of the external reference frequency Reference Outputs 10 MHz and 100 MHz at a level of 0 2 Vrms nominal into 50 ohms SPECTRAL PURITY Single sideband Phase Noise 1 Hz BW CW mode 2 0
85. 902A 11722A Input Level 20 to 13 dBm 1 17 Frequency Counter Generat Information HP 8673H Table 1 4 Abbreviated Performance Test Recommended Test Equipment 2 of 2 Recommended _ Critical Specifications Modei Measuring Receiver Amplitude Modulation cont d Rates 25 Hz to 25 kHz Depth to 99 Accuracy 2 at 1 kHz Flatness 0 5 Demodulated Output Distortion lt 0 3 for 50 depth lt 0 6 for 90 depth Incidental Phase Modulation lt 0 05 radians for 50 depth at 1 KHz rate 50 Hz to 3 kHz bandwidth Frequency Modulation Rates 25 Hz to 25 kHz Deviation to 99 kHz Accuracy 2 at 1 kHz Bandwidth 100 MHz Vertical Sensitivity 10 mV div Vertical Input ac de or 50Q de coupled External Trigger Capability Delayed Sweep Capability One Shot Digitizer Frequency Range 50 MHz to 18 GHz Input Impedance 50Q SWR lt 1 25 Max Input Level 15 dBm Oscilloscope HP 1980B 19860A Power Meter and Sensor HP 436A HP 8481A 20 dB Preamp Preamp Frequency 100 kHz to 400 kHz Gain 26 6 dB Output Power gt 7 dBm Noise Figure lt 8 5 dB Impedance 50Q HP 8447D 20 dB Power Amp Power Amp Frequency 100 kHz to 400 kHz Gain 22 5 dB Output Power gt 6 dBm Noise Figure lt 5 dBm Impedance 509 Rate 10 Hz to 4 MHz Rise and Fall Times lt 5 ns Out
86. AL Control Adjusts the power level at the load when using a diode detector or power meter for external leveling from 2 to 12 4 GHz Option 212 or 5 4 to 18 0 GHz Option 618 AUTO PEAK Key Maximizes power at the output frequency and optimizes pulse shape for pulse modulation D EXT ALC IN Connector BNC female connector that accepts positive or negative leveling signals from a diode detector power meter or system reference Figure 3 3 Output Level Features HP 8673H FREQUENCY Key Used as a prefix to the Data and Units keys to set a continuous wave CW frequency or center frequency for a AF sweep FREQ INCR Key Used as a prefix to the Data and Units keys to set the step size for the FREQ INCREMENT W and sr Keys or the TUNE knob Pressing the FREQ INCR key recalls the current increment value to the FREQUENCY MHz display for as long as the key is depressed SHIFT Key Used as a prefix to obtain secondary functions of certain keys Keys containing shifted functions are labeled with that function in blue 4 RCUSTO Key Normal operation RCL Used as a prefix to a numeric key a single digit 0 9 to identity the storage register to recall the contents saved in that register RCLO is used to preset the front panel Refer to Simplified Operation in this section for a list of preset conditions Shifted function STO Used as a prefix to a numeric key a single digit 1 9 to identify the stora
87. ENT up and down keys or the TUNE knob The tuning increment size for both methods is equal to the frequency increment value except during manual sweep mode The sweep step size controls the tuning increment in manual sweep mode Tuning with the TUNE knob is useful for observing a range of frequencies and still being able to speed up or slow down the tuning as desired In addition the frequency increment may be decreased if finer resolution is desired around a specific frequency The TUNE knob can be disabled to avoid accidental changes in the set frequency The frequency increment step keys are very useful for tuning between channels with a fixed channel spacing Setting the frequency increment to the channel spacing allows easy stepping with a single key press In addition holding down the frequency increment step key will allow tuning at a rate of about ten steps per second This power tune feature does not offer as much control as the TUNE knob because the stepping rate is fixed for the frequency increment step keys The nine store recall registers of the Signal Generator allow up to nine different front panel settings to be stored and recalled This feature is useful when several unrelated frequencies are required Each register can be stored with the same frequency increment or different frequency increments depending on the application A simple two stroke key sequence will recall each register as needed To set the Signal Generator fr
88. FREQ INCREMENT control Swept signals from the instruments will be offset by the FREQ INCREMENT value In each sweep mode of operation the designated Slave Unit will have the MANUAL and SINGLE pushbutton lamps lit The designated Master Unit will have only the selected mode pushbutton lamp lit A step by step example follows a Interconnect two instruments for HP IB Designate one instrument as the Master Unit and set its HP IB Address to 50 Designate the other instrument as the Slave Unit and set its HP IB Address to 40 b On both units set SWEEP START to 6000 MHz and SWEEP STOP to 12000 MHz On both units set either the number of steps or step size to the desired value As one example set both master and slave units for 500 steps c On the Slave Unit select a 50 MHz offset using the FREQ INCR and the FREQ INCREMENT 3 or lt i to increase the Slave Unit frequency by 50 MHz 3 7 Operation Sweep Mode in Master Slave Configuration cont d d Press and hold SWEEP START on the Slave Unit and check for a 50 MHz offset Display should read 6050 MHz e For AUTO Mode Press AUTO on Master Unit Slave Unit will have MANUAL and SINGLE key indicators lit f For MANUAL Mode Press MANUAL on Master Unit Slave Unit will have MANUAL and SINGLE key indicators lit On Master Unit enable TUNE ON OFF Use the TUNE Knob of the Master Unit to tune both Master and Slave Units according to 3 8 HP 8673H STEP SIZE set
89. HEN 430 Expected Round_down Minimum error is round down 440 ELSE 450 Expected Round_up Minimum error is round up 460 END IF 470 END IF 480 SUBEND 3 146 HP 8673H Programming Example cont d Error Messages Operation Detailed Operating Instructions Stop Frequency Sweep conta The following program can be called to wait for a source settled indication from the Signal Generator The program will wait a maximum of 1 second before assuming the SOURCE SETTLED bit is not going to be set The status byte must be cleared with the CS program code before the frequency is set If the status byte is not cleared the SOURCE SETTLED bit may have been set by a previous command the bit is latched until the status byte is read or cleared 500 510 520 530 540 550 560 SUB Settled T_counter TIMEDATE In case no source settled Stat SPOLL 719 Serial poli IF TIMEDATE T_counter gt t THEN Done Default of 1 second IF NOT BIT Stat 3 THEN GOTO 520 Wait for set bit Done SUBEND Source is settled or 1 second has passed The following message numbers may be displayed when setting the sweep start frequency Each message is explained as it pertains to setting sweep start frequency For a more complete description of the messages see the MESSAGES detailed operating instructions 01 03 10 11 12 90 Entered frequency is not within the range of the Signal Generator Invalid multiplier entry for system co
90. Hz 1 95 GHz with low end overrange Option 618 has a frequency range of 5 4 to 18 0 GHz 18 6 GHz with high end overrange The output is leveled and calibrated from 8 dBm to 100 dBm depending on the frequency and options For additional information see Table 1 1 AM FM and pulse modulation modes can be selected Frequency output level modulation modes and all other functions except line switch can be remotely programmed via HP IB Long term frequency stability is dependent on the time base either an internal or external reference oscillator The internal crystal reference oscillator operates at 10 MHz while an external oscillator may operate at 5 or 10 MHz The output of the Signal Generator is exceptionally flat due to the action of the internal automatic leveling control ALC loop External drive signals are required for all modulation modes AM depth and FM deviation vary linearly with the applied external voltage Full scale modulation is attained with a 1 0 volt peak signal Pulse modulation is compatible with TTL levels Two ranges of AM depth can be selected 30 and 100 The front panel meter can be used to set AM depth Specified AM rates are from 20 Hz to 100 kHz Six ranges of FM deviation are selectable 0 03 0 1 0 3 1 3 and 10 MHz FM peak deviation can be set using the front panel meter At output frequencies below 6 6 GHz peak deviation is limited to 10 MHz or five times the modulation frequency whichev
91. Hz even though the sweep does not execute exactly 7 kHz steps If the step size is reduced to 1 kHz the Signal Generator will step by 2 kHz and then 0 kHz for a 1 kHz average step size in the 2 kHz resolution frequency band Sweeps from a higher frequency to a lower frequency can be accomplished by setting the start frequency higher than the stop frequency This combination results in a negative frequency span as indicated when the frequency span is displayed Negative frequency spans can only be entered by setting the start frequency higher than the stop frequency An Auto Peak operation is performed whenever the RF output frequency is more than 50 MHz from the frequency at which the last Auto Peak operation was performed The Auto Peak operation optimizes the Signal Generator performance at the current frequency The Auto Peak operation produces small changes in the RF output level as the peaking is performed For applications requiring fastest sweeps Auto Peak may be disabled However with Auto Peak disabled modulation performance and maximum output power may be degraded The time required for the Auto Peak operation is not included in the dwell time setting The automatic level control ALC bandwidth is increased when sweep mode is activated This provides fast response to switching transients when sweeping In addition activating sweep mode while amplitude modulating increases the usable AM bandwidth by about 250 times See the amplitude mod
92. Hz for the next step The overall affect is to change 14 kHz in two steps which is the same as two 7 kHz steps If the output frequency is reset to 6 GHz the tuning increment will be 7 kHz a multiple of the specified 1 kHz When tuning the frequency the time it takes to switch from one frequency to the next depends on the largest baseband lt 6 6 GHz frequency digit being changed Generally the smaller the digit being changed the shorter the switching time For example a change of 3 kHz the 1 kHz digit would be faster than a change of 3 GHz the 1 GHz digit Typical switching times by largest digit being changed for frequencies less than 6 6 GHz can be summarized as follows Changed Within 7 kHz 100 MHz 10 MHz 1 MHz 100 kHz 10 kHz 1 kHz Frequencies above 6 6 GHz are produced by multiplying the baseband 2 0 6 6 GHz frequency For frequency changes involving frequencies above 6 6 GHz the actual frequency digits being changed must be determined by dividing the frequency change by two 6 6 to 12 3 GHz or three 12 3 to 18 0 GHz The result will indicate which digits of the fundamental unmultiplied frequency will actually change The frequency switching time will depend only on which digits of the baseband frequency are changing For applications that require fastest execution the SOURCE SETTLED bit of the status byte can be used Once the bit is set after a frequency has been incremented or decremented the output i
93. IES PROVIDED HEREIN ARE BUYER S SOLE AND EXCLUSIVE REMEDIES HP SHALL NOT BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHETHER BASED ON CONTRACT TORT OR ANY OTHER LEGAL THEORY ASSISTANCE Product maintenance agreements and other customer assistance agreements are available for Hewlett Packard products For any assistance contact your nearest Hewlett Packard Sales and Service Office Addresses are provided at the back of this manual Manufacturer s Declaration r HP 8673H Herstellerbescheinigung Hiermit wird bescheinigt dass dieses Ger t Sys tem in bereinstimmung mit den Bestimmungen von Postverf gung 1046 84 funkenst rt ist Der Deutschen Bundespost wurde das Inverkehr bringen dieses Gerates Systems angezeigt und die Berechtigung zur berpr fung der Serie auf Ein haltung der Bestimmungen einger umt Zusatzinformation f r Mess und Testger te Werden Mess und Testger te mit ungeschirmten Kabeln und oder in offenen Messaufbauten ver wendet so ist vom Betreiber sicherzustellen dass die Funk Entst rbestimmungen unter Betriebs bedingungen an seiner Grundst cksgrenze ein gehalten werden Manufacturer s Declaration This is to certify that this product meets the radio frequency interference requirements of Directive FTZ 1046 1984 The German Bundespost has been notified that this equipment was put into circula tion and has been granted the rig
94. L DISPLA 2Y ADDRESS key on the front panel The current HP IB address will be displayed in decimal in the FREQUENCY MHz display g Replace the A2 Assembly s internal cover and the Signal Generator s top cover Replace the two plastic standoffs h Connect the line mains power cable to the Line Power Module and set the LINE switch to ON Front Panel HP IB Address Setting To set the Signal Generator s HP IB address from the front panel the FRONT PNL ENABLE switch on the HP IB address switch must be set to 1 To change the address from the front panel key in the desired address press the STO key then press the LOCAL key Refer to Remote Operation HP IB in Section 3 for additional information 2 8 Interconnections Interconnection data for the Hewlett Packard Interface Bus is provided in Figure 2 4 2 3 instaiiaoon 2 9 Mating Connectors HP IB Interface Connector The HP IB mating connector is shown in Figure 2 4 AUX Interface Connector The rear panel AUX control connector requires a male 114 pin MicroRibbon 57 Series connector The HP part number is 1251 0142 This connector is also available from Amphenol Oak Brook Illinois 60521 Interconnection data for the rear panel AUX control connector is provided in Figure 2 5 Coaxial Connectors Coaxial mating connectors used with the RF Output of the Signal Generator should be 50Q Type N male connectors 2 10 Frequency Reference Sensitivity Selection
95. MHz display is correct 3 Press the appropriate units key You may enter the frequency in GHz MHz or kHz Once the units key is pressed the displayed frequency will be adjusted to display MHz and the output frequency will be set If a sweep mode is active when CW frequency is entered the actual frequency displayed after pressing the units key will usually not be the entered frequency The FREQUENCY MHz display is used to display sweep information during sweep mode so the new CW frequency will not be displayed Setting the CW frequency during a sweep changes the sweep center frequency to the value entered The sweep will continue about the new CW center frequency Tuning the frequency will also move the sweep center frequency when in sweep mode To check the current CW center frequency during sweep press and hold the FREQUENCY key The FREQUENCY MHz display will display the CW frequency as long as the key is held The Signal Generator will return to the CW frequency when the sweep mode is turned off HP 8673H Remote Procedure Example Operation Detailed Operating Instructions Frequency CW cont a The Signal Generator accepts any frequency within its specified frequency range A bove 6 6 GHz the programmed frequency may be rounded by the Signal Generator to be compatible with the 2 or 3 kHz resolution at the programmed frequency see Comments The format of the remote programming follows the front panel key sequence To
96. Manual Changes Section 8 Service Additional copies of the Operating Manual or the Service Manual can be ordered separately through your nearest Hewlett Packard office 1 2 SPECIFICATIONS Instrument specifications are listed in Table 1 1 These specifications are the performance standards or limits against which the instrument may be tested Supplemental characteristics are listed in Table 1 2 Supplemental characteristics are not warranted specifications but are typical characteristics included as additional information for the user 1 3 SAFETY CONSIDERATIONS This product is a Safety Class I instrument that is one provided with a protective earth terminal The Signal Generator and all related documentation should be reviewed for familiarization with safety markings and instructions before operation Refer to the Safety Considerations page found at the beginning of this manual for a summary of the safety information Safety information for installation operation performance testing adjustment or service is found in appropriate places throughout this manual INFORMATION 1 4 MANUAL UPDATES Manual Updates provide information necessary to update the manual The Manual Update is identified by the manual print date and part number both of which appear on the manual title page 1 5 DESCRIPTION The HP 8673H Synthesized Signal Generator is available in two banded options Option 212 has a frequency range of 2 0 to 12 4 G
97. OPERATING MANUAL HP 8673H SYNTHESIZED SIGNAL GENERATOR 2 0 12 4 GHz 0 4 18 0 GHz HP Part No 08673 90119 C HEWLETT Edition1 E0489 HP Binder Part No 9282 1078 P PACKARD fl OPERATING MANUAL HP 8673H SYNTHESIZED SIGNAL GENERATOR 2 0 12 4 GHz 5 4 18 0 GHz Including Options 001 002 003 004 005 006 008 907 908 909 915 and 916 SERIAL NUMBERS Attached to the rear panel of the instrument is a serial number plate The serial number is in the form 0000A00000 The first four digits and the letter are the serial number prefix The last five digits are the suffix the prefix is the same for identical instruments it changes only when a configuration change is made to the instrument The suffix however is assigned sequentially and is different for each instrument This manual applies directly to instruments with serial numbers prefixed 2918A and above Cz HEWLETT PACKARD Copyright HEWLETT PACKARD COMPANY 1989 1501 PAGE MILL ROAD PALO ALTO CALIFORNIA U S A OPERATING MANUAL PART NO 08673 90119 Edition 1 E0489 HP Binder Part No 9282 1078 Operating Manual Microfiche Part No 08673 90120 HP 8673H Contents CONTENTS Page Page Section 1 Frequency Standard Selection 3 6 GENERAL INFORMATION Additional Operating Informat
98. P INVALID HP IB CODE HP IB DATA WITHOUT VALID PREFIX INVALID HP IB ADDRESS ENTRY TALK FUNCTION NOT PROPERLY SPECIFIED OUTPUT LEVEL OUT OF RANGE Messages 28 99 are service related errors Refer to Section 8 in the manual SERVICE CODE OUT OF RANGE AUTO PEAK FUNCTION RECALL CHECKSUM ERROR LOSS OF DATA ON POWER UP MEMORY TEST FAILURE ROM TEST FAILURE A2A10 RAM TEST FAILURE A2A10 RAM NOT FUNCTIONAL AT POWER UP HP 8673H Description Local Procedure Remote Procedure Operation Detailed Operating Instructions Multiplier Mode Display multiplier mode provides direct output frequency display of a system of instruments The system may be composed of the Signal Generator and a frequency multiplier or a combination of equipment that produces an integer multiple of the Signal Generator s RF output frequency By entering the multiplying factor the Signal Generator can be used to directly display and control the output of the system as long as a linear relationship exists between the Signal Generator RF output frequency and the output frequency of the system Once the multiplier is entered a front panel annunciator lights to indicate that the displayed frequency is not equal to the actual RF output frequency All frequencies except frequency offset will be displayed after being multiplied by the entered multiplier For example with a multiplier of 2 entered an actual RF output frequency of 6 GHz will be displayed as
99. P 8673H Example cont d Program Codes Comments Operation Detailed Operating Instructions Recall and Store Registers cont d 2 Press the number 1 on the numeric keypad The register is now filled with thecurrent instrument state Subsequent operations except re storing the register will not affect the settings in register 1 To recall the instrument state stored in register 1 1 Press the RCL key to indicate that the instrument state will be recalled from one of the ten registers 2 Press the number 1 on the numeric keypad The instrument will be set to the state that was stored in register 1 This recall is non destructive so recalling register 1 later will produce the same results as this step If a register is recalled that was originally stored during remote mode the VERNIER will not affect the output level This restriction is required to allow the storage and recall of instrument states in remote mode that include the VERNIER setting A register that is stored in local mode will preserve the local VERNIER setting Recall of the register in remote mode will use the same local level VERNIER setting Remote The programming string to store the current instrument state in register 1 is ST1 To recall the register at a later time the program string RC1 would be used Sending the program string RCO or IP will preset the instrument Storage Register Codes Program Description Program Description Program Desc
100. R S CHECKS Basic Functional Checks cont d Procedure 22 Set FREQ INCR to 10 MHz Then set the outputlevel to the values shown in the cont d following table Tune from the corresponding start frequency to the stop frequency for each output level Verify that the indicated power level on the meter remains constant and stable and that the UNLEVELED annunciator remains off This ensures that the instrument can generate specified output power and remain leveled OPTION 212 OR 618 ONLY Range Vernier sun J Stop 2 dBm 2 00 GHz 12 40 GHz 2 dBm 5 40 GHz 18 00 GHz sit p so 0 dBm 2 00 GHz 12 40 GHz OdBm 5 40 GHz 18 00 GHz 12 40 GHz 18 00 GHz dBm 2 00 GHz 12 40 GHz l dBm 5 40 GHz 18 00 GHz Sweep Check The FREQUENCY MHz display is used to check the ability of the Signal Generator to SWEEP 3 20 HP 8673H Operation OPERATOR S CHECKS Basic Functional Checks cont d Procedure 23 cont d 24 25 26 27 28 29 30 Press RCL 0 to set the instrument to a known state Then press the AUTO s weep key Verify that the FREQUENCY MHz display now shows a start frequency of 8000 000 MHz and a stop frequency of 10 000 000 MHz The AUTO key indicator should flash once each time a new sweep begins Press SWEEP OFF Verify that the FREQUENCY MHz display returns to 9000 000 MHz Press the MANUAL sweep key The FREQUENCY MHz display should show 8000 000 MHz Tune the frequency up by turnin
101. RF output is to be used in a measurement Once the SOURCE SETTLED bit is set after sending the program code K1 Auto Peak On the RF output is settled and the Auto Peak operation is finished 3 71 Operation HP 8673H Detailed Operating Instructions Frequency CW conta Programming The following programs are written in BASIC for HP 9000 Series 200 or 300 controllers The Example following program is used to set the Signal Generator to the frequency specified by the variable called Expected The desired value must be in MHz and should be within the frequency range of the Signal Generator 10 SUB Freq_set Err Expected Expected frequency in MHz 20 OUTPUT 719 USING 2A MG Read message from 8673 30 ENTER 719 USING 2A Message to clear any old messages 40 Frequency iNT Expected 1000 1000 Round off to nearest kHz 50 OUTPUT 719 USING 4A 5D DDD 2A CSFR Frequency MZ Update status 60 CALL Settled Wait for source to settle 70 OUTPUT 719 USING 2A MG Check for message from 8673 80 ENTER 719 USING 2A Message 90 SELECT VAL Message 100 CASE 1 Frequency was out of range 110 Erret 120 DISP WARNING Attempt to set frequency out of range 130 CASE 90 Auto Peak Error 140 Err 90 150 DISP WARNING Auto Peak error Service may be required 160 CASE ELSE 170 Err 0 Other errors not applicable 180 END SELECT 190 200 OUTPUT 719 USING 2A OK Requests current frequency 210 ENTER 719 USING
102. S Program codes are typically 2 character mnemonics All codes normally used by the operator to control the Signal Generator are given in Table 3 6 HP IB Program Codes Numeric values are either a single decimal digit a set of 11 characters or less representing a number or a string of binary bytes A string of 11 characters maximum can be expressed in decimal form only Digits beyond the front panel display capability of a particular parameter are truncated Therefore it is best to format the data so that it is rounded to the correct number of digits Units terminators are 2 character codes that terminate and scale the associated numeric value Frequency can be entered in GHz MHz kHz or Hz Sweep time values are entered in milliseconds Power values are entered in dB End of String messages EOS can be the ASCII characters Line Feed LF semicolon or the bus END message that is bus lines EOI true and ATN false The at sign acts as an EOS when the Signal Generator is in the Deferred Execution mode HP 8673H Receiving Data Messages cont d Valid Characters The ASCII characters used for program strings are A Z a z 0O 9 LF The alpha program codes can be either upper or lower case since the Signal Generator will accept either type they can be interchanged Spaces unnecessary signs leading zeros and carriage returns CR are ignored However if a space or other such character were
103. Signal Generator front panel 3 Press the shift key and then the SYSTEM key shifted DIODE With the Signal Generator range set to 0 dB and above the output level of the amplifier can be directly controlled using the RANGE and VERNIER Remote 1 Perform the above steps 1 to 3 to connect the system 2 The controller can now directly set and read the output level of the RF amplifier by setting the Signal Generator output level to the desired level 3 149 Operation HP 8673H Detailed Operating Instructions System Automatic Level Control conta Program Description Code C4 External System Leveling Mode SHC2 Comments Using external system leveling mode has the advantages of no calibration required built in temperature compensation direct control of the leveled RF signal and an extra range for high power applications The dynamic range available is dependent only on the signal path gain and losses Amplitude modulation up to 90 depth at rates as high as 80 kHz is typically available using system leveling mode Program Codes The external ALC circuitry is used to adjust the Signal Generator s output level until the detected voltage at the external ALC input is correct If high harmonics or spurious signals are present in the signal that is being detected they will affect level flatness This is especially important when using external amplifiers and mixers within the signal path The actual magnitude of the error introduced is
104. T UPC TRIM Mode 40 CASE NORM NORMAL 50 Code P2 Cade for NORMAL mode 60 CASE COMP COMPLEMENT 70 Code P3 Code for COMPLEMENT mode 80 CASE OFF 90 Code P0 100 CASE ELSE 110 Erra 1 120 DISP Invalid pulse mode specified 130 END SELECT 150 OUTPUT 719 USING 2A Code 170 SUBEND The following message number may be displayed when pulse modulating For amore complete description of the message see the MESSAGES detailed operating instructions 90 An error occurred in the Auto Peak operation Service may be required to correct the problem HP 8673H Description Local Procedure Remote Procedure Operation Detailed Operating Instructions Range Output Level The RF output level of the Signal Generator is set using the RANGE and VERNIER controls The RANGE controls change the RF output level in 10 dB steps and the VERNIER changes the RF output level continuously over a 13 dB range The sum of the output level RANGE and VERNIER is the actual RF output level The RANGE is set using the RANGE up or down key The selected RANGE 10 to 90 is displayed in the RANGE dB display The display indicates the RANGE whether in remote or local mode The local to remote and remote to local transitions do not change the output level RANGE An instrument preset will set the RANGE to 70 dB To set the RF output level using internal ALC 1 Press the RANGE up or down key until the desired RANGE appear
105. TTING THE FRONT PANEL FOR SYSTEM MODE Press rex to invoke an alternate set of preset conditions more suitable for system mode System mode enables the Signal Generator to control a compatible external amplifier multiplier etc These preset conditions are shown below RF OUTPUT to ON OFFSET 0 MULTIPLIER unchanged RANGE to 70 dB except Options 001 and 005 RANGE to 0 dB for Options 001 and 005 AUTO PEAK to ON Meter Scale to LVL FREQUENCY to 11 000 000 MHz x multiplier Option 212 FREQUENCY to 14 000 000 MHz x multiplier Option 618 FREQ INCR to 1 000 MHz x multiplier START to 10 000 000 MHz x multiplier Option 212 START to 13 000 000 MHz x multiplier Option 618 STOP to 12 000 000 MHz x multiplier Option 212 STOP to 15 000 000 MHz x multiplier Option 618 AF to 2 000 000 MHz x multiplier MKRS to OFF initialized to 7 8 9 10 and 11 GHz x multiplier SWEEP MODE to OFF STEP to 100 steps 20 000 MHz x multiplier DWELL to 20 ms i TUNE knob to ON ALC mode unchanged 1 SETTING FREQUENCY IN SYSTEM MODE OFFSET amp MULTIPLIER The SYSTEM FREQ shifted SWEEP FREQ keys are used to enter and display offset or mu frequencies For use with extemal devices such as multipliers mixers etc OFFSET To set an offset of or 10 MHz for example for use with an external mixer press SHIFT OFFSET OFFSET OOO The entered and displayed frequency is 10 MHz above or below the Signal Generator s actual output frequency
106. The OVEN COLD annunciator may flicker off and on temporarily just as the oven stabilization temperature is reached This is normal operation Once the OVEN COLD status annunciator is off set the LINE switch to ON Operation HP 8673H OPERATOR S CHECKS Basic Functional Checks cont d Procedure cont d NOTE If the MESSAGE key indicator is on or flashing the instrument self diagnostics detected a malfunction during turn on Press and hold the MESSAGE key to display the message code in the FREQUENCY MHz display Any code other than 00 represents an error Refer to Table 3 8 for a complete listing of message codes and the malfunctions they represent Occasionally due to line transients or other external conditions the instrument self diagnostics may indicate a false error Pressing the MESSAGE key and repeating the turn on procedure will usually differentiate between real and false errors Errors that repeat are real 6 Set the FREQ STANDARD INT EXT switch to EXT Verify that the EXT REF and UNLOCKED status annunciators turn on Set the switch back to INT The status annunciators should then turn off Press RCL 0 Verify that the instrument is now preset to the following conditions RF OUTPUT to ON ALC mode to INTERNAL OUTPUT LEVEL RANGE to 70 dBm 0 dB for Option 004 and 005 AUTO PEAK to ON Meter scale to LVL AM FM and Pulse Modulation to OFF FREQUENCY to 9000 000 MHz FREQ INCR to 1 000 MHz START to 8000 0
107. The disadvantage of power meter leveling is the longer settling time 0 2 to 6 seconds 23 dB of dynamic range is typically available using the Signal Generator s 0 and 10 dB ranges In addition amplitude modulation up to 90 depth at rates as high as 100 kHz is typically available using external power meter leveling mode since the Signal Generator s internal detector is used to provide the AM detection The response time for a level change using power meter leveling mode will vary depending on the type of power meter the power meter range setting and filter setting if used of the power meter Settling time increases as the sensitivity of the range used increases In addition the response to a level change can be underdamped critically damped or overdamped depending on the type of meter and filter selection Typical 99 settling times for the HP 436A HP 437B and HP 438A power meters are shown in the following table The 99 settling time is the time the power meter requires to make a measurement in a given range 3 107 Operation HP 8673H Detailed Operating Instructions Comments cont d 3 108 Power Meter Automatic Level Control conta Power Meter Range Settling Times Typ 99 Settling HP 437B HP 438A HP 436A The leveling system will have a longer settling time due to the settling time of the Signal Generator ALC circuitry and the response time of the signal path Typical settling times for leveli
108. UT 719 KO OUTPUT 719 K0 PEAK off Operator s Check that the Signal Generators AUTO PEAK key indicator is off Response Send the Clear message turning the Signal CLEAR 719 CLEAR 719 Generator s AUTO PEAK function on Operator s Check that the Signal Gene rator s AUTO PEAK key indicator is on Response Abort Message Note This check determines if the Signal Generator becomes unaddressed when it receives the Abort message This check assumes that the Signal Generator is in the remote mode Series 200 300 HP 85B BASIC OUTPUT 719 OUTPUT 719 Description Address the Signal Generator to listen Operator s Check that the Signal Generators LSN and RMT annunciators are on Response Send the Abort message unaddressing the ABORT 7 ABORTIO 7 Signal Generator from listening Operator s Check that the Signal Generators LSN annunciator is off but the RMT annunciator is on Response Status Byte Message Note This check determines if the Signal Generator sends the Status Byte message Before beginning this check turn the Signal Generator s LINE switch to STBY then to ON 3 28 HP 8673H Operation gt OPERATOR S CHECKS HP IB Functional Checks cont d Status Byte Message cont d Description Series 200 300 HP 85B BASIC Operator s Response Place the Signal Generator in serial poll SPOLL 719 SPOLL 719 mode causing it to send the Status Byte message The controller s di
109. a downconverter process the frequency offset can be set to the intermediate frequency IF Once the offset is set setting both the RF and the local oscillator to the same frequency will produce an IF frequency that is equal to the entered offset Using the frequency offset in conjunction with the multiplier mode is useful for harmonic mixing applications In harmonic mixing a harmonic of the local oscillator is used to downconvert a signal near the harmonic frequency Setting the multiplier equal to the harmonic and then entering a frequency offset equal to the desired offset enables the local oscillator to be set to the frequency of the signal to be downconverted The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The following program is used to set the frequency offset to the offset specified by the variable called Expected The offset can be positive or negative and must be in units of MHz 10 SUB Offset_freq Err Expected 20 30 OUTPUT 719 USING 2A MG l Clear any old messages 40 ENTER 719 USING 2A Message 50 60 OUTPUT 719 USING 2A 5D DDD 2A FT Expected MZ 701 80 OUTPUT 719 USING 2A MG Check for errors 90 ENTER 719 USING 2A Message 100 SELECT VAL Message 110 CASE1 120 Err 1 130 DISP ERROR Offset frequency is out of range 140 CASE ELSE 150 Err 0 160 END SELECT 170 180 OUTPUT 719 USING 4A FTOA Read offset back 190 ENTER 719 USING K O
110. ages 40 OUTPUT 719 USING 2A DDDD 2A SP Expected SS Set size 50 OUTPUT 719 USING 2A MG l Get any error message 60 ENTER 719 USING 2A Message 70 SELECT VAL Message 80 CASE 90 Err 1 100 DISP WARNING The number of steps is out of range 110 CASE ELSE 120 Err 0 130 END SELECT 140 150 SUBEND The following message numbers may be displayed when setting the number of steps Each message is explained as it pertains to setting the number of steps For a more complete description of the messages see the MESSAGES detailed operating instructions 07 The entered number of steps is less than 1 or greater than 9999 13 The number of steps was adjusted to achieve a step size that is equal to or greater than the specified resolution This adjustment also occurs when the selected number of steps would produce a sweep step size that is not a multiple of the 1 kHz minimum frequency resolution For example a frequency span of 350 kHz with 140 steps would require a 2 5 kHz step size The Signal Generator would use 175 steps of 2 kHz to produce a step size that is a multiple of 1 kHz 3 139 Operation HP 8673H Detailed Operating Instructions Description Local Procedure Remote Procedure Step Size Sweep The Signal Generator performs a sweep by stepping the RF output frequency in discrete steps between the start and stop frequency of the sweep The number of steps that the Signal Generator makes between
111. alue Setting the sweep center frequency will automatically reset the sweep start and stop frequencies to the required values The sweep step size will also be recalculated by dividing the sweep delta frequency by the current number of steps Resetting the start or stop frequency will reset the sweep delta frequency and will reset the sweep center frequency if a sweep mode is enabled or the CW frequency if sweep is off Changing the sweep center frequency has the effect of changing the start and stop frequencies by the same value The sweep center frequency can be set to any valid frequency within the Signal Generator s frequency range To set the Signal Generator to a specific sweep center frequency 1 Press the FREQUENCY key to indicate that the next entry will be for sweep center frequency This procedure is identical to the setting of CW frequency The Signal Generator always sets the CW frequency equal to the entered sweep center frequency when sweep mode is turned off When sweep modes are on CW frequency entries also reset the sweep center frequency to the same value 2 Enter the desired frequency using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue entering the correct digits until the frequency displayed in the FREQUENCY MHz display is correct 3 Press the appropriate units key You may enter the frequency in GHz MHz or kHz Once the
112. amming 80 ENTER 719 USING 2A Message Example 90 SELECT VAL Message cont d 100 CASE 1 Frequency was out of range 110 Err t 120 DISP WARNING Attempt to set sweep stop frequency out of range 130 CASE 10 140 Err 10 150 DISP WARNING Sweep start and stop frequency are equal 160 CASE 90 Auto Peak Error 170 Err 90 180 DISP WARNING Auto Peak error Service may be required 190 CASE ELSE 200 Err 0 l Other errors not applicable 210 END SELECT 220 230 OUTPUT 719 USING 4A FBOA Requests current stop freq 240 ENTER 719 USING K Set_freq Frequency in Hz 250 Set_freq INT Set_freq 1000 1000 Convert to MHz 260 270 IF ABS Set_freq Frequency gt 001 AND Err 0 THEN 280 DISP WARNING Requested frequency rounded to Set_freq 280 ENDIF 285 SUBEND End of subroutine To prevent roundoff errors from occurring the following subprogram may be used to adjust a frequency so that it is always within 1 kHz of the desired frequency 300 SUB Round_off Err Expected Expected frequency in MHz 310 Err 0 Initialize Err 320 Band 5 330 340 IF Expected lt 18600 001 THEN Band 3 350 IF Expected lt 12300 001 THEN Band 2 360 IF Expected lt 6600 001 THEN Band 1 370 380 Baseband INT Expected 1000 Band 1000 Rounded fundamental 380 Round_down Baseband Band 400 IF Round_down lt gt Expected THEN Requires rounding 410 Round_up Baseband 001 Band 420 IF ABS Round_down Expected lt ABS Round _up Expected T
113. are set whenever a valid condition exits The only way to clear a bit that has been set is to clear the status bytes with a CS program code or to read the extended status byte Once the extended status byte is read it will be cleared and updated Note that the bits are not cleared until after the extended status is read To read the current instrument extended status the program string CSOS should be sent to clear both status bytes and to update the extended status byte The extended status byte is composed of eight bits with each bit defined as follows 3 131 Operation HP 8673H Detailed Operating Instructions Description cont d Local Procedure Remote Procedure 3 132 Status Byte and Polling conta BIT1 SELF TEST FAILED When the Signal Generator is first turned on a self test is performed to check the instrument s Digital Control Unit If a failure is detected the SELF TEST FAILED bit is set BIT2 FM OVERMOD If the FM circuitry is overmodulated by applying more than one volt peak at the input or by exceeding the instrument capability the FM OVERMOD front panel annunciator and status bit will be set BIT 3 This bit is always set to zero BIT4 EXTERNAL REF When the Signal Generator s rear panel panel FREQ STANDARD INT EXT switch is set to EXT the front panel EXT REF annunciator and the EXTERNAL REF status bit will be set BIT5 NOT PHASE LOCKED If the Signal Generator is not phase locked due to instrument
114. arker in remote mode is done using the letter M followed by the marker number For example M1 specifies marker 1 Deactivating ail markers is done by specifying marker zero M0 Deactivating a single marker is done by specifying a marker and then sending the program code MO Marker Off Activating a marker is done by specifying a marker For example the program string M5 will activate marker 5 To set the marker to a specific frequency the marker is specified and then the frequency is specified with the appropriate units terminator GZ MZ KZ or HZ The sweep marker frequency can be read for any given marker by specifying the marker followed by the output active program suffix The Signal Generator will send the frequency in fundamental Hz units If the marker frequency is read as a string the format will be the program code MK followed by the marker frequency in Hz and then the units terminator Hz To set marker 3 to 12 34 GHz Local 1 Press the MKR key 2 Key in3 using the numeric keypad This indicates that marker 3 is to be acted upon by the next entry and activates marker number three Note that the FREQUENCY MHz display shows the current sweep marker frequency when the 3 is pressed 3 Key in 12 34 using the numeric keypad The FREQUENCY MHz display should show 12 34 and should be left justified 4 Press the GHz units key to finish the sequence The FREQUENCY MHz display should display the entered frequency in MHz and sh
115. arkers are set to the same sweep marker frequency For example if two markers are set for 7 GHz and 7 GHz is also a valid point in the frequency sweep three sweep points will be generated at 7 GHz See the comments section for more details on marker priority and marker frequency points To set and activate a sweep frequency marker 1 Press the MKR key to indicate that a marker will be set activated or turned off 2 Enter the marker number that is to be set using the numeric keypad Valid marker numbers are one through five 3 Enter the desired marker frequency using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue entering the correct digits until the frequency displayed in the FREQUENCY MHz display is correct 4 Press the appropriate units key The frequency may be entered in GHz MHz or kHz Once the units key is pressed the displayed frequency will be adjusted to display MHz and the sweep marker frequency will be displayed until the units key is released Setting the sweep marker frequency will activate the sweep marker If the sweep marker frequency is between the sweep start and stop frequency pressing the MKR key will display the marker number to indicate that it is active If the sweep marker frequency is not between the sweep start and stop frequency it will not be displayed as active until the start or stop frequencies are reset to place
116. art of the HP 11726A Support Kit it can be ordered separately through the nearest Hewlett Packard office The HP 11726A Support Kit is available for maintaining and servicing the Signal Generator It consists of cables adapters termination and prerecorded programs extender boards and test extender boards The HP 8116A Pulse Function Generator is adequate for modulating the Signal Generator and meeting stated standards This remotely programmable signal source is convenient for full remote control of modulation levels and rates The Synthesizer Interface Cable part number 5061 5391 provides an interface to the HP 8349B Microwave Amplifier This provides calibrated output level under control of the system compatible Signal Generator This cable as well as the HP 8349B Microwave Amplifier is required for use with the HP 83550 family of frequency multipliers For more information see paragraph 3 2 System Compatibility 1 13 RECOMMENDED TEST EQUIPMENT Table 1 3 lists the test equipment recommended for testing adjusting and servicing the Signal Generator Table 1 4 lists the test equipment recommended for Abbreviated Performance Tests Essential requirements for each piece of test equipment are described in the Critical Specifications column Other equipment can be substituted if it meets or exceeds the critical specifications General nformauon HP 8673H Table 1 1 Specifications 1 of 6 Note Specifications apply
117. ata Message Note This check determines if the Signal Generator properly receives Data messages Description Serles 200 300 HP 85B BASIC Send the first part of the Remote message REMOTE 7 enabling the Signal Generator to remote Address the Signal Generator to listen completing the Remote message then send a Data message OUTPUT 719 FR11GZ OUTPUT 719 FR11GZ Operator s The Signal Generator should be set to 11 GHz Response Sending the Data Message Note This check determines if the Signal Generator properly issues Data messages when addressed to talk Before beginning this check turn the Signal Generator s LINE switch to STBY then to ON Then key in RCL 0 to preset the instrument If a series 200 300 controller is used a short program is required to perform the check _ 3 26 HP 8673H Operation SPE d OPERATOR S CHECKS HP IB Functional Checks cont d Sending the Data Message cont d Description HP 85B BASIC Send the Remote message 10 REMOTE 719 REMOTE 719 Send a Data message causing Generator 20 OUTPUT 719 OK OUTPUT 719 OK to output its lock frequency Address the Generator to talk and store its 30 ENTER 719 V ENTER 719 V output in variable V Display the value of V 40 DISP V DISP V 50 END Operator s Check that the Signal Generator s TLK annunciator is on The controller s display should read Response 9 E 9 series 200 300 or 9000000000 HP 85B
118. ay is correct 3 Press the appropriate units key You may enter the sweep step size in GHz MHz or kHz Once the units key is pressed the sweep step size will be adjusted to read in MHz and the sweep Step size will continue to be displayed until the units key is released If the entered value does not result in at least one step and less than 9999 steps the step size will be adjusted until the Signal Generator is capable of performing the sweep The entered value is retained for use when other sweep parameters are changed This feature enables the sweep parameters to be entered in any order with restrictions due to previous sweep parameters not affecting the final values For example if the sweep step size is entered as 1 GHz with the current sweep span defined as 100 kHz the sweep step size will be adjusted to be 100 kHz and a message will be issued However changing the sweep span to 10 GHz will restore the sweep step size to 1 GHz without having to re enter the value The Signal Generator accepts any sweep step size within the range of 1 kHz and the maximum frequency of the Signal Generator Any digits below 1 kHz will be truncated and the entered value may be adjusted to be consistent with the remaining sweep parameters The format of the remote programming follows the front panel key sequence The program code SS or SP is sent followed by the desired sweep step size and the units GHz MHz kHz or Hz HP 8673H Remote Procedure co
119. be done in one of two ways The RF output level can be programmed directly using the program code LE AP or PL The units terminator for the output level is dBm which corresponds to the program code DM The Signal Generator will also accept the program code DB as the terminator When programming the RF output level the VERNIER is set between 0 and 9 9 dBm and the RANGE is set accordingly 3 151 a Operation HP 8673H Detailed Operating Instructions Remote Procedure cont d Example 3 152 Vernier Output Level conta The RF output level can also be programmed by programming the VERNIER and the RANGE separately The program code to set the RANGE is R A and the program code to setthe VERNIER is VE The units terminator for both codes can be either DB or DM The output active program code suffix can be used to read the current values of the RANGE VERNIER or the RF output level directly To read the RANGE setting send the program codes RAOA and then read the RANGE setting The Signal Generator will send the RANGE in fundamental dBm units If the RANGE is read as a string the format will be the program code RA foilowed by the RANGE in dBm and then the units terminator DM dBm In local mode the Signal Generator keeps track of the VERNIER setting to within 0 1 dB When switching to remote mode the local RF level setting is preserved This feature also allows the controller to read the local VERNIER setting by briefly s
120. bytes Output Request Mask in binary Output status and extended status bytes in binary Prefix to set Request Mask in binary Prefix to set Request Mask in binary Entry End of Error Sweep Complete Pressed in Sweep Request Parame Service EXTENDED STATUS BYTE 8 RR See i s er eal o ee 64 s2 Joas s qal Ref always ters always leveled When using the status byte to monitor the results of program strings care must be taken to avoid incorrect results When the instrument is preset and the frequency and or level do not change the SOURCE SETTLED bit will be set before the extended status byte is set In addition some conditions may cause bits in the extended status byte to not be set For maximum assurance that the instrument is settled and the extended status byte is valid after a preset the following procedure should be used HP 8673H Comments cont d Programming Example Operation Detailed Operating Instructions Status Byte and Polling conta 1 Set the Signal Generator to 9 GHz and then preset the instrument with the program string FR9GZRCO 2 Monitor the status byte using a serial poll until the SOURCE SETTLED bit is set 3 Clear the status and prepare the extended status byte with the program string CSOS If the above procedure is followed the extended status byte will be valid and the preset will be comp
121. ch and the HP IB Section 2 Installation also shows the pinout address configuration of the AUX connector as well as information for a recommended mating A quick test of the Signal Generator s HP IB interface connector is described earlier in this section under Remote Table 3 2 AUX Connector Functions 1 Recall 1 Recalls the contents of internal storage register 1 Recali Next FREQ INCREMENT Up FREQ INCREMENT Down Sequential recall of internal storage registers 2 through 9 Same as FREQ INCREMENT Up key Same as FREQ INCREMENT Down key Same as SINGLE key Trigger Single Sweep Service Same as internal service switch on A2A2 Key Code Assembly Refer to Section 8 Service Stop Sweep Stops sweep Sweep resumes when this line goes high No Display Blanks FREQUENCY MHz display when this pin is grounded and the existing display changes Negative Blanking 5V for blanking Trigger One pulse when the Signal Generator has made a frequency change that may cause loss of phase lock to an instrument tracking the Signal Generator End of Sweep One pulse at end of each sweep 3 32 HP 8673H REMOTE OPERATION 4 cont d Operator s Checks These checks verify that the Signal Generator can respond to or send each of the applicable bus messages described in Table 3 3 3 24 HP IB Compatibility The Signal Generator has a three state TTL HP IB interface which can be use
122. cted in the signal path with feedback from the last component in the signal path generating a system feedback voltage that is 0 volts at 0 dBm and has a sensitivity of 30 millivolts dB into a 50 ohin load The advantages of system leveling are automatic calibration to the Signal Generator s level meter temperature compensation built into the Signal Generator and the addition of a 20 dBm range to be used with external amplifiers When used with a 2 to 20 GHz amplifier the maximum leveled power of the Signal Generator can be as high as 23 dBm i To set the Signal Generator for extemal system leveling 1 Connect the external equipment to the Signal Generator with the component generating the system feedback voltage at the end of the signal path 2 Press the Signal Generator s shift key and then press the SYSTEM key shifted DIODE key This sets the Signal Generator to system leveling mode which is indicated by the ALC INT key and the SYSTEM key being lighted See paragraph 3 2 System Compatibility 3 Reset the Signal Generator range to at least 10 dB above the range required for the desired RF output level The range may have to be adjusted to compensate for losses and gains in the RF signal path If the RF signal path will have a relatively high loss a higher Signal Generator range will be required 4 Connect the system feedback voltage to the external ALC input of the Signal Generator No calibration is required on the Signal Genera
123. cy and end at the stop frequency Setting the center frequency and frequency span will start the sweep at one half the frequency span below the center frequency and end the sweep at one half the frequency span above the center frequency Setting the CW frequency when sweep is off will also reset the sweep center frequency to the same value Setting the center frequency or frequency span will automatically recalculate the appropriate sweep start and stop frequencies Resetting the sweep start or stop frequency will reset the sweep center frequency if in sweep mode or the CW frequency if sweep is off The frequency span will be recalculated whether sweep is on or off The sweep center frequency or CW frequency will be reset to be halfway between the start and stop frequencies The sweep start frequency can be set to any valid Signal Generator frequency In addition if the start frequency is set above the stop frequency single and auto sweep modes will still sweep from the start to the stop frequency Manual sweep will start at the lower absolute frequency and move toward the higher absolute frequency To set the Signal Generator to a specific sweep start frequency 1 Press the SWEEP FREQ START key to indicate that the next entry will be for sweep start frequency 2 Enter the desired frequency using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue enteri
124. cycle too long between pulses are indicated by the UNLEVELED annunciator The overmodulation condition can be read by the controller using the ALC UNLEVELED bit of the extended status byte Major pulse modulation specifications are not warranted unless an Auto Peak operation has been performed An Auto Peak operation is performed automatically whenever the frequency is changed by more than 50 MHz while Auto Peak is enabled or the output level is changed by more than 0 4 dB while pulse modulation is enabled Changes in load impedance can shift the center frequency of internal filters and require an Auto Peak operation to maintain optimum pulse performance This could occur if highly reactive loads are switched in and out in automatic test systems Large frequency changes cause changes in the self heating of internal Yttrium Iron Garnet CYIG filters Most of the filter passband drift occurs in 15 to 20 seconds but complete settling can require up to 15 minutes Some experimentation may be required to determine when the Auto Peak operation should be performed during measurements that have large frequency changes and extremely long measurement cycles To ensure that pulse performance is optimized before making a measurement execute an Auto Peak operation before each measurement The status byte may be monitored to determine when the Auto Peak operation is complete The SOURCE SETTLED bit is set when the Auto Peak operation is finished The Signal
125. d EXT REF lights when the rear panel INT EXT switch is in the EXT position 6 MESSAGE Key Lights to indicate entry errors and flashes to indicate hardware malfunctions A two digit code appears in the FREQUENCY MHz display when this key is pressed Refer to the Messages Detailed Operating Instruction for an explanation of the codes FREQUENCY MHz Display Normally indicates output frequency Message codes and previously set values for FREQ INCR SWEEP FREQ and SWEEP RATE functions are displayed for as long as their respective keys are pressed HP IB STATUS Annunciators Indicate the status of the Signal Generator when it is operating via the HP IB RMT lights when the Signal Generator is in remote mode LSN lights when the Signal Generator is addressed to listen TLK lights when the Signal Generator is addressed to talk SRQ lights when the Signal Generator is issuing the Require Service message Figure 3 2 Displays and Status Annunciators 3 9 Operation 9 RF OUTPUT Connector 50N Type N female connector supplies RF output over the entire frequency range of 2 to 12 4 GHz Option 212 or 5 4 to 18 0 GHz Option 618 RF OUTPUT ON OFF Key Completely turns off the RF output when set to OFF Setting the RF output to OFF causes the sUNLOCKED and UNLEVELED status annunciators to light When the RF OUTPUT is set to ON the Signal Generator returns to normal operation INTERNAL Key Select
126. d Fall Times Minimum Leveled RF Pulse Width Pulse Repetition Frequency Minimum Duty Cycle Minimum Pulse Off Time Maximum Peak Power Peak Level Accuracy Overshoot Ringing AMPLITUDE MODULATION Depth 1 75 dB 1 50 dB 2 10 dB 2 30 dB 2 70 dB 2 70 dB plus 0 2 dB per 10 dB step below 30 dBm Add 0 75 dB to remote programming absolute level accuracy 0 1 dB 0 75 dB 1 00 dB 1 25 dB gt 80 dB lt 35 ns lt 100 ns de to 1 MHz lt 0 0001 lt 300 ns Same as in CW mode 1 5 dB 1 0 dB lt 20 lt 25 10 dBm output level range 0 dBm output level range 10 dBm output level range 20 dBm output level range 30 dBm output level range lt 30 dBm output range Absolute level accuracy specifications include allowances for detector linearity temperature flatness attenuator accuracy meter accuracy and measurement uncertainty 0 dBm range 15 to 35 C 2 0 to 6 6 GHz 2 0 to 12 3 GHz 2 0 to 18 0 GHz Min to max variation in power level across specified frequency limits is less than 2 times flatness spec AUTO PEAK enabled When internally leveled no restriction when unleveled Relative to CW 15 to 35 C 2 0 to 6 6 and 6 7 to 18 0 GHz 6 6 to 6 7 GHz 15 to 35 C 2 0 to 18 0 GHz 0 dBm maximum carrier level Fir OUs JIL Table 1 1 Specifications 4 of 6 Woncias siuiiu auul Electrical Characteristics Performance Limits Conditions AMPLITUDE MODULATION
127. d of 12 4 GHz The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The following program is used to set the Signal Generator to the sweep delta frequency specified by the variable Expected The desired value must be in MHz and should be between 1 kHz and the maximum frequency of the Signal Generator 10 SUB Sweep_deita_set Err Expected Expected frequency in MHz 20 OUTPUT 719 USING 2A MG Read message from 8673 30 ENTER 719 USING 2A Message lto clear any old messages 40 OUTPUT 719 USING 4A 5D 0DD 2A CSDF Expected MZ Update status 50 OUTPUT 719 USING 2A MG Check for message from 8673 60 ENTER 719 USING 2A Message 70 SELECT VAL Message 80 CASE 1 Frequency was out of range 90 Erret 100 DISP WARNING Attempt to set sweep delta frequency out of range 110 CASE 11 120 Err 11 130 DISP WARNING Sweep start frequency adjusted to be in range 140 CASE 12 Auto Peak Error 150 Err 12 160 DISP WARNING Sweep stop frequency adjusted to be in range 170 CASE ELSE 180 Err 0 Other errors not applicable 190 END SELECT 200 210 OUTPUT 719 USING 4A DFOA Requests current delta freq 220 ENTER 719 USING K Set_freq Frequency in Hz 230 240 IF Set_freq lt gt Expected THEN 250 DISP WARNING Error in programmed delta frequency 260 ENDIF 270 SUBEND End of subroutine HP 8673H Error Messages Operation Detailed Operating Instructions Delta Freque
128. d the number of Steps must be read Since step size and the number of Steps are directly related both are sent when the output active program code suffix is used If read as a string the format is the program code SP followed by the sweep step size in fundamental units Hz the units terminator Hz a comma the program code SP followed by the current number of steps and the units terminator SS To set the number of sweep steps to 350 steps Local 1 Press the STEP key 2 Key in 350 using the numeric keypad The FREQUENCY MHz display should show 350 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the STEP units key to finish the sequence The FREQUENCY MHz display should show the entered or adjusted number of steps on the left half of the display and the calculated sweep step size on the right half of the display The message key will light if the number of steps are adjusted to indicate the change from the desired value Remote The programming string for setting the number of Sweep steps is composed of a program code numeric data and the units terminator To program the number of steps to 350 steps the program string is SP350SS The program codes SS and SP can be used interchangeably in the above program string The alpha characters can be sent as upper or lower case or even mixed upper and lower case Program Function Applicable Code Units SP Number of Sweep Ste
129. d with any HP IB computing controller or computer for automatic system applications The Signal Generator is programmable via the HP Interface Bus Its programming capability is described by the twelve HP IB messages listed in Table 3 3 The Signal Generator s compatibility with HP IB is further defined by the following list of interface functions SH1 AH1 T5 TEO L3 LEO SR1 RL1 PP1 DC1 DT1 and CO A more detailed explanation of these compatibility codes can be found in IEEE Standard 488 1978 and the identical ANSI Standard MC1 1 For more information about HP IB refer to the Hewlett Packard Electronic Instruments and Systems catalog and the booklet titled Improving Measurements in Engineering and Manufacturing HP part number 5952 0058 3 25 Remote Mode Remote Capability The Signal Generator com municates on the bus in both remote and local modes In remote most of the Signal Generator s front panel controls are disabled Exceptions are the LINE switch the LOCAL key the MTR keys the MESSAGE key and the FREQUENCY FREQ INCR SWEEP FREQ and SWEEP RATE keys for displaying hidden parameters However front panel displays remain active and valid In remote the Signal Generator can be addressed to talk or listen When addressed to listen the Signal Generator automatically stops talking and responds to the following messages Data Trigger if configured Clear SDC Remote Local Local Lockout and Abort When ad
130. data and the units terminator The frequency may be programmed in units of GHz MHz kHz or Hz To program the Signal Generator to 11232 334 MHz the possible program strings are CF11 232334G2 or CF11232 334MZ or CF11232334KZ or CF11232334000HZ The alpha characters can be sent as upper or lower case or even mixed upper and lower case Program Applicable Code Units GZ Center Frequency Preferred Program Code Operation HP 8673H Detailed Operating Instructions Comments Programming Example 3 56 Center Frequency Sweep conta Due to the use of frequency multiplication to generate frequencies above 6 6 GHz the frequency sometimes cannot be set precisely to a desired value Frequencies below 6 6 GHz can be set to the nearest kHz All frequencies between 6 6 and 12 3 GHz can be set within 2 kHz of the desired value Frequencies between 12 3 and 18 0 GHz can be set within 3 kHz of the desired value However with careful selection of frequency the roundoff error can be reduced to 1 kHz When the Signal Generator is programmed to a frequency that cannot be set exactly due to frequency resolution a random roundoff occurs To prevent this the remote program should perform a calculation to determine whether the frequency can be set exactly and adjust the desired frequency accordingly To determine whether a frequency can be set to a given value divide the desired frequency in kHz by two if it is between 6
131. ddress or a bus command if the bus is in the command mode The command mode is defined as attention control line ATN true and interface clear control line IFC false Whenever the Signal Generator is addressed if in local or remote either the TLK or LSN annunciator on the front panel turns on The Signal Generator s Talk and Listen addresse can be set from switches located inside the instrument or from the front panel The address selection procedure is described in Section 2 The decimal equivalent of the addresses can be displayed in the FREQUENCY MHz display by pressing and holding the LOCAL key This is the decimal equivalent of the last five bits of both the Talk and Listen ASCII address codes Refer to Table 2 1 for a comprehensive listing of all valid HP IB address codes Listen Only Mode If the internal Listen Only switch is set to 1 the Signal Generator is placed in the Listen Only mode The instrument then responds to all Data messages and the Trigger Clear and Local Lockout messages It can also respond to a parallel poll with the Status Bit message However the Signal Generator cannot send Data messages and cannot respond to a serial poll with the Status Byte message The Signal Generator s Listen Only address can also be set from the front panel by keying in 4 0 then pressing the STO key and the LOCAL key Note that the FRONT PNL ENABLE switch on the internal HP IB address switch must be set to 1 to allow fr
132. dressed to talk the Signal Generator automatically stops listening and sends one of the following messages Data Require Service or Status Byte Whether addressed or not the Signal Generator responds to the Clear DCL Local Lockout Clear Lockout Set Local and Abort messages In addition the Signal Generator can issue the Require Service message and the Status Bit message Local to Remote Mode Changes The Signal Generator switches to remote operation upon receipt of the Remote message The Remote message has two parts They are Operation SPB a Remote enable bus control line REN set true b Device listen address received once while REN is true When the Signal Generator switches to remote the RMT annunciator on the front panel turns on With the exception of VERNIER which may change by less than 0 1 dB the Signal Generator s control settings remain unchanged with the Local to Remote transition 3 26 Local Mode Local Capability In local the Signal Generator s front panel controls are fully operational and the instrument responds to the Remote message The Signal Generator can send a Require Service message a Status Byte message and a Status Bit message Remote to Local Mode Changes The Signal Generator switches to local from remote whenever it receives the Local message GTL when addressed to listen or the Clear Lockout Set Local message The Clear Lockout Set Local message sets the Remote Enable con
133. dwell time The number of steps can be set in either of two ways STEP To set the number of steps to be used in a sweep press O use the numeric keys to enter the number of steps then press The sweep span is divided by the number of steps to determine the step size STEP To set the step size press use the numeric keys to enter the step size then press Ce The sweep span is divided by the step size to determine the number of steps The dwell time determines how much time elapses before the next frequency step is taken DWELL To set the dwell time press Q use the numeric keys to enter time in milliseconds then press SWEEP MODE To start a sweep press AUTO for a repetitive sweep The Auto key indicator will remain lit to indicate sweep has stopped MANUAL for a sweep that is controlled by the TUNE knob or the FREQ INCREMENT Up or Down keys SINGLE ec for one sweep only Press this key once to tune the Signal Generator to the start frequency Then press this key again to actually initiate the sweep OFF To stop a sweep in any mode press HP 8673H 3 9 GENERAL INSTRUCTIONS Before the instrument is switched on all protective earth terminals extension cords auto transformers and devices connected to it should be connected to a protective earth grounded socket Any interruption of the protective earth grounding will cause a potential shock hazard that could result in personal injury Only 250V normal
134. e a INTERNAL b DIODE c PWR MTR Power Meter d SYS System INTERNAL RF power output from the signal generator is automatically leveled DIODE RF output power is leveled externally using a diode detector connected to the instrument s EXT ALC IN connector PWR MTR Power Meter RF output power is leveled externally using a power meter connected to the instrament EXT ALC IN connector SYS System RF output power is leveled externally using a feedback voltage proportional to the system output power in volts per dB A system is the Signal Generator with an external amplifier multiplier etc The reference voltage must be 0 Vdc at 0 dBm system output and change 30 mV per dB This voltage is connected to the Signal Generators EXT ALC IN connector HP 8673H ALC Automatic Level Control cont d CAL Adjustments Power leveled at the load is adjusted to agree with the OUTPUT LEVEL meter reading when external leveling is used in DIODE or PWR MTR External leveling techniques are discussed in Hewlett Packard Application Note 281 5 Microwave Synthesizer Series May 1981 HP Part Number 5952 8251 Application Note 218 5 specifically applies to the HP 8672A however the main principles of applications also apply to the HP 8673H Additionally the input voltage fed back to the HP 8673H EXT ALC IN connector should be within a 1V to 1V range Polarity is of no consequence because an internal circuit in the HP 8673H perfor
135. e 20 OUTPUT 719 USING 2A MG Read message from 8673 30 ENTER 719 USING 2A Message l to clear any old messages 40 SELECT Mode 50 CASE AUTO AUTOMATIC 60 Code W2 Auto sweep mode 70 CASE MANUAL 80 Code W3 90 CASE SINGLE ONCE 100 Code W 6 Arm and begin single 110 CASE ELSE 120 DISP WARNING Invalid sweep mode specified 130 Err _i 140 SUBEXIT 150 END SELECT ber Oo 170 OUTPUT 719 USING 2A Code 180 190 SUBEND End of subroutine Error The following message numbers may be displayed when activating manual sweep mode Each Messages message is explained as it pertains to activating manual sweep mode For a more complete description of the messages see the MESSAGES detailed operating instructions 10 The start and stop frequency are set to the same value No sweep will be generated 11 The current sweep span is set such that the start frequency would be below the frequency range of the instrument The sweep will begin at the lowest sweep point that is within the range of the Signal Generator All sweep points will be allotted but the frequency will not change until the sweep is within the frequency range of the Signal Generator 12 The current sweep span is set such that the stop frequency would be above the frequency range of the instrument The sweep will end at the highest sweep point that is within the frequency range of the Signal Generator All sweep points will be allotted but th
136. e Abort Message The Abort message is the means by which the controller sets the Interface Clear IFC bus control line true When the Abort message is received the Signal Generator becomes unaddressed and stops talking or listening i Table 3 6 HP IB Program Codes 1 of 2 Level RANGE and VERNIER AM OFF AM OFF AM 30 AM 100 Backspace Center Frequency Clear Status Configure Trigger CW Frequency ALC INTERNAL ALC DIODE ALC PWR MIR ALC SYS Mode or SHC2 dB 3 42 Program Parameter Code AF dB FREQ INCREMENT Down DWELL FM DEVIATION OFF FM DEVIATION OFF FM DEVIATION 03 MHz FM DEVIATION 1 MHz FM DEVIATION 3 MHz FM DEVIATION 1 MHz FM DEVIATION 3 MHz FM DEVIATION 10 MHz START Sweep Frequency STOP Sweep Frequency FREQ INCR HP 8673H Operation lt gt Table 3 6 HP IB Program Codes 2 of 2 Program Parameter Program Parameter Code Code FREQ INCR OFFSET or SHFB OFFSET or SHDF FREQUENCY AF OFFSET OFFSET FREQ INCR GHz Hz Increment Frequency Sweep Instrument Preset kHz AUTO PEAK OFF AUTO PEAK ON AUTO PEAK without extra settling time Level RANGE and VERNIER Front Panel Learn Mode Special Function Leam Mode MESSAGE milliseconds MULT or SHFA MULT MHz Marker s OFF Marker 1 Marker 2 Marker 3 Marker 4 Marker 5 TUNE Knob OFF TUNE Knob ON Output Active Parameter Output Couple Out
137. e Signal Generator provides frequency modulation at modulation indexes up to 5 for Locai Procedure Remote Procedure Example frequencies below 6 6 GHz 10 for frequencies between 6 6 and 12 3 GHz and 15 for frequencies between 12 3 and 18 0 GHz The FM modulation index is the peak deviation divided by the modulating rate FM peak deviation is linearly controlled by the signal at the FM IN connector with 1 volt peak developing the maximum deviation for the selected range There are six FM peak deviation ranges available with maximum deviations of 0 03 0 1 0 3 1 3 and 10 MHz respectively FM peak deviation is monitored using the Signal Generator s front panel meter in the FM meter mode The meter monitors the signal at the FM IN connector and displays the corresponding FM peak deviation in MHz An overmodulation condition is indicated by the FM OVERMOD annunciator when the modulation index exceeds 5 or the input signal exceeds 1 volt peak To set the Signal Generator to a desired FM peak deviation 1 Select an FM deviation range that is greater than the desired FM peak deviation 2 Connect an external oscillator to the FM input and set the frequency of the external oscillator to the desired modulation rate at an amplitude of 0 volts 3 Press the Signal Generator s FM meter mode key which is located near the front panel meter This will allow the amplitude of the external oscillator to be monitored as the desired FM peak deviation
138. e controller to read the local VERNIER setting by briefly switching to remote to read the VERNIER setting and then returning the Signal Generator to local mode The VERNIER setting is read by sending the program codes VEOA and then reading the setting The Signal Generator will send the VERNIER setting in fundamental dBm units If the VERNIER setting is read as a string the format will be the program code VE followed by the VERNIER setting in dBm and then the units terminator DM dBm The RF output level is read directly by sending the program codes LEOA and then reading the RF output level The Signal Generator will send the RF output level in fundamental dBm units If the RF output level is read as a string the format will be the program code LE followed by the RF output level in dBm and then the units terminator DM dBm The program codes AP or PL can also be used in place of LE but the Signal Generator will always send the program code LE when the RF output level is read as a string To set the RF output level to 56 dBm Local 1 Press the ALC INT key to place the Signal Generator into internal ALC mode The process for setting the RF output level for external ALC modes is covered under the appropriate ALC mode 2 Set the RANGE to the lowest range that is less than 10 dB above the power or 50 dBm in this case 3 Adjust the VERNIER until the level meter indicates 6 dBm For the 50 dBm RANGE the VERNIER can adjust the output
139. e frequency range of the instrument The sweep will begin at the lowest sweep point that is within the range of the Signal Generator All sweep points will be allotted but the frequency will not change until the sweep is within the frequency range of the Signal Generator 12 The current sweep span is set such that the stop frequency would be above the frequency range of the instrument The sweep will end at the highest sweep point that is within the frequency range of the Signal Generator All sweep points will be allotted but the last sweep points will all be at the highest valid frequency 90 Auto Peak malfunction This indicates that the instrument may require service 3 53 Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 54 Center Frequency Sweep The sweep center frequency is used in conjunction with the sweep delta frequency to set the frequency sweep limits The sweep frequency limits can also be set using the sweep start and stop frequencies Setting the sweep start and stop frequency will begin the sweep at the start frequency and end the sweep at the stop frequency Setting the center frequency and delta frequency will start the sweep at one half the sweep delta frequency below the center frequency and end the sweep at one half the sweep delta frequency above the center frequency Setting the CW frequency when sweep modes are off will also reset the sweep center frequency to the same v
140. e front panel VERNIER is as fine as can be measured While the r solution of the remote mode DAC is 0 1 dB Optimum AM performance is achieved for VERNIER settings of 0 dBm and below Highest harmonic levels occur at high VERNIER settings while subharmonics and spurious signals are highest at low VERNIER settings Changing ranges below 0 dB will result in approximately the same performance as the 0 dB range at the lower RF output level The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program will set the output level between 100 and 13 dBm If a level above 0 dBm is set and the Signal Generator is not leveled an error will be reported 10 SUB Rf_level Err Expected Expected is in dBm 20 i 30 If Expected lt 100 OR Expected gt 13 THEN 40 Err 1 50 DISP ERROR Requested output level is out of range 60 SUBEXIT 70 ENDIF so 90 OUTPUT 719 USING 2A MG Clear old messages 100 ENTER 719 USING 2A Message 110 120 OUTPUT 719 USING 4A 4D D 2A CSLE Expected DM Set the level 130 140 OUTPUT 719 USING 4A LEOA 150 ENTER 719 USING K Level 160 3 170 IF ABS Level Expected gt 1 THEN More than 1 dB in error 180 Err 1 190 DISP WARNING Programmed level is more than 1 dB in error 200 END IF 220 V SPOLL 719 Get the status byte 230 IF NOT BIT V 3 THEN GOTO 220 Wait for source to settle 3 153 vperauon HP 8673H Detailed Operating Instructions Ve
141. e if Auto Peak is to remain disabled K1 is used to enable Auto Peak operations if Auto Peak is disabled when the program code is received If Auto Peak is enabled when the program code is received an Auto Peak operation is performed and Auto Peak is left enabled In either case this program code will perform an Auto Peak operation Part of the Auto Peak operation algorithm involves a delay for frequency changes of more than 1 GHz or band crossings This delay is required to eliminate the effects of filter drift after a large frequency change The filter is immediately tuned to the correct frequency when the frequency change occurs and then the algorithm waits for the filter to settle In applications that require a very fast measurement cycle the Auto Peak may be performed immediately after the frequency change by sending the program code K2 after the frequency change This will immediately perform an Auto Peak operation but will not correct for the filter drift as the filter settles Some experimentation may be required to determine whether a measurement system can benefit from the faster Auto Peak operation The SOURCE SETTLED bit of the extended status byte will be set to indicate that the Auto Peak operation has been completed Since the settling times of other operations are also indicated by the setting of this bit the status byte should be cleared before performing the Auto Peak operation The Auto Peak can then be performed and will be fi
142. e indicates whether a change has occurred in the Extended Status Byte If Bit 3 is true the second status byte should be accessed via the Output Status function to determine the cause of the status change The bit pattern can be interpreted with the information in Figure 3 11 3 43 Clearing the Status Byte Once the Signal Generator sets the SRQ bus line true it is no longer allowed to alter the Status Byte If a bit has been enabled and the condition occurs after the SRQ bus line has been set true the bit is stored in a buffer and is read the next time the Signal Generator receives the Serial Poll Enable SPE bus command When addressed to talk following SPE the Signal Generator sends the Status Byte message After the Status Byte message has been sent it will be cleared if the Serial Poll Disable SPD bus command is received if the Abort message is received or if the Signal Generator is unaddressed to talk However bits stored in the buffer waiting to be read are not cleared Regardless of whether or not the Status Byte message has been sent the Status Byte and any Require Service message pending will be cleared if a Clear Status CS program code is received or the Output Status function is executed NOTE The Signal Generator must receive a universal untalk command after sending the Status Byte message Most system controllers send this automatically However if a universal untalk command is not sent the SRQ bus line ma
143. e last sweep points will all be at the highest valid frequency 90 Auto Peak malfunction This indicates that the instrament may require service 3 89 Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 90 Marker Frequency Sweep The Signal Generator has five markers that can be used during a sweep to activate rear panel control signals when selected frequencies are generated These control signals can be used to generate distinctive calibrated frequency markers on an external display Using the Signal Generator s markers provides up to five easily identified display markers at known frequencies When a marker is activated an extra frequency point at the sweep marker frequency will be generated during a sweep and the BLANKING MARKER and TONE MKR signals will be activated The rear panel BLANKING MARKER signal is used to produce a 5 volt dc level to intensify a portion of the trace on a CRT display Z axis input The signal level will be zero volts de for non marker frequencies The TONE MKR is a 5 kHz signal that can be used to amplitude modulate the RF output signal of the Signal Generator or can be summed into an external display to generate a distinctive marker on the displayed trace Each of the five markers can be set to trigger on any valid Signal Generator frequency and can be individually enabled or disabled Each active marker will add a distinct frequency to the sweep even if two m
144. e output level The Signal Generator will send the level in units of dBm 102 to 13 0 If the RF level is read as a string the format will be the program code LE followed by the RF output level in dBm and then the units code DM The program code AP or PL can be used instead of LE but the program code returned from the Signal Generator will always be LE 3 83 Operation HP 8673H Detailed Operating Instructions Example Program Codes Comments Internal Automatic Level Control cont d To set the Signal Generator to an output level of 16 dBm Local 1 Press the ALC INT key on the Signal Generator to set the leveling to internal 2 Set the Signal Generator RANGE to 10 dB The VERNIER can be adjusted for levels between 20 and 7 dBm in the 10 dB range 3 Adjust the VERNIER for a 6 dBm reading on the LEVEL meter This sets the output level to 16 dBm Remote The program string to set the ALC mode and the output level is C1LE 16DM Additional information on setting the output level can be found under RANGE and VERNIER detailed Operating instructions Program Description Code Internal Automatic Leveling Control Internal ALC is used to control the intemal RF signal over a range of 10 to 13 dBm Additional dynamic range is provided by a 90 dB step attenuator to give an effective dynamic range of 100 dBm to 13 dBm The actual maximum leveled power available is dependent on the frequency and varies for the d
145. e output is valid and the program may continue If the frequency is programmed and the status byte is not checked the program should wait at least the frequency switching speed time before assuming the output valid If the status byte is to be used to monitor settling the program string that sets the frequency should start with the program code CS This will clear any previous setting of the SOURCE SETTLED bit to avoid an incorrect indication The following programs are written in BASIC for HP 9000 Series 200 or 300 controllers The program below is used to set the Signal Generator to the sweep start frequency specified by the variable called Expected The desired value must be in MHz and should be within the frequency range of the Signal Generator 10 SUB Sweep_start_set Err Expected Expected frequency in MHz 20 OUTPUT 719 USING 2A MG Read message from 8673 30 ENTER 719 USING 2A Message to clear any old messages 40 Frequency INT Expected 1000 1000 Round off to nearest kHz 50 OUTPUT 719 USING 4A 5D DDD 2A CSFA Frequency MZ Update status 60 CALL Settled Wait for source to settle 3 127 Operation HP 8673H Detailed Operating Instructions Start Frequency Sweep cont d Programming 70 OUTPUT 719 USING 2A MG Check for message from 8673 Example 80 ENTER 719 USING 2A Message cont d 90 SELECT VAL Message 100 CASE 1 Frequency was out of range 110 Err i 120 DISP WARNING Attempt to set sweep start freque
146. e rear of the top cover and loosening the screw at the middle of the rear edge of the top cover c Remove the A2A2 Key Code board by gently lifting the board s extractors the extractors are color keyed red and black d The jumper is located on the center of the board e To enable the debounce circuit remove the jumper from W2 and reinstall the jumper at W1 f Reinstall the A2A2 Key Code board and the Signal Generator s top cover Figure 2 5 AUX Interface Connector i f HP 8673H Operation SECTION 3 OPERATION 3 1 INTRODUCTION This section provides complete operating information for the HP 8673H Signal Generator Included are both general and detailed operating instructions detailed descriptions of the front and rear panel local and remote operator s checks and operator s maintenance procedures 3 2 System Compatibility System compatibility is defined as the ability of the Signal Generator to operate in system mode System mode enables the Signal Generator to control a compatible external amplifier frequency multiplier etc 3 3 Operating Characteristics Table 3 1 briefly summarizes the major operating characteristics of the Signal Generator This table is not intended to be a complete listing of all operations and ranges but gives a general description of the instrument s capabilities For more information on the Signal Generator s capabilities refer to Table 1 1 Specifications and Table 1 2 Sup
147. ed after the sweep step size has been entered using the numeric keypad Remote The programming string for setting the sweep start frequency is composed of a program code numeric data and the units terminator The frequency may be programmed in units of GHz MHz kHz or Hz To program the sweep step size to 455 kHz the possible program strings are SP 000455GZ or SP 455MZ or SP455KZ or SP455000HZ In addition the program code SS can be used in place of SP in the above program strings The alpha characters can be sent as upper or lower case or even mixed upper and lower case Program Applicable Code Units GZ SP Sweep step size MZ SS KZ Preferred Program Code The Signal Generator digital sweep is composed of discrete frequencies that are produced sequentially The minimum step size is limited to the minimum change in frequency that the Signal Generator can produce which is defined as the frequency resolution The sweep step size can change depending on the current frequency and the next frequency in the sweep 3 141 Operation HP 8673H Detailed Operating Instructions Comments cont d Programming Example Error Messages 3 142 Step Size Sweep cont d The actual change in output frequency will not be uniform for some frequencies and may vary up to 2 kHz This is required to accommodate sweep step sizes that are not exact multiples of the frequency resolution The sweep steps averaged ov
148. ed to listen the Signal Generator executes a pre viously selected program code It responds equally to the Group Execute Trigger GET bus command and program code TR a Data message Sets output to 9000 000 MHz at 70 dBm with sweep and modulation off Resets many additional parameters as shown in Table 3 5 Responds equally to Device Clear DCL and Selected Device Clear SDC bus commands 5 Remote mode is enabled when the REN bus control line is true However remote mode is not entered until the first time the Signal Generator is addressed to listen The front panel RMT annunciator lights when the instrument is actually in the remote mode RLI The Signal Generator returns to local mode front panel control It responds equally to the Go To Local GTL bus command and the front panel LOCAL key The Signal Generator returns to local front panel control and local lockout is cleared when the REN bus control line goes false Pass Con trol Take Control The Signal Generator has no controller capability Require Service The Signal Generator sets the SRQ bus control line true if one of the fol lowing conditions exists and it has been enabled by the Request Mask to send the message for that condition Front Panel Key Pressed Front Panel Entry Complete Change in Extended Status Source Settled End of Sweep Entry Error and Change in Sweep Parameters
149. ed until a valid sweep step size is obtained The number of steps must be between 1 and 9999 steps If the sweep step size is adjusted the entered value of number of steps is retained for use when other sweep parameters are changed This feature enables the sweep parameters to be entered in any order without restrictions due to previous sweep parameters that do not affect the final values For example if the number of steps is entered as 200 with the current sweep span defined as 100 kHz the number of steps will be adjusted to be 100 1 kHz resolution and a message will be issued However changing the sweep span to 200 kHz will restore the number of steps to 200 without having to re enter the value The Signal Generator accepts any number of s weep steps between 1 and 9999 steps The programmed value may be adjusted as required to be consistent with the remaining sweep parameters and the frequency resolution The format of the remote programming follows the front panel key sequence The program code SS or SP is sent followed by the desired number of steps and the units SS 3 137 Operation HP 8673H Detailed Operating Instructions Remote Procedure cont d Example Program Codes Comments 3 138 Steps Sweep conta The programmed number of Steps can be read by the controller using the output active program code suffix To read the current number of steps the program string SPOA or SSOA is sent and then the step size an
150. eep modes The sweep frequency limits are determined by setting either the start and stop frequency or the center frequency and frequency span Setting start and stop frequency will begin the sweep at the start frequency and end at the stop frequency Setting the center frequency and frequency span will start the sweep at one half the frequency span below the center frequency and end the sweep at one half the frequency span above the center frequency Setting the CW frequency when sweep is off will also reset the sweep center frequency to the same value Setting the center frequency or frequency span will automatically recalculate the appropriate sweep start and stop frequencies Resetting the sweep start or stop frequency will reset the sweep center frequency if in sweep mode or the CW frequency if sweep is off The frequency span will be recalculated whether sweep is on or off The sweep center frequency or CW frequency will be reset to be halfway between the start and stop frequencies The sweep stop frequency can be set to any valid Signal Generator frequency In addition if the start frequency is set above the stop frequency single and auto sweep modes will still sweep from the start to the stop frequency Manual sweep will start at the lower absolute frequency and move toward the higher absolute frequency To set the Signal Generator to a specific sweep stop frequency 1 Press the SWEEP FREQ STOP key to indicate that the next entry will be f
151. ely If the single sweep mode is armed when a W4 program code is received the sweep will execute Program f Description Coda W4 Single Sweep Arm or Execute w5 Single Sweep Arm Only W6 Single Sweep Arm and Execute HP 8673H Comments Operation Detailed Operating Instructions Single Sweep Mode conta The Signal Generator digital sweep is composed of discrete frequencies that are produced sequentially The minimum step size is limited to the minimum change in frequency that the Signal Generator can produce which is defined as the frequency resolution The number of steps is dependent on the frequency resolution and the frequency span For information regarding sweep time see the DWELL TIME detailed operating instruction The actual change in output frequency during a sweep will not be uniform for some frequency bands and may vary up to 2 kHz This is required to accommodate sweep step sizes that are not exact multiples of the frequency resolution The sweep steps averaged over several sweep points will be equal to the selected sweep step size An example of the averaging is defining a sweep step size of 7 kHz at a start frequency of 11 GHz The minimum tuning increment at 11 GHz is 2 kHz which means that the sweep step size can be 6 kHz or 8 kHz for exact step sizes To obtain a sweep step size of 7 kHz the Signal Generator will step by 8 kHz then 6 kHz and then will repeat the sequence The average step size is 7 k
152. ency response of the automatic level control ALC circuitry Using internal leveling will provide the specified AM bandwidth up to the maximum specified AM depth External leveling will typically preserve the AM bandwidth but is dependent on the detector used System leveling on system compatible Signal Generators will typically reduce the usable AM bandwidth to 80 kHz Useable AM bandwidth can be more than doubled by activating any sweep mode Pulse modulation uses a sample and hold system to maintain pulse level accuracy A capacitor is used to hold the automatic level control ALC circuit setting between pulses When pulse and amplitude modulation are used together the sampling capacitor has the effect of reducing the effective AM bandwidth The effective AM bandwidth when pulse mode and AM are enabled and sweep is disabled is calculated as follows Bandwidth 4 kHz Pw PRF Where Pw is the pulse width in seconds PRF is the pulse repetition frequency in Hz For example a pulse width of 10 microseconds at a pulse repetition rate of 10 kHz will yield an effective AM bandwidth of 400 Hz The effective AM bandwidth is directly proportional to the duty cycle Pw PRF HP 8673H Programming Example Error Messages Operation Detailed Operating Instructions Amplitude Modulation conta The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program will set the AM range to an appropriate setting a
153. ended status byte changes This is useful in applications requiring retuning of test instruments under remote control while allowing an operator to manually tune the Signal Generator Serial Poll When a condition occurs that sets one of the bits of the status byte or the extended status byte the bit is set and remains set until it is cleared by the controller When the status byte is cleared all bits are first cleared and then updated to reflect the current status of the Signal Generator HP 8673H Remote Procedure cont d Operation Detailed Operating Instructions Status Byte and Polling conta A serial poll is used to read the status byte without clearing any of the bits of the s tatus byte To read the status byte the command SPOLL is used The status byte is then read intot he controller The status byte is read as the sum of the weighted values of the bits See the status byte in the Comments section to determine bit weight value To clear the status byte the program code CS must be sent or the status byte and extended status byte must be read The clear status command CS will clear both the status byte and the extended status byte If clearing the status changes the extended status byte the CHANGE IN EXTENDED STATUS bit will be set in the status byte This enables the controller to monitor the status byte using a serial poll until the extended status byte changes Reading both status bytes after the output status command OS w
154. equency MZ 60 OUTPUT 719 USING 2A PMG Check for message from 8673 70 ENTER 719 USING 2A Message 80 SELECT VAL Message 90 CASE1 Frequency was out of range 100 Err 1 110 DISP WARNING Attempt to set frequency out of range 120 CASE ELSE 130 Err 0 Other errors not applicable 140 END SELECT 150 160 OUTPUT 719 USING 4A CFOA Requests center frequency 170 ENTER 719 USING K Set_freq Frequency in Hz 180 Set_freq INT Set_freq 1000 1000 Convert to MHz 190 200 IF ABS Set_freq_Frequency gt 001 AND Err 0 THEN 210 DISP WARNING Programmed frequency is incorrect 220 ENDIF 230 SUBEND I End of subroutine HP 8673H Operation Detailed Operating Instructions Center Frequency Sweep cont d Error The following message numbers may be displayed when setting the sweep center frequency Messages Each message is explained as it pertains to setting sweep center frequency For a more complete description of the messages see the MESSAGES detailed operating instruction 01 Entered frequency is not within the range of the Signal Generator 03 Invalid multiplier entry for system compatible instruments See paragraph 3 2 System Compatibility for more information about system compatibility 3 57 Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 58 Delta Frequency Sweep The sweep delta frequency determines the sweep span about the center frequency
155. equency increment 1 Press the FREQ INCR key to indicate that the next entry will be for frequency increment 2 Enter the desired frequency increment using the numeric keypad If a mistake is made while entering the frequency increment press the backspace key until the incorrect digit disappears Continue entering the correct digits until the frequency increment displayed in the FREQUENCY MHz display is correct 3 Press the appropriate units key You may enter the frequency increment in GHz MHz or kHz The entered frequency increment will be displayed as long as the units key is held down The frequency may now be incremented or decremented using the TUNE knob or the FREQ INCREMENT up and down keys The tuning step will be equal to the frequency increment or the tuning resolution whichever is greater For frequency increments that are not a multiple of the frequency resolution the tuning occurs in a way to make the average tuning increment equal to the frequency increment See the comments section for more information about frequency increments that are not a multiple of the frequency resolution HP 8673H Local Procedure cont d Remote Procedure Example Operation Detailed Operating Instructions Frequency Increment and Tuning conta If a sweep mode is active when the frequency increment is entered the frequency displayed after releasing the units key will be either the current RF output frequency or the start and stop
156. equency range Above 6 6 GHz the programmed frequency may be rounded by the Signal Generator to be compatible with the 2 or 3 kHz resolution at the programmed frequency see Comments The format of the remote programming follows the front panel key sequence To program the sweep start frequency the program code FA is sent followed by the desired frequency and the units GZ MZ KZ or HZ If setting the new start frequency causes a change of the CW frequency normally the case the SOURCE SETTLED bit of the status byte can be monitored to determine when the new frequency has settled Once this bit is set the NOT PHASE LOCKED bit in the extended status byte may be checked to ensure that the instrument is working correctly The NOT PHASE LOCKED bit is not valid until after the SOURCE SETTLED bit has been set The current sweep start frequency can be read by the controller using the output active program code suffix To read the start frequency send the program codes FAOA and then read the start frequency The Signal Generator will send the frequency in fundamental Hz units If the frequency is read as a string the format will be the program code FA followed by the sweep start frequency in Hz and then the units terminator Hz To set the sweep start frequency to 11 232 334 MHz Local 1 Press the SWEEP FREQ START key 2 Key in 11232 334 using the numeric keypad The FREQUENCY MHz display should show 11232 334 when you have finished
157. er case HP 8673H Program Codes Comments Programming Example Error Messages Operation Detailed Operating Instructions Dwell Time Sweep cont d Program Applicable ae ETN Sweep DwellTime Dwell Time The Signal Generator digital sweep is composed of discrete frequencies that are produced sequentially The time spent at each of the sweep steps is controlled by the dwell time The actual time between frequencies is dependent on step size band crossings modulation used and whether Auto Peak is enabled With Auto Peak enabled an Auto Peak operation will be performed for every 50 MHz change in frequency from the last frequency where an Auto Peak operation was performed For sweep step sizes greater than 50 MHz an Auto Peak operation will be performed for each sweep step Depending on the adjustment of the instrument the Auto Peak operation can add 30 to 100 milliseconds per step Generally small step sizes over a narrow span will provide the shortest time between steps Dwell times less than 5 milliseconds will not produce a true phase locked signal for all sweeps An algorithm is used to provide the shortest phase lock without waiting for complete settling The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program is used to set the sweep dwell time to the number specified by the variable Expected The desired value must be between 1 and 255 milliseconds 10 SUB Sweep_dwe
158. er is lower From 6 6 to 12 3 GHz peak deviation is limited to the lesser of 10 MHz or ten times the modulation frequency from 12 3 to 18 0 GHz the lesser of 10 MHz or fifteen times the modulation frequency DESCRIPTION cont d Usable modulation rates fall between 100 Hz and 10 MHz Pulse modulation has two operating modes NORM normal mode and COMPL complement mode In normal mode the RF output is On when the drive signal is the TTL high state In the complement mode the RF output is On when the drive signal is in the TTL low state The Signal Generator is compatible with HP IB to the extent indicated by the following code SH1 AH1 T5 TEO L3 LEO SR1 RL1 PP1 DC1 DT1 and CO The Signal Generator interfaces with the bus via three state TTL circuitry An explanation of the compatibility code can be found in IEEE Standard 488 1978 IEEE Standard Digital Interface for Programmable Instrumentation or the identical ANSI Standard MC1 1 For more detailed information relating to programmable control of the Signal Generator refer to Remote Operation Hewlett Packard Interface Bus in Section 3 of this manual 1 6 OPTIONS 1 7 Electrical Options Option 001 The internal 10 dB step attenuator has been deleted The specified output level is listed in Table 1 1 Option 003 A special fan allows operation from 400 Hz power mains as well as 50 60 Hz Option 004 The Signal Generators RF OUTPUT connector is located
159. er several sweep points will be equal to the selected sweep step size An example of the averaging is defining a sweep step size of 7 kHz at a start frequency of 11 GHz The minimum tuning increment at 11 GHz is 2 kHz which means that the sweep step size can be 6 or 8 kHz for exact step sizes To obtain a sweep step size of 7 kHz the Signal Generator will step by 8 kHz then 6 kHz and then will repeat the sequence The average step size is 7 kHz even though the sweep does not execute exactly 7 kHz steps If the step size is reduced to 1 kHz the Signal Generator will step by 2 kHz and then 0 kHz for a 1 kHz average step size When the sweep frequency span is changed the sweep step size is recalculated by dividing the entered span by the current number of steps Entering a sweep step size will recalculate the number of steps by dividing the sweep frequency span by the entered sweep step size The sweep step size will be adjusted until the number of steps is an integer number between 1 and 9999 steps The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program is used to set the Signal Generator sweep step size to the frequency specified by the variable Expected The desired value must be in MHz and should be between 1 kHz and the maximum frequency of the Signal Generator 10 SUB Step_size Err Expected 20 OUTPUT 719 USING 2A MG Clear message from 8673 30 ENTER 719 USING 2A Message i to clear any old mes
160. ered to could result in per sonal injury Do not proceed be yond a WARNING sign until the indicated conditions are fully understood and met The CAUTION sign denotes a hazard It calls attention to an operating procedure practice or the like which ifnot correctly per formed or adhered to could result in damage to or destruction of part or all of the product Do not proceed beyonda CAUTION sign until the indicated conditions are fully understood and met MIVA GE LELIULILIGLIUIE HP 8673H MODEL 8673H TYPE N M ADAPTER H f OPTION 907 FRONT HANDLE KIT OPTION 908 OPTION 909 RACK FLANGE KIT RACK FLANGE AND FRONT HANDLE COMBINATION KIT Figure 1 1 HP 8673H Accessories Supplied and Options 907 908 and 909 1 2 444 OUST OLE VCHCId LINOTHIANON SECTION 1 GENERAL 1 1 INTRODUCTION The HP 8673H Operating Manual contains all the information required to install operate and test the Hewlett Packard Model 8673H Synthesized Signal Generator Figure 1 1 shows an HP 8673H Signal Generator with all of its externally supplied accessories The HP 8673H Operating Manual has four sections Section 1 General Information Section 2 Installation Section 3 Operation Section 4 Performance Tests The HP 8673H Service Manual which is shipped with the instrument as Option 915 or ordered separately has four sections Section 5 Adjustments Section 6 Replaceable Parts Section 7
161. eries 200 or 300 controllers The following program is used to step the Signal Generator from Start to Stop in Step increments A subroutine called Read_power is called after each frequency increment 10 SUB Freq_step Err Start Stop Step Frequencies in MHz 20 CALL Freq_set Err Start Sub under CW Frequency 30 OUTPUT 719 USING 2A 5D DDD 2A F Step MZ 40 IF STOP START lt 0 THEN 50 P_code DN Decrement from Start to Stop 60 ELSE 70 P_code UP 80 ENDIF 90 100 Start Begin the process 110 CALL Read_power Do for this frequency 120 OUTPUT 719 USING 2A P_code Increment or decrement 130 CALL Settled Wait for source to settle 140 OUTPUT 719 USING 2A OK Get new frequency 150 ENTER 719 USING K Frequency This is current frequency 160 IF Frequency lt Stop AND P_code UP THEN GOTO Start Next step 170 IF Frequency gt Stop AND P_code DN THEN GOTO Start 180 190 SUBEND End of subroutine HP 8673H Programming Example cont d Error Messages Operation Detailed Operating Instructions Frequency Increment and Tuning conta Note that the above program does not take into account the different resolution ranges and their effect on the actual step size This is usually n ot significant especially with large frequency increments The following program can be called to wait for a source settled indication from the Signal Generator The program will wait a maximum of 1 second before as
162. es Operation Detailed Operating Instructions Delta Frequency Sweep conta The Signal Generator accepts any sweep delta frequency between 1 kHz andthe maximum Signal Generator frequency Once the sweep delta frequency is entered the Signal Generator will recalculate the sweep start and stop frequencies If the recalculated start and or stop is above 6 6 GHz the calculated frequency may be rounded by the Signal Generator to be compatible with the 2 or 3 kHz resolution at the calculated frequency see comments The format of the remote programming follows the front panel key sequence To program the sweep delta frequency the program code DF is sent followed by the desired frequency and the units GZ MZ KZ or HZ The current sweep delta frequency can be read by the controller using the output active program code suffix To read the stop frequency send the program codes DFOA and then read the delta frequency The Signal Generator will send the frequency in fundamental Hz units If the frequency is read as a string the format will be the program code DF followed by the sweep stop frequency in Hz and then the units terminator Hz To set the sweep delta frequency to 4500 MHz Local 1 Press the SWEEP FREQ AF key 2 Key in 4500 using the numeric keypad The FREQUENCY MHz display should show 4500 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the MHz units key to fin
163. es The Request Mask is cleared by an HP IB clear but not by an instrument preset When a service request is generated whenever the RQS bit is set true the status byte is latched so the first cause of the service request can be identified Reading the stored status byte can only be done using a serial poll Reading the status byte using the output status program code OS will read the current status only Once the stored status byte is read the status byte is updated so a subsequent service request is not lost If more than one bit is enabled to generate a service request and more than one bit is set before the serial poll the first serial poll will read the status byte associated with the first service request Once the poll is completed another service request will be generated due to the one or more other bits that were set after the status byte was stored The service request SRQ HP IB bus line is set true whenever the RQS bit of the status byte is set The front panel SRQ annunciator is also lighted when the RQS bit is set The service request is cleared when a clear status CS is executed or the extended status byte is read OS When the controller detects a service request by testing the HP IB SRQ line a serial poll must be performed for each instrument on the bus to determine which instrument generated the request For large systems the parallel poll can be used to reduce the number of polls required to identify the instrument requiri
164. ess the RCL key to indicate that one of the ten registers is to be recalled The zero register is the preset conditions for the instrument 2 Press one of the numeric keys corresponding to the register that is to be recalled Valid register numbers are 0 through 9 Register 0 the preset register cannot be used to save an instrument state An attempt to store an instrument state in this register will generate an error message If a different set of preset conditions are required one of the nine storage registers may be used to store the alternate preset conditions Pressing RCL and then the backspace key will provide another set of preset conditions see comments The nine storage registers can be used in remote applications If a register is stored in remote mode recalling the register will recall the remote VERNIER setting Local VERNIER control will be locked out until the instrument is preset or the Signal Generator is set to remote mode and then local mode The format of the program string follows the front panel sequence The program code for storing an instrument state is ST Recalling a register is done using the RC program code The program string is composed of the appropriate program code followed by a number corresponding to the appropriate register To store the current instrument settings in register 1 Local 1 Press the blue shift key followed by the RCL key to indicate that the instrument state is about to be saved H
165. essage upon receipt of the 96th character in a string If a block of strings containing more than 96 characters is sent the first 96 characters are accepted and the Signal Generator holds the bus busy until it executes them Then the next 96 characters are accepted and so on until the entire block is accepted If only one string of less than 96 characters is sent the Signal Generator accepts the strings and frees the bus allowing program execution to continue Binary Mode The Signal Generator s Request Mask is programmed in binary format Also learn mode data Operation is sent and received in binary Binary data is always processed in the Immediate Execution mode 3 33 Sending the Data Message The Signal Generator can send Data messages when addressed to talk It remains configured to talk until it is unaddressed to talk by the controller To unaddress the Signal Generator the controller must send the Signal Generator s listen address an Abort message a new talk address or a universal untalk command Talk Functions The types of information that the Signal Generator can send in a Data message are Front Panel Learn Mode Special Function Learn Mode Messages Output Active Parameter Output Couple Output Lock Frequency Test Interface Output Status e Output Request Mask Value explained later under Sending the Request Mask Value e o o o Each function is enabled by first addressing the Signal Generator
166. et precisely to a desired value Frequencies below 6 6 GHz can be set to the nearest 1 kHz All frequencies between 6 6 and 12 3 GHz can be set within 2 kHz of the desired value Frequencies between 12 3 and 18 0 GHz can be set within 3 kHz of the desired value However with careful selection of frequency the roundoff error can be reduced to 1 kHz When the Signal Generator is programmed to a frequency that cannot be set exactly due to frequency resolution a random roundoff occurs To prevent this the remote program should perform a calculation to determine whether the frequency can be set exactly and adjust the desired frequency accordingly To determine whether a frequency can be set to a given value divide the desired frequency in kHz by two if it is between 6 6 and 12 3 GHz or by three if it is between 12 3 and 18 0 GHz If the result is a whole number no remainder the frequency can be set to the desired value For example 12 4 GHz divided by three it is between 12 3 and 18 0 GHz is 4133333 33 kHz Since the dividend is not a whole number this frequency cannot be set exactly The nearest frequencies that can be set are 12 399999 GHz 4 133333X3 and 12 400002 GHz 4 133334X3 Note that the roundoff error is only 1 kHz if 12 399999 GHz is programmed instead of 12 4 GHz For applications that require fastest execution the SOURCE SETTLED bit of the status byte can be used Once the bit is set after a frequency has been programmed th
167. etect when a single sweep is finished so the controller can spend time computing while the Signal Generator is sweeping ENTRY ERROR The ENTRY ERROR bit is set when an invalid front panel key sequence HP IB program code or parameter value is entered This bit corresponds to the front panel MESSAGE key Reading the message after detecting this bit will enable the controller to identify and possibly correct the error RQS SERVICE REQUEST BIT The Signal Generator can generate a service request when one or more of the bits in the status byte are set A request mask must be set to allow one or more of the bits to generate a service request At power on the request mask is set to disable any of the bits from generating a service request A bit is enabled by setting the corresponding bit in the request mask to a logical one true The front panel SRQ indicator will be lighted whenever this bit is set in local or remote mode The HP IB service request will also be generated in remote or local mode CHANGE IN SWEEP PARAMETERS Changing the CW frequency will reset the start and stop frequencies of the sweep Any changes to start or stop frequencies delta frequency number of steps or step size dwell time or center frequency will set this bit Extended Status Byte The extended status byte is read by sending the OS program code to the Signal Generator and then reading the status byte and extended status byte The bits in the extended status byte
168. eter This deviation is not corrected when an external Opera frequency multiplier is used For example if a frequency doubler is being used the actual frequency deviation will be twice that shown on the meter FM iN Connector BNC female connector with an input impedance of 50Q 1 volt peak gives full scale modulation Deviation varies linearly with the input signal level Deviation ranges are controlled by the FM DEVIATION keys purse PULSE OFF Key Disables pulse modulation NORM Normal Mode Key Turns RF output on when the signal to the PULSE IN connector is greater than 2 4 volts COMP Complement Mode Kay Turns RF output on when the signal to the PULSE IN connector is less than 0 4 volts PULSE IN Connector BNC female connector with an input impedance of 502 Accepts TTL levels Figure 3 6 Modulation Features tion 3 15 Operation HP IB Connector Connects the Signal Generator to the Hewlett Packard Interface Bus for remote operation 6 FREQ REF BNC female connector Output impedance is 1009 nominal Provides a 0 5 V GHz voltage that is always on even when sweep is off An internal switch can set the output to 1V GHz 6 SWP OUT BNC female connector Output impedance is 100Q nominal Provides a 0 to 10V ramp from start to stop An internal adjustment can set the slope of the ramp from 0 to between 4 and 12V 6 TONE MKR BNC female connector Output impedance is 600Q nomina
169. evel 24 The programmed RF output VERNIER RANGE or both is outside the Signal Generator s range 3 109 Operation HF 8673H Detailed Operating Instructions Pulse Modulation Description The Signal Generator provides normal and complemented pulse modulation In normal pulse Local Procedure Remote Procedure Example 3 110 modulation a TTL high level gt 3 volts will turn on the carrier while a TTL low level lt 0 5 volts turns the carrier off Complement pulse modulation uses a TTL low level to tum on the carrier and a TTL high level to turn off the carrier Having two modes available allows easiest interfacing to positive or negative logic conventions Pulse widths more narrow than the specified minimum pulse width will light the UNLEVELED annunciator to indicate that the pulse peak level accuracy is degraded Pulse overmodulation is indicated by the UNLEVELED annunciator Pulse overmodulation occurs at narrow pulse widths as mentioned above and at very low duty cycles when the time between pulses exceeds the instrument s ability to retain a leveled pulse To set the Signal Generator for pulse modulation 1 Connect an external pulse source to the PULSE IN connector and set the frequency of the external pulse source to the desired pulse repetition rate Set the amplitude of the external pulse source to a TTL compatible pulse 0 to 5 volts 2 Press the Signal Generator s PULSE NORM key if the TTL high level is to be used
170. eveling control to internal Adjust the Signal Generator output level to place the power meter in the appropriate range to monitor the coupled port over the required range Press the range hold key to prevent a range change A power meter range change will rescale the feedback voltage and cause oscillations in the leveling circuitry 3 Reset the Signal Generator range to at least 10 dB above the range required for the desired RF output level The range may have to be adjusted to compensate for losses and gains in the RF signal path If the RF signal path will have a relatively high loss a higher Signal Generator range will be required 4 Connect the recorder output of the power meter to the external ALC input of the Signal Generator The recorder output signal typically varies from 0 to 2 Vdc for each power meter range corresponding to a 23 dB dynamic range 5 Press the ALC PWR MTR key to set the Signal Generator to external power meter ALC mode 3 105 Operation HP 8673H Detailed Operating Instructions Power Meter Automatic Level Control cont d Local 6 Adjust the ALC CAL control on the Signal Generator front panel until the U NLEVELED Procedure annunciator is extinguished Set the Signal Generator VERNIER for a0 dBm indication on cont d the Signal Generator level meter Continue adjusting the CAL control until the power meter indicates a level that is in the desired leveling range and lower than the VERNIER setting by the couplin
171. f X Y recorders and external displays Manual sweep provides a convenient method to limit the tuning range of the frequency tuning controls In applications requiring a single band of frequencies the tuning limits can be set to cover the band of interest which allows the user to tune the frequency without having to watch the Signal Generator display to determine when the frequency is outside of the selected band There are four rear panel connectors that are used for sweep coordinating signals SWP OUT provides a signal that is 0 volts at the beginning of a sweep and 10 volts at the end of the sweep regardless of the sweep width The output impedance is nominally 100 ohms The TONE MKR connector provides a 5 kHz signal when an active marker frequency is generated This signal can be connected to the AM IN connector on the front panel to provide AM markers on the external display Nominal impedance of the TONE MKR is 600 ohms The BLANKING MARKER output provides a 5 volt signal at the beginning of each frequency change for blanking an external display The blanking function is used to eliminate the display of switching transients Once the frequency has settled the signal returns to 0 volts unless the new frequency is an active marker frequency If the frequency is an active marker frequency the signal is set to 5 volts to provide a Z axis input for intensifying the display at the marker sweep point The PENLIFT connector provides control for an
172. ffset 200 210 IF ABS Offset 1 E 6 Expected gt 001 THEN More than 1 kHz error 220 Err 1 230 DISP WARNING Programmed offset is more than 1 kHz in error 240 ENDIF 250 260 SUBEND The following message may be displayed when setting t he offset frequency The message is explained as it pertains to setting offset frequency For a more complete description of the messages see the MESSAGES detailed operating instructions 01 The entered frequency is not within the range of the Signal Generator HP 8673H Description Local Procedure s Operation Detailed Operating Instructions Power Meter Automatic Level Control External ALC enables the Signal Generator to level the signal at a point other than the output of the Signal Generator The signal level must be detected using a signal splitter or directional coupler with an RF detector or power meter to provide a DC signal that is proportional to power at the remote point The Signal Generator will adjust the signal level at the RF output connector to maintain a constant level at the point where the signal is detected External ALC also enables external devices such as amplifiers mixers and other specialized devices to be inserted into the RF signal path with control of the final output level by the Signal Generator In applications where the external signal path has frequency dependent losses and or gains the RF signal at the end of the signal path will no longer be a cons
173. ffset from carrier gt 6 6 12 3 GHz gt 12 3 18 0 GHz RF OUTPUT Output Level Standard Leveled Output 15 to 35 C 2 0 to 18 0 GHz 8 dBm to 100 dBm Option 001 Leveled Output 10 dBm to 100 dBm 2 0 to 18 0 GHz Option 004 Leveled Output 7 dBm to 100 dBm 2 0 to 18 0 GHz Option 005 Leveled Output 9 dBm to 100 dBm 2 0 to 18 0 GHz Remote Programming Absolute Level Accuracy 2 0 6 6 GHz 15 to 35 C 10 dBm output level range 0 dBm output level range 10 dBm output level range 20 dBm output level range 30 dBm output level range lt 30 dBm output range 1 25 dB 1 00 dB 1 50 dB 1 70 dB 2 00 dB 2 00 dB plus 0 1 dB per 10 dB step below 30 dBm 1 50 dB gt 6 6 12 3 GHz 10 dBm output level range 1 25 dB 0 dBm output level range 1 75 dB 10 dBm output level range 1 95 dB 20 dBm output level range 2 25 dB 30 dBm output level range 2 25 dB plus 0 1 dB per 10 dB step below 30 dBm lt 30 dBm output range General information HP 8673H Table 1 1 Specifications 3 of 6 Electrical Characteristics Performance Limits Conditions RF OUTPUT cont d gt 12 3 18 0 GHz Manual Absolute Level Accuracy Remote Programming Output Level Resolution Flatness Output Level Switching Time to be within 1 dB of final level PULSE MODULATION ON OFF Ratio Rise an
174. fset Frequency Recall and Store Registers Status Byte and Polling MODULATION Amplitude Modulation Frequency Modulation Pulse Modulation RF OUTPUT LEVEL Range Output Level RF Output On Off Vernier Output Levei Auto Sweep Mode Center Frequency Sweep AFrequency Sweep Dwell Time Sweep Manual Sweep Mode Marker Frequency Sweep Single Sweep Mode Start Frequency Sweep Steps Sweep Step Size Sweep Stop Frequency Sweep HP 8673H Description Local Procedure Remote Procedure Example Operation Detailed Operating Instructions Amplitude Modulation The Signal Generator provides linear amplitude modulation when internally leveled or when externally leveled with a power meter External leveling with a diode detector requires that the diode is operating in the square law region to provide linear amplitude modulation The Signal Generator has a selectable sensitivity of 30 AM per volt or 100 AM per volt AM depth is linearly controlled by varying the AM input drive level between 0 and 1 volt peak into 600 ohms For example 0 5 volts peak will develop 15 AM depth on the 30 range and 50 AM depth on the 100 range AM depth is monitored using the Signal Generator s front panel meter in the AM meter mode The meter monitors the signal at the AM input connector and displays the corresponding AM depth in percent An overmodulation condition is indicated by the UNLEVELED annunciator when the modulation depth
175. fset frequency using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue entering the correct digits until the frequency displayed in the FREQUENCY MHz display is correct 4 Press the appropriate units key The frequency may be entered in GHz MHz or kHz Once the units key is pressed the displayed frequency will be adjusted to display MHz and the offset frequency will be displayed until the units key is released Once the units key is released the FREQUENCY MHz display will be adjusted to display the RF output frequency offset by the entered offset frequency When the offset mode is activated the OFFSET front panel annunciator will be lighted to indicate that the actual frequency is not the displayed frequency Entering an offset of zero will deactivate the offset frequency mode An instrument preset will also clear the offset frequency and deactivate offset frequency mode Once the offset frequency is entered all subsequent frequency entries will be adjusted before setting the actual output frequency For a positive offset the actual frequency will be lower then the entered frequency and for a negative offset the actual frequency will be higher than the entered frequency The offset frequency can be programmed to any frequency between 1 kHz and the Signal Generator s maximum frequency Once the offset is programmed frequencies read by the controller
176. fy that the SUNLOCKED annunciator remains off at both frequencies Output Level Check The Signal Generator s internal Automatic Leveling Control ALC is checked to ensure that it remains leveled at all speeitiga power levels The ALC monitors most of the RF output circuitry 12 Press RCL 0 to set the Signal Generator to a known state 13 Connect a6 dB attenuator or 50Q load to the Signal Generator s RF OUTPUT connector This reduces unwanted power reflections back into the RF OUTPUT connector thereby preventing a false UNLEVELED annunciator indication 14 Set FREQUENCY to 6 6 GHz and Output Level VERNIER to 2 dBm 15 Press the RF OUTPUT key to OFF Verify that the UNLEVELED and gUNLOCKED status annunciators turn on and that the meter indicates lt 10 dBm 16 Press the RF OUTPUT ON OFF key to ON Verify that the status annunciators turn off and that the meter indicates 2 dBm 17 Step the output level down in 10 dB steps from 0 to 90 dB using the RANGE key Then step the output level up in 10 dB steps from 90 to 10 dB Verify that the UNLEVELED annunciator remains off at each step 18 Set Output Level RANGE to 0 dB and sweep the Output Level VERNIER from 10 dBm to 3 dBm Verify that the UNLEVELED annunciator remains off at all VERNIER settings 19 Press RCL 0 to set the Signal Generator to a known state 20 Set frequency to 12 4 GHz Option 212 or 16 1 GHz Option 618 21 Repeat step 18 Operation OPERATO
177. g conta SUB Source_settled Time_in TIMEDATE Reference for timeout Check_it V SPOLL 719 Take a serial poll to check the bit Check for set bit or more than 3 seconds IF NOT BIT V 3 AND TIMEDATE Time_in lt 3 THEN GOTO Check _it SUBEND gt 3 seconds or bit is set The parallel poll is set up using the Request Mask and the parallel poll commands of the controller The following program sets up a parallel poll to check for entry errors or changes in the extended status The parallel poll response will be positive and set for line 1 of the HP IB bus The second subroutine is used to test the HP IB with a parallel poll and call a user subroutine Err_8673 The poll indicates an SRQ by the HP 8673 100 SUB Set_8673_poll 110 Mask 4 32 Bits for Entry error 32 and status change 4 120 PPOLL CONFIGURE 719 148 Line one with positive sense 130 OUTPUT 719 USING 2A B RM Mask Enable bits 140 SUBEND 150 SUB Poll_bus 160 Bus PPOLL 7 170 IF BIT Bus 1 THEN CALL Err 8673 Routine will serial poli 180 SUBEND 180 SUB Err_8673 200 V SPOLL 719 210 IF BIT V 5 THEN l Entry error occurred 220 DISP Entry error occurred for HP 8673 Press MESSAGE key 230 PAUSE 240 OUTPUT 719 MG Clear message to prevent more requests 250 ENTER 719 Dummy 260 DISP i Clear display line 270 ENDIF 280 IF BIT V 2 THEN Change in extended status is indicated 290 OUTPUT 719 0S 300 ENTER 719 USING B B Statt Stat2
178. g the instrument for 220 240 Vac operation c One adapter is provided a TYPE N M to SMA F 50Q coaxial adapter HP Part No 1250 1250 1 11 EQUIPMENT REQUIRED BUT NOT SUPPLIED An external signal source is required if amplitude frequency or pulse modulation is desired For AM the source should have a variable output of 0 to 1V peak into 600Q frequency rates up to 100 kHz For FM the source should have a variable output of O to 1V peak into 509 frequency rates up to 10 MHz and distortion of less than 1 For pulse modulation the source should have TTL output levels gt 2 4V for a TTL high state and lt 0 4V for a TTL low state and 50 ohms nominal impedance Pulse repetition frequency rates should be 50 Hz to 1 MHz with transition times lt 10 ns 1 12 ELECTRICAL EQUIPMENT AVAILABLE The Signal Generator has an HP IB interface and can be used with any HP IB compatible computing controller or computer for automatic systems applications The HP IB Controller and various ROM s are needed to do the automated SRD Bias YTM Tune Flatness and ALC adjustment procedures Specific equipment needed for automated adjustments are General information Test Cassette HP Part No 11726 10002 HP 85F Controller 82903A 16K Memory Module 00085 15005 Advanced Programming ROM 00085 15002 Plotter Printer ROM 00085 15004 Matrix ROM HP 3455A Digital Voltmeter HP 436A HP 8481A Power Meter and Sensor Although the test cassette is p
179. g Instructions Internal Automatic Level Control conta Comments Subharmonics are due to the frequency multiplication process within the Signal Generator cont d Frequencies above 6 6 GHz are generated by multiplying the fundamental 2 to 6 6 GHz microwave signal by two or three to provide output frequencies up to 18 0 GHz In the multiplied bands there is feedthrough from the fundamental and its harmonics These spurious signals are termed subharmonics and are typically at a fixed amplitude with respect to the multiplied frequency For this reason the higher VERNIER settings provide a better signal to spurious ratio Programming The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The Example following program is used to set the ALC mode of the Signal Generator Valid Mode strings are INTERNAL DIODE POWER METER and SYSTEM 10 SUB Set_aic Err Mode 20 IF Mode INTERNAL THEN P_code C1 30 IF Mode DIODE THEN P_code C2 40 IF Mode POWER METER THEN P_code C3 50 IF Mode SYSTEM THEN P_code C4 60 OUTPUT 719 USING 2A P_cade 70 END Error The following message may be displayed when programming the RF output level Messages 24 The programmed RF output level is outside of the Signal Generator s range Operation HP 8673H Detailed Operating Instructions Description Local Procedure Manual Sweep Mode The Signal Generator performs a digital sweep by stepping
180. g factor For example for a desired level in the range of 17 to 10 dBm using a 10 dB directional coupler adjust the CAL control for a power meter reading of 20 dBm A more accurate calibration can be made using another power meter at the output of the directional coupler This will eliminate a possible error due to the coupling factor and will give greater assurance that the output of the coupler is accurate Once the calibration is complete the level at the output of the directional coupler can be varied over a 3 to 10 dB range If turning the CAL control fully clockwise does not have sufficient range to calibrate the output level set the range higher until the calibration can be completed If the output level cannot be set low enough step the RANGE down until the calibration can be performed as described in this step Using the highest range will provide the best compensation for increasing losses higher power levels at the Signal Generator output Using a lower range will provide the best compensation for decreasing losses See the comments section for more information on selecting the optimum range Remote The equipment setup for remote control of power meter leveling is the same as the local Procedure procedure However the calibration must be performed manually The program code for power meter ALC is C3 Once the calibration is complete the level can be remotely controlled by programming the VERNIER to the appropriate level C
181. g the TUNE knob clockwise Verify that the FREQUENCY MHz display changes in 20 MHz increments and stops at 10 000 000 MHz Tune the frequency down to 8000 000 MHz by turning the TUNE knob counterclockwise Verify that the FREQUENCY MHz display changes in 20 MHz steps and stops at 8000 000 MHz Press the SWEEP OFF key and verify that the FREQUENCY MHz returns to 9000 000 MHz Press the SINGLE sweep key Verify that the key indicator turns on and the FREQUENCY display shows 8000 000 MHz Press the SINGLE sweep key again A single sweep should now be executed Verify that the FREQUENCY MHz display changes in 20 MHz steps very rapidly until 10 000 000 MHz is reached The display then returns to the START frequency of 8000 000 MHz Press the SWEEP OFF key Verify that the FREQUENCY MHz display returns to 9000 000 MHz AM Check The front panel meter and UNLEVELED status annunciator are used as an indication of AM The meter monitors input signal level only rather than actual AM A modulation analyzer can be used to monitor the signal at the RF output connector for greater assurance of AM performance 31 Press RCL 0 to preset the Signal Generator to a known state Q673H SYNTHESIZED TEST OSCILLATOR Be aer IH SYNTES IZE OSCILLOSCOPE Figure 3 8 AM Functional Check Setup 3 21 Operation HP 8673H OPERATOR S CHECKS Basic Functional Checks cont d Procedure 32 Set the test oscillator to 10 kHz at a minimum output level
182. ge in Extended Status when one of the bits on the Extended Status Byte changes e Source Settled when the Signal Generator is settled Switching transients occur when RF and AUTO PEAK are turned on and when FM ranges and frequency are changed If the controller responds to the Signal Generator as soon as the source is settled instead of waiting a specified time program speed is increased Entry Error When an invalid keystroke or program command occurs e New Sweep Parameters when the value of START STOP AF DWELL STEP or any Marker changes HP 8673H Sending the Require Service Message cont d The Signal Generator can send a Require Service message in either the local or remote mode The Signal Generator sends a Require Service message by setting the Service Request SRQ bus line true The SRQ annunciator on the front panel turns on when the Require Service message is being sent The Require Service message is cleared after the Output Status function or the Clear Status CS program code has been executed by the controller Request Mask The Request Mask functions within the Status Byte It determines which bits can set the RQS bit true see Figure 3 11 and consequently set the SRQ bus line true The Request Mask is set by the program code 1 followed by an 8 bit byte a Data Message The value of the byte is determined by summing the weight of each bit to be checked Each bit if true enables a correspondi
183. ge register to save current instrument settings in an internal register 6 Data Keys 0 9 and Used with Function keys that is FREQUENCY FREQ Operation INCR and sweep function keys and Units keys to set value selectable parameters Data keys 1 9 are also used with STO and RCL to identify the storage register The backspace key clears one digit at a time starting with the least significant digit It is used only during data entry and before any Units key is pressed units Keys MKR OFF STEPS ms GHz MHz and kHz Used as a suffix to Function and Data keys to set value selectable parameters Frequency entries can terminate in GHz MHz or kHz but they are always displayed in MHz The MKR OFF STEPS ms key serves as a terminator for setting the number of steps in a sweep the dwell time in ms or as a means of turning off markers The selected function automatically determines the applicable terminator The STEPS ms key contains a shifted function XFREQ This function is used as a terminator for the multiplier entry function Entry sequence is SHIFTED START m n STEPS ms The digits m and n represent the multiplier number 1 99 and may be entered as a single digit TUNE ON OFF Key Enables the TUNE knob when ON disables the TUNE knob when OFF The key indicator lights when it is ON Figure 3 4 Frequency Control Features and LINE Switch 1 of 2 Operation fd alc
184. h buffered output capability an additional wait HP 8673H Description cont d BITS BIT 6 BIT7 BIT 8 Operation Detailed Operating Instructions Status Byte and Polling conta is required to allow the buffered output to be received by the Signal Generator However for applications requiring faster execution the source settled bit can be monitored to determine when the RF output has settled Since most frequency changes will be much faster than the worst case frequency switching time the application will execute faster if the SOURCE SETTLED bit is monitored The SOURCE SETTLED bit is intended to indicate settling after the RF output or AUTO PEAK is turned on and when FM ranges frequency output level or pulse modes are changed The bit will be set after any parameter change except AM storing a register and changing sweep parameters that do not immediately change the output frequency However the bit is not always valid as an indication that the RF output is settled and should only be used to check for settling of the intended parameter changes END OF SWEEP During sweep mode the END OF SWEEP bit is used to indicate that the current sweep has finished In AUTO sweep mode the bit will be set once each time the stop frequency is reached In MANUAL sweep mode the bit will be set anytime the start or stop frequency is reached The bit is set when the stop frequency is reached for SINGLE sweep mode The bit can be used to d
185. hanging the range while using external power meter leveling will have no affect on the level but can force the Signal Generator to lose control of the level due to insufficient attenuation lack of ALC dynamic range or too much attenuation attempted operation beyond maximum power specification The VERNIER setting can be read by the controller using the output active program code suffix To read the VERNIER setting send the program string VEOA and then read the VERNIER setting using the ENTER command The Signal Generator will send the VERNIER setting in units of dBm If the setting is read as a String the format will be the program code VE followed by the VERNIER setting in dBm and then the units code DM Example To set the Signal Generator to power meter leveling over the range of 10 to 0 dBm using a 10 dB coupler Local 1 Connect the directional coupler to the point where the RF power is to be leveled Connect the power meter sensor to the coupled port of the 10 dB directional coupler 2 Press the ALC INT key to place the Signal Generator into internal ALC mode 3 Set the RF output level for a 15 dBm power meter reading on the power meter Allow the Power meter to auto range to the coupled power 15 dBm Once the power meter has stabilized press the RANGE HOLD key or set the range manually to prevent auto ranging The power meter should now be set to read power levels of 20 to 10 dBm on the set range 3 106 HP 8673H
186. he OUTPUT LEVEL RANGE and the OUTPUT LEVEL VERNIER so the sum of the RANGE display and the LEVEL meter equal the desired output power Stepping the range up or down allows the output level to be changed in 10 dB steps Adjusting the vernier enables the output level to be changed continuously for levels between 10 and 3 dB of the RANGE The program code used to set the ALC mode to internal is C1 Once the Signal Generator is set to internal ALC mode the output level can be set and read directly by the controller Internal ALC is set when the instrument is preset The VERNIER and RANGE settings and the RF output level the sum of RANGE and VERNIER can be read using the output active program code suffix To read the VERNIER setting 10 0 to 3 0 dBm send the program string VEOA and then read the VERNIER setting using the ENTER command The Signal Generator will send the setting in units of dBm If the setting is read as a string the format will be the program code VE followed by the VERNIER setting in dBm and then the units code DM The RANGE setting is read by sending the program string RAOA and then reading the RANGE setting using the ENTER command The Signal Generator will send the range in units of dBm 90 to 10 If the RANGE setting is read as a string the format will be the program code RA followed by the range setting in dBm and then the units code DM The RF output level is read by sending the program string LEOA and then reading th
187. he power at the remote point The Signal Generator will adjust the signal level at the RF output connector to maintain a constant level at the point where the signal is detected External ALC also enables external devices such as amplifiers mixers and other specialized devices to be inserted into the RF signal path with control of the final output level by the Signal Generator In applications where the external signal path has frequency dependent losses and or gains the RF signal at the end of the signal path will no longer have a constant amplitude over the Signal Generator s frequency range For example if a cable is used that has a constant 5 dB GHz loss a level error of 5 dB would occur after a 10 GHz frequency change The signal at the RF output connector of the Signal Generator has not changed but an extra 5 dB of attenuation is introduced in the signal path when the output frequency is changed The detection of the external signal level can be done using one of several methods The simplest method uses a crystal detector or Shottky diode which has an output voltage that is proportional to the detected power square law A positive or negative crystal detector may be used with equal results since the Signal Generator does an absolute value conversion on the feedback signal External ALC using a diode crystal detector or Shottky diode has the advantage of fast settling time In addition diode leveling is simpler and less expensive than
188. he start frequency Using the FREQ INCREMENT up or down key or the TUNE knob will change the RF frequency by the sweep step size HP 8673H Local Procedure cont d Remote Procedure Example Program Codes Comments Operation Detailed Operating Instructions Manual Sweep Mode conta Direct entry of a frequency using the numeric keypad will change the center frequency of the sweep This will reset the start and stop frequency and s et the current frequency equal tothe new start frequency The FREQ INCREMENT keys and the TUNE knob will tune the frequency between the start and stop frequency The FREQ INCREMENT keys and the TUNE knob will always operate just as in CW mode Setting the start frequency above the stop frequency will place the frequency at the higher start frequency when manual sweep is activated however counter clockwise rotation of the TUNE knob and the FREQ INCREMENT down key will always decrement the frequency whether the start frequency is set above or below the stop frequency Manual sweep mode is activated with the program code W3 The sweep can be reset with the program code RS Resetting the sweep will reset the sweep frequency to the start frequency The IF program code will produce a step toward the stop frequency even if the start frequency has been set above the stop frequency The UP program code will always produce an increase in the absolute frequency and DN will always produce a decrease in the ab
189. how 63 238 and should be left justified 4 Press the MHz units key to finish the sequence The FREQUENCY MHz display should show the entered frequency until the units key is released The FREQUENCY MHz display should be right justified when the units key is pressed The frequency could also have been entered as 063238 GHz or 63238 kHz The only difference is the placement of the decimal point and the units terminator Entering a frequency offset of zero will deactivate the frequency offset mode Remote The programming string for setting a marker is composed of the frequency offset program code the positive or negative frequency offset and the units terminator The offset frequency can be programmed in units of GHz MHz kHz or Hz To program a positive frequency offset of 63 238 MHz the possible program strings are FT 063238G2 or FT63 238MZ or FT63238KZ or FT63238000HZ The alpha non numeric characters can be sent as upper or lower case or even mixed upper and lower case A positive frequency offset does not require the plus sign before the offset frequency Program Applicable Code Units Offset Frequency Positive Offset Negative Offset Negative Offset Offset Frequency Preferred Program Code 3 103 Operation HP 8673H Detailed Operating Instructions Comments Programming Example Error Messages 3 104 Offset Frequency conta When using the Signal Generator as the local oscillator in
190. ht to check the product type for compliance with these require ments Note If test and measurement equipment is oper ated with unshielded cables and or used for meas urements on open set ups the user must ensure that under these operating conditions the radio fre quency interference limits are met at the border of his premises HP 8673H ig EE E E E E E E EE HY bbn Darety Considerations SAFETY CONSIDERATIONS GENERAL This product and related documentation must be reviewed for familiarization with safety markings and instructions before operation This product is a Safety Class I instrument pro vided with a protective earth terminal BEFORE APPLYING POWER Verify that the product is set to match the avail able line voltage and the correct fuse is installed SAFETY EARTH GROUND An uninterruptible safety earth ground must be provided from the main power source to the prod uct input wiring terminals power cord or sup plied power cord set Any interruption of the protective grounding conductor inside or outside the instrument or disconnecting the pro tective earth terminal will cause a poten tial shock hazard that could result in personalinjury Grounding one conduc tor of a two conductor outlet is not suffi cient protection In addition verify that a common ground exists between the unit under test and this instrument prior to energizing either unit Whenever it is likely that the
191. icate that one of the front panel keys has been pressed since the last time the status byte was cleared The bit is not set if the Signal Generator is in remote mode when a key is pressed The bit can be used in applications requiring the controller to know when a user changes one of the instrument parameters For example the bit can be used to indicate when a user has changed frequency so that measuring equipment under remote control can be retuned for another measurement Changes of the VERNIER are not indicated by this bit The RANGE up and down keys and the FREQ INCREMENT up and down keys will have this bit set once for each key press However holding the key down will increment or decrement more than one time even though the bit is set only once FRONT PANEL ENTRY COMPLETE This bit is used to detect the completion of a front panel data entry using the numeric keypad the TUNE knob or the FREQ INCREMENT up or down key The bit is set once the entry is completed For example the bit is set after the units key is pressed when setting the frequency Since front panel entry is disabled when in remote mode this bit is not set for entries during remote mode When used in conjunction with the FRONT PANEL KEY PRESSED bit the controller can determine when a user begins entering a front panel value and when the entry is complete The FRONT ENTRY COMPLETE bit can also be used to detect when the FREQ INCREMENT up or down key is released The bit
192. iding the entered span by the current number of steps Entering the number of sweep steps will recalculate the sweep step size by dividing the sweep frequency span by the entered number of steps The number of steps will be adjusted until the sweep step size is equal to or larger than the frequency resolution If the number of steps times the sweep step size does not exactly equal the frequency span the last sweep point the stop frequency will not be included The number of steps may be increased automatically by the Signal Generator to offset the effect of frequency resolution on the step size For example if the sweep span is set to 1 MHz and 400 steps are selected the number of steps will be increased to 500 steps This adjustment is made since 2 kHz steps would yield a span of 800 kHz while 3 kHz steps would provide a span of 1 2 MHz Since both of the resulting spans are incorrect the number of steps is increased to 500 to produce a 1 MHz span with 2 kHz steps The original entry will be retained for recalculation when other sweep parameters are changed The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program is used to set the number of sweep steps to the number specified by the variable called Expected The desired value must be between 1 and 9999 steps 10 SUB Sweep_steps Err Expected 20 OUTPUT 719 USING 2A MG Clear message from 8673 30 ENTER 719 USING 2A Message to clear any old mess
193. ifferent frequency bands An ALC UNLEVELED condition occurs when the intemal ALC circuitry cannot maintain leveling This can occur due to an instrument fault or because the instrument is set to level for an RF output level that is beyond its capability Calibrated output level is only guaranteed with the UNLEVELED annunciator extinguished When the UNLEVELED annunciator is lighted the Signal Generator s LVL meter will indicate approximate available power For example if the Signal Generator is capable of 9 dBm leveled power at a given frequency and the RF output level is set for 13 dBm the level meter will give an indication of 1 dBm to indicate that the maximum available power is 9 dBm The choice of RANGE and VERNIER settings can have a significant effect on some applications If a continuous 13 dB range about a specific output level is required the VERNIER alone can be used If 10 dB steps are required the RANGE up and down keys may be used to step the RF output level in 10 dB steps High VERNIER settings give the worst case performance for harmonics while the low VERNIER settings give the worst case performance for subharmonics For applications requiring lowest harmonics use a higher range setting to allow setting the VERNIER at a lower setting For example if an output level of 10 dBm is required with a minimum harmonic use the 0 dB range and the 10 dBm setting of the VERNIER HP 8673H Operation Detailed Operatin
194. ill clear both bytes after they are read To read the extended status byte the program code OS is sent and then the status byte and extended status byte are read into the controller Since the extended status bits are latched the extended status byte may indicate that a problem exists that has already been corrected For example if the RF output is turned off the NOT PHASE LOCKED bit and the ALC UNLEVELED bit will be set If the RF output is then turned on and the extended status byte read the NOT PHASE LOCKED and ALC UNLEVELED bit will still be set To read the current instrument status the status should be cleared CS and then the extended status byte will reflect current conditions Service Request SRQ The Signal Generator can generate a service request whenever one of the bits of the status byte is set However the bits must be enabled before a service request will be generated To enable a bit the corresponding bit of the Request Mask must be set to a one For example to generate a service request when the END OF SWEEP bit is set bit five of the Request Mask must be set to a logical one true The program string required to set bit 5 is RM16 since bit 5 has a weight of 16 see the status byte in Comments When the Signal Generator is first turned on the Request Mask is cleared so that a service request will not be generated The Request Mask value can be read by the controller so bits can be added or cleared from the present valu
195. ing format follo ws the front panel entry format To program a frequency display multiplier the program code MY is sent followed by the multiplier and the units XF The multiplier can be read by the controller using the output active program code suffix To read the multiplier send the program codes MYOA and then read the multiplier If the multiplier is read as a string the format will be the program code MY followed by the multiplier and then the units program code HZ 3 99 Operation HP 8673H Detailed Operating Instructions Example Program Codes Comments 3 100 Multiplier Mode conta To set a frequency display multiplier of 2 Local 1 Press the blue shift key to access the shifted functions The shifted functions are printed in blue above certain keys 2 Press the MULT key to indicate that a display multiplier is to be entered 3 Enter a 2 using the number keypad The entered value should be displayed in the FREQUENCY MHz display 4 Press the X FREQ units key to complete the sequence The FREQUENCY MHz display should show the entered multiplier 2 until the X FREQ key is released The entered display multiplier can be read by pressing the shift key and then pressing and holding the MULT key The entered multiplier will be displayed until the key is released Once a multiplier is entered all frequencies will be displayed after being multiplied by the entered multiplier The offset frequency if entered
196. inserted between 2 characters of a program code the program code would be invalid and any remaining characters in a string might be misinterpreted by the Signal Generator After receiving an invalid program code the Signal Generator requires a valid program code before it will respond to numeric entries Immediate Execution Mode ASCII characters can be accepted in the Deferred or Immediate execution modes Immediate Execution is the default mode at turn on It can be set if necessary by sending the program code 3 In this mode the Signal Generator produces an End of String EOS message at the end of each character and does not require one from the controller The Signal Generator processes each character before accepting the next one Therefore the Immediate Execution mode does slow down overail data transfer However the Signal Generator can switch faster after the final EOS message than it can in the other mode This is useful when the system controller is slow enough data rate lt 1000 bytes second that it cannot take advantage of the Deferred mode s transfer speed or when switching time independent of message length is more important than program execution speed Deferred Execution Mode This ASCII mode must be selected by sending the program code 2 In this mode the Signal Generator accepts strings up to 96 characters at a time executing the string upon receiving an EOS message The Signal Generator produces its own EOS m
197. ion 3 6 WMtrOGUCHOR siinide dia an a Ard Avion Peak z Specifications 13 ALC Automatic Level Control 3 6 Safety Considerations 13 Pulse Modulation lt a Manual Updates 13 Sweep Mode in Master Slave Configuration 37 Description 13 Operator s Checks 3 17 Options 1d Basic Functional Checks 3 17 Electrical Options 14 HP IB Functional Checks ioeina naudin ashina 3 25 Mechanical Options 4 Remote and Local Messages and the LOCAL Key 3 25 Miscellaneous Options an LS Receiving the Data Message 3 26 Accessories Supplied a 1 5 Sending the Data Message 3 26 Equipment Required but not Supplied 1 5 Local Lockout and Clear Lockout Set Local Electrical Equipment Available Messages 3 27 Recommended Test Equipment Clear Message 3 28 Abort Message os 3 28 Section 2 Status Byte Message 3 28 INSTALLATION Require Service Message 3 29 Status Bit Message 3 30 Introduction 2 1 Trigger Message a 3 31 Initial Inspection 24 Remote Operation Auxiliary Control 3 32 Preparation f r Use oe 21 AUX Input Lines 3 32 Power Requirements 21 AUX Output Lines 3 32 ae ee and Fuse Selection F Remote Operation HP IB 3 32 ower Cables ieee 28 waite HP IB Address Selection 22 anne T nE Interconnections 2 3 Local Mode o 3 33 Mating Connectors 2 4 1 S y Addressing 3 35 Frequency Reference Sensitivity Selection 24 Turn on Default Conditions 3 35 Operating Environment 24 Di splays
198. is error may be displayed when the SWEEP FREQ START key is pressed if tuning the instrument placed the sweep start frequency below the frequency range of the Signal Generator Indicates that the current sweep stop frequency is above the frequency range of the Signal Generator This error may be displayed when the SWEEP FREQ STOP key is pressed if tuning the instrument placed the sweep stop frequency above the frequency range of the Signal Generator Number of steps were adjusted to give even step size This ensures that the full sweep span is covered by adjusting the number of steps For example if the number of steps is set to 100 and the stop frequency is 6000 010 MHz setting the start frequency to 6 GHz will automatically adjust the number of steps to 10 to accommodate the minimum frequency resolution of 1 kHz Auto Peak malfunction This indicates that the instrument may require service 3 129 Operation HP 8673H Detailed Operating Instructions Description 3 130 Status Byte and Polling The status byte enables a remote controller to determine the instrument s status There is also an extended status byte which can be read by the controller to determine the state of most of the front panel annunciators Status Byte The status byte contains eight bits which correspond to certain conditions of the instrument Each bit is defined as follows BIT 1 BIT 2 BIT3 BIT 4 FRONT PANEL KEY PRESSED This bit is used to ind
199. ish the sequence The FREQUENCY MHz display should show the entered frequency until the units key is released The FREQUENCY MHz display should now be right justified The frequency could also have been entered as 4 5 GHz or 4500000 kHz The only differences are the placement of the decimal point and the selection of the selection of the appropriate units key pressed after the frequency has been entered using the numeric keypad Remote The programming string for setting the sweep delta frequency is composed of a program code numeric data and the units terminator The frequency may be programmed in units of GHz MHz kHz or Hz To program the Signal Generator delta frequency to 4500 MHz the possible program strings are FB4 5GZ or FB4500MZ or FB4500000KZ or FB4500000000HZ The alpha characters can be sent as upper or lower case or even mixed upper and lower case Setting the sweep delta frequency will not change the CW frequency when sweep is off Program Function Applicable Code Units DF AFrequency Preferred Program Code Operation HP 8673H Detailed Operating Instructions Comments Programming Example 3 60 Delta Frequency Sweep cont d Due to the use of frequency multiplication to generate frequencies above 6 6 GHz the sweep start and stop frequencies recalculated when the sweep delta frequency is entered may not be set precisely to one half of the sweep delta frequency below or above the cente
200. k operation occurs whenever the frequency has changed by more than 50 MHz from the last frequency where an Auto Peak operation was performed An Auto Peak also occurs whenever Auto Peak is switched from disabled to enabled when pulse mode is enabled when an FM deviation range is changed when the RF output is tumed on and when the output level VERNIER causes a change greater than 0 4 dB Pulse modulation requires Auto Peak to be enabled to guarantee the published specifications See the pulse modulation detailed opera ting instructions for more information regarding pulse modulation and Auto Peak To perform an Auto Peak operation 1 Press the AUTO PEAK key to disable Auto Peak operations If the key indicator is off this step is not required 2 Press the AUTO PEAK key again to enable Auto Peak operations The key indicator should now be lighted The Auto Peak operation is performed immediately after the Auto Peak key is pressed if the key indicator was off Auto Peak should be enabled at all times to provide optimum RF output signals However for faster frequency switching times or digital sweeps Auto Peak may be disabled at the expense of slightly degrading the RF output signal There are three programming codes associated with the Auto Peak operation K 0 disables all Auto Peak operations Selecting pulse modulation will automatically re enable Auto Peak The disable programming code must follow the selection of pulse modulation mod
201. l 5 kHz sine wave Can be connected to front panel AM IN to provide AM markers 6 PEN LIFT BNC female connector TTL high lifts pen TTL low lowers pen 100 ms delay to lift or lower pen in single sweep mode RF OUT A348 For Options 004 and 005 only 50Q Type N female output connector 10 MHz OUT A3U8 0 dBm nominal into 50Q can be used as an external timebase FREQ STANDARD Output A3J9 10 MHz into 50Q at 7 dBm nominal from the internal frequency standard except when INT EXT switch is in the EXT position 9 Jumper A3W3 Normally connects the 3 16 Internal Frequency Standard Output A3J9 to the External Frequency Standard Input A3J10 HP 8673H FREQ STANDARD Input A3J10 Normally connected by A3W3 to A3J9 Also used to connect an external frequency standard of 5 or 10 MHz at 0 dBm to the Signal Generator FREQ STANDARD INT EXT Switch Normally left in the INT position Removes power from internal frequency standard when in the EXT position 12 Line Power Module Permits operation from 100 120 220 or 240 Vac The number visible in the window displays the nominal line mains voltage for which the module is set see Figure 2 1 The protective grounding conductor connects to the Signal Generator through this moduie The line power fuse is part of this module and is the only part to be changed by the operator 100 MHz OUT A3U7 0 dBm nominal into 50 Can be used
202. l be filled with the required parameters for the pulse injection circuitry Once the scratch pad memory contains the data for the current frequency an Auto Peak operation will not occur for any change in RF output level A frequency change will erase the scratch pad memory so this process must be repeated at the new frequency Pulse modulation uses a sample and hold system to maintain pulse level accuracy A capacitor is used to hold the automatic level control ALC circuit setting between pulses to reduce the time required for output level settling at the next pulse When pulse and amplitude modulation are used together the capacitor has the effect of reducing the effective AM bandwidth The reduction in AM bandwidth is explained under AM detailed operating instructions When pulse modulation is selected with no input pulse the level meter will drift This is a normal occurrence due to the limitations of the sample and hold circuitry Due to the Auto Peak operations performed during pulse modulation frequency switching time is slowed to approximately 100 milliseconds Disabling Auto Peak will speed frequency switching time at the expense of degradation of risetime and overshoot Pulse specifications only apply when Auto Peak is enabled The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The program will set the pulse mode to the mode specified by the variable Mode 10 SUB Pulse_mode Err Mode 30 SELEC
203. least 50 ns The output level indicated on Signal Generator meter may also vary gt 1 dB as the UNLEVELED annunciator comes on This is normal instrument operation indicating a pulse unleveled condition Press PULSE OFF and disconnect the oscilloscope and test oscillator from the Signal Generator Memory Check 31 52 Set FREQUENCY to 11 GHz and Output Level RANGE to 20 dB Turn the Signal Generator s LINE switch to STBY wait 30 seconds then turn the LINE switch to ON Verify that the FREQUENCY MHz display shows 11000 000 MHz and the RANGE dB display shows 20 dB Message Check 53 54 55 Press RCL 0 to preset the Signal Generator to a known state Enter a FREQUENCY of 30 GHz out of range and verify that the FREQUENCY DISPLAY remains at 9000 MHz and the MESSAGE key indicator turns on Press and hold the MESSAGE key The FREQUENCY MHz display should show message code 01 frequency out of range Release the MESSAGE key Verify that the key indicator tums off 3 24 HP 8673H Operation lt gt OPERATOR S CHECKS 3 19 HP IB Functional Checks 4E Description These procedures check the Signal Generator s ability to process or send the HP IB messages described in Table 3 3 Only the Signal Generator a controller and an HP IB interface are needed to perform these checks These procedures do not check if all Signal Generator program codes are being properly interpreted and executed by the instr
204. lete by the time the extended status is read If a selected device clear i e CLEAR 719 or a device clear i e CLEAR 7 are used a settling time of about 2 seconds is required before the extended status byte is valid and the source is settled Setting the Signal Generator to 9 GHz before the clear will allow the preceding procedure to be followed starting with step 2 after the preset The SOURCE SETTLED bit is set once the affected parameter has settled If a clear status is executed before this bit is set from a previous command the bit will be set after the status byte has been cleared and before the parameter being programmed has changed For example if the instrument is preset and the status cleared as part of a frequency change before the Signal Generator has settled the SOURCE SETTLED bit will be set by the instrament preset before the frequency change is complete If the bit is being checked before proceeding the program will continue before the frequency change has settled Status bits are set asynchronously whenever the corresponding condition occurs If a condition occurs between the time the ourput extended status program code is received and the time both status bytes are read the status byte will reflect the changed condition by setting the appropriate bit Note that once a bit is set only a clear status or reading the extended status can clear it When the ENTRY ERROR bit is enabled to cause a service request the message must be
205. level from 60 to 47 dBm Remote The programming string for setting the RF output level is composed of a program code numeric data and the units terminator The RF output level may be programmed directly or the RANGE and VERNIER may be programmed separately To program the Signal Generator to a level of 56 dBm the possible program strings are LE 56DM or RA SODBVE 6DM In addition the program code could be AP or PL instead of LE The alpha characters can be sent as upper or lower case or even mixed upper and lower case The Signal Generator RF output level is valid once the SOURCE SETTLED bit of the status byte is set see comments The units terminator could be DB or DM The Signal Generator accepts either terminator for all power related settings Program Applicable Code Units RA Output Level Range LE RF Output Level DB AP RF Output level DM PL RF Output level Preferred Program Code HP 8673H Comments Programming Example Error Messages Operation Detailed Operating Instructions Range Output Level conta The 0 to 90 dB ranges directly control a 90 dB step attenuator The 0 and 10 dB ranges correspond to an internal attenuator setting of 0 dB The 90 dB range corresponds to an attenuation setting of 90 dB The 10 dB range is used by the automatic level control ALC circuitry to enable the VERNIER to directly control the RF output level between 0 dBm up to a maximum possible level of 13
206. ll Err Expected Dwell in milliseconds 20 OUTPUT 719 USING 2A MG Clear message from 8673 30 ENTER 719 USING 2A Message I to clear any old messages 40 OUTPUT 719 USING 2A DDD 2A SP Expected SS Set size 50 OUTPUT 719 USING 2A MG Get any error message 60 ENTER 719 USING 2A Message 70 SELECT VAL Message 80 CASE 8 90 Err 1 100 DISP WARNING The specified dwell time is out of range 110 CASE ELSE 120 Err 0 130 END SELECT 140 150 SUBEND The following message numbers may be displayed when setting the sweep dwell time Each message is explained as it pertains to setting the dwell time For a more complete description of the messages see the MESSAGES detailed operating instructions 08 The entered dwell time is not within the range of 1 millisecond to 255 milliseconds 3 67 Operation HP 8673H Detailed Operating Instructions Description Local Procedure Frequency CW When sweep modes are off the Signal Generator can be set to any frequency within its range The frequency can also be tuned in any step size that will result in a new frequency within its specified range All valid frequencies can be remotely programmed or entered manually via the numeric keypad or tuning controls For applications requiring setting a single specific frequency direct entry using the numeric keypad is the most efficient method However for tuning over a specific range or observing several frequencies the
207. ll continue stepping the RANGE until the key is released The RANGE setting represents the maximum level available using that range The VERNIER control will allow setting output levels from 10 dB below to 3 dB above the RANGE There is a slight overlap of output level settings due to the 13 dB range of the VERNIER control For best results the VERNIER setting should be within the range of 10 to 0 dBm VERNIER settings from 0 to 3 dBm are available for observing a continuous range up to 3 dB above the RANGE setting without changing the RANGE setting 2 Adjust the VERNIER control until the sum of the RANGE and the level meter reading equal the desired RF output level The VERNIER can be used to vary the output level continuously about the set level or the RANGE up or down key can be used to step the output level in 10 dB steps If the UNLEVELED annunciator lights for high output level settings the level meter will indicate maximum available output power This should only occur when output levels above the specified maximum leveled power are set For example if the RF output level is set to 13 dBm and the level meter reads 4 dBm with the UNLEVELED annunciator lighted only 9 dBm of output power is available at that frequency The Signal Generator accepts any RF output level between 101 9 and 13 dBm RF output levels above the specified maximum leveled power may not be available at all frequencies Programming the RF output level can
208. lues The initialized control setup will then be stored in all of the registers The Signal Generator might be useable but does require service Operation 3 11 Frequency Standard Selection A FREQ STANDARD INT EXT switch and two connectors are located on the rear panel A jumper normally connects the FREQ STANDARD INT connector A3J9 to the FREQ STANDARD EXT connector A3J10 The FREQ STANDARD EXT connector can accept a reference signal to be used instead of the Signal Generator s internal frequency standard The internal frequency standard is a 10 MHz signal at 7 dBm nominal with an aging rate of lt 5 x 10 10 day after warm up typically 24 hours When the FREQ STANDARD INT EXT switch is in the INT position and the jumper is connected between A3J9 and A3J10 the internal reference is enabled When the FREQ STANDARD INT EXT switch is in the EXT position and the jumper is disconnected from the FREQ STANDARD EXT connector a frequency standard of 5 or 10 MHz at 7 to 13 dBm 0 to 1 Vrms into 50Q can be connected NOTE The EXT REF status annunciator on the front panel will light when an external reference is being used Also the UNLOCKED status annunciator may light if the external reference is not of sufficient accuracy in frequency or has an insufficient power level The external reference must be within 200 Hz of 10 MHz or 100 Hz of 5 MHz for reliable locking to occur If the external reference level is not within
209. malfunction is severely FM overmodulated has the FREQ STANDARD INT EXT switch in the EXT position with no external frequency reference or has the RF output off the NOT PHASE LOCKED status bit will be set This bit is not valid after a frequency change until the SOURCE SETTLED bit is set The UNLOCKED annunciator on the front panel corresponds to this bit BIT6 POWER FAILURE ON If the mains power to the Signal Generator is interrupted and then returned this bit will be set The bit can be used to verify that the line main has not been interrupted since the last time the status byte was checked BIT7 ALC UNLEVELED If the Signal Generator output level is not calibrated as indicated by the front panel UNLEVELED annunciator or the amplitude modulation circuitry is being overmodulated or the RF output is off the ALC UNLEVELED bit in the extended status byte will be set BIT 8 This bit is always set to zero The status byte and the extended status byte can only be read using a controller All but one of the extended status bits can be read also on the front panel The POWER FAILURE ON bit can only be read using a controller The SELF TEST FAILED will be indicated by a message just after the instrument is turned on All of the other bits have a status annunciator that is turned on whenever the appropriate conditions exist A controller can be used to poll the Signal Generator while in remote mode to determine when a key is pressed or when the ext
210. med RF output VERNIER RANGE or both is outside the Signal Generator s range 3 150 HP 8673H Description Local Procedure Remote Procedure Operation Detailed Operating Instructions Vernier Output Level The RF output level of the Signal Generator is set using the RANGE and VERNIER controls The RANGE controls change the RF output level in 10 dB steps and the VERNIER changes the RF output level continuously over a 13 dB range The sum of the output level RANGE and VERNIER is the actual RF output level In local mode the output level meter displays the VERNIER setting In remote mode the output level meter displays the remote setting When going from local to remote mode the RF output level should not change by more than 0 1 dB When changing from remote to local mode the RF output level will return to the front panel setting of the VERNIER which may change the RF output level by as much as 13 dB The RANGE setting will not change for either transition When setting RF output levels above the specified maximum power an UNLEVELED condition may occur due to insufficient available power When this occurs the output level meter will indicate the maximum available power Increasing the VERNIER setting will not change the displayed level on the output level meter To set the RF output level using internal ALC 1 Press the RANGE up or down key until the desired RANGE appears in the RANGE dB display Holding the key down wi
211. mote Procedure 3 102 Offset Frequency For applications that require a constant frequency offset to be used when setting the Signal Generator frequency a frequency offset can be entered For example using the Signal Generator as a local oscillator with a frequency offset equal to the IF frequency allows both the RF source and the local oscillator to be set to the same frequency Because of the offset frequency on the local oscillator the actual frequency will be lower or higher than the programmed frequency which will maintain the correct IF frequency Offset frequency is only available on system compatible instruments To determine if a specific Signal Generator is system compatible see paragraph 3 2 System Compatibility Once the desired positive or negative offset is entered the frequency displayed by the Signal Generator will be different from the actual RF frequency by the frequency offset Entering or programming frequencies with frequency offset enabled will automatically calculate the required output frequency according to the frequency offset To set a frequency display offset 1 Press the blue shift key to access the shifted functions The shifted functions are printed in blue above the associated key 2 Press the OFFSET key if the displayed frequency is to be above the actual output frequency Otherwise press the OFFSET key if the displayed frequency is to be below the actual offset frequency 3 Enter the desired of
212. mpatible instruments See paragraph 3 2 System Compatibility for more information about system compatibility The sweep stop frequency has been set equal to the start frequency No sweep will occur when a sweep mode is selected Indicates that the desired sweep start frequency is below the frequency range of the instrument This error may be displayed when the SWEEP FREQ STOP key is pressed if tuning the instrument placed start frequency below the frequency range of the Signal Generator Indicates that the desired sweep stop frequency is above the frequency range of the instrument This error may be displayed when the SWEEP FREQ STOP key is pressed if tuning the instrument placed the stop frequency above the frequency range of the Signal Generator Number of steps were adjusted to give even step size This ensures that the full sweep span is covered by adjusting the number of steps For example if the number of steps is set to 100 and the stop frequency is 6000 010 MHz setting the start frequency to 6 GHz will automatically adjust the number of steps to 10 to accommodate the minimum frequency resolution of 1 kHz Auto Peak malfunction This indicates that the instrument may require service 3 147 Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 148 System Automatic Level Control External ALC enables the Signal Generator to level the signal at a point other than the output of the Signal
213. ms an absolute value function on the input voltage For more information on each of the Automatic Level Control functions see the detailed operating instructions 3 15 Pulse Modulation The automatic execution of the AUTO PEAK function by the instrument s internal microprocessor ensures that key power and pulse specifications are met for nearly all circumstances see Section 3 12 Three conditions that may necessitate a user activated AUTO PEAK are load changes extreme frequency changes and in rare circumstances frequency changes less than 50 MHz a Changes of load impedance can shift the center frequency of internal filters and necessitate another AUTO PEAK operation This could occur if highly reactive loads are switched in and out in automatic test systems b Large frequency changes cause extreme changes in the self heating of internal YIG filters Although most of the resulting drift occurs in 15 20 seconds complete settling may take up to 15 minutes Some experimentation may be needed to determine when AUTO PEAK is necessary for this type of measurement c Finally on rare occasions pulse overshoot parameters may drift out of specified range for frequency changes less than 50 MHz To be confident of obtaining warranted instrument performance perform an AUTO PEAK operation just before each measurement is taken Another automatic instrument function determines the optimum injected pulse amplitude to the YTM This
214. n is a specification that indicates how much the power level at the FM IN connector may have to be adjusted to provide the desired and indicated FM peak deviation This correction is required due to the frequency response characteristics of the FM circuitry for rates other than 100 kHz The following program is written in BASIC for HP 9 000 Series 200 or 300 controllers The program will set the FM range to an appropriate setting and return the peak voltage required into 50 ohms for the FM peak deviation specified by the variable called Deviation 10 SUB Fm_deviation Err Deviation V_required Deviation is in MHz 20 30 IF Deviations10 THEN 40 Dev D7 Code for 10 MHz peak deviation 50 V_required Deviation 10 In peak volts into 50 ohms 60 ENDIF 70 IF Deviations3 THEN 80 Dev D6 Cade for 3 MHz deviation 90 V_required Deviation 3 In peak volts into 50 ohms 100 ENDIF Operation Detailed Operating Instructions Programming 110 HP 8673H Frequency Modulation conta IF Deviations1 THEN Example 120 Dev D5 Code for 1 MHz deviation cont d 130 V_required Deviation 1 In peak volts into 50 ohms 140 END IF 150 IF Deviations THEN 160 Dev D4 Code for 300 kHz peak deviation 170 V_required Deviation 3 l In peak volts into 50 ohms 180 END IF 190 IF Deviations 1 THEN 200 Dev D3 Code for 100 kHz deviation 210 V_required Deviation 1 I In peak volts into 50 ohms 220 END IF 230 IF Deviations 03 THEN
215. n read Error Following are notes about certain error codes Messages 03 Invalid multiplier entry for system compatible instruments See paragraph 3 2 System Compatibility for more information 90 Auto Peak malfunction If error 90 occurs during pulse mode pulse performance may not be correct Clear the message and attempt an Auto Peak function If error 90 occurs again service is required Table 3 8 Error Messages Definition 00 NOERROR Messages 01 09 are operator errors The entry is ignored and the previous values are retained FREQUENCY OUT OF RANGE FREQ INCR OUT OF RANGE MULTIPLIER ENTRY OUT OF RANGE CANNOT STORE REGISTER 0 STEP SIZE OUT OF RANGE NUMBER OF STEPS OUT OF RANGE DWELL OUT OF RANGE MARKER NUMBER NOT 1 5 Messages 10 16 are soft errors that result from unusual combinations of sweep entries A message is displayed and all entered values are stored in anticipation that further entries will resolve the conflict START FREQ STOP FREQ No sweep SWEEP SPAN RESULTS IN START FREQUENCY OUT OF RANGE Truncated sweep will result SWEEP SPAN RESULTS IN STOP FREQUENCY OUT OF RANGE Truncated sweep will result NUMBER OF STEPS ADJUSTED TO GIVE STEP SIZE IN EVEN kHz Press STEP to see result 3 98 Definition STEP SIZE TOO SMALL FOR SPAN Press STEP to see result maximum number of steps is 9999 STEP SIZE gt SPAN Step size is set to span BAND CROSSING IN AUTO SWEE
216. ncy Sweep cont d The following message numbers may be displayed when setting the sweep delta frequency Each message is explained as it pertains to setting sweep delta frequency For a more complete description of the messages see the MESSAGES detailed operating instructions 01 Entered delta frequency is not within the capability of the Signal Generator 11 Indicates that the desired sweep start frequency is below the frequency range of the instrument The start frequency is set to the lowest valid frequency 12 Indicates that the desired sweep stop frequency is above the frequency range of the instrument The stop frequency is set to the highest valid frequency 13 Number of steps were adjusted to give even step size This ensures that the full sweep span is covered by adjusting the number of steps For example if the number of steps is set to 100 and the delta frequency is set to 10 kHz the number of steps will be reset to 10 to accommodate the minimum frequency resolution of 1 kHz Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 62 Diode Automatic Level Control Automatic Leveling Control ALC is used to maintain a constant power control at a given point External ALC enables the Signal Generator to level the signal at a point other than the output of the Signal Generator The signal level must be detected using an external detector that provides a DC signal that is proportional to t
217. ncy out of range 130 CASE 10 140 Err 10 150 DISP WARNING Sweep start and stop frequency are equal 160 CASE 90 Auto Peak Error 170 Err 90 180 DISP WARNING Auto Peak error Service may be required 190 CASE ELSE 200 Err 0 Other errors not applicable 210 END SELECT 220 230 OUTPUT 719 USING 4A FAOA Requests current start freq 240 ENTER 719 USING K Set_freq Frequency in Hz 250 Set_freq INT Set_frea 1000 1000 Convert to MHz 260 270 IF ABS Set_freq Frequency gt 001 AND ErreO THEN 280 DISP WARNING Requested frequency rounded to Set_freq 290 ENDIF 295 SUBEND End of subroutine To prevent roundoff errors from occurring the following subprogram may be used to adjust a frequency so that it is always within 1 kHz of the desired frequency 300 SUB Round_off Err Expected l Expected frequency in MHz 310 Err 0 l Initialize Err 320 Band 5 330 340 IF Expected lt 18600 001 THEN Band 3 350 IF Expected lt 12300 001 THEN Band 2 360 IF Expected lt 6600 001 THEN Band 1 370 380 Baseband INT Expected 1000 Band 1000 Rounded fundamental 390 Round_down Baseband Band 400 IF Round_down lt gt Expected THEN Requires rounding 410 Round_up Baseband 001 Band 420 IF ABS Round_down Expected lt ABS Round_up Expected THEN 430 Expected Round_down Minimum error is round down 440 ELSE 450 Expected Round_up Minimum error is round up 460 ENDIF 470 ENDIF 480 SUBEND 3 128 HP 8673H P
218. nd retum the peak voltage required into 600 ohms for the AM depth specified by Depth 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 SUB Am_depth Err Depth V_required Depth is in SELECT Depth CASE lt 30 Depth A2 Code for 30 depth V_required Depth 30 In peak volts into 600 ohms CASE lt 100 Depth A3 Code for 100 depth V_required Depth 100 In peak volts into 600 ohms CASE ELSE Err 1 DISP Desired AM depth is greater than 100 END SELECT OUTPUT 719 USING 2A Depth f SUBEND There are no messages associated with the setting of amplitude modulation 3 47 Operation HP 8673H Detailed Operating Instructions Description Local Procedure Remote Procedure 3 48 Auto Peak The Signal Generator uses an internal tracking filter for increased spectral purity and for rejecting unwanted multiplication products when generating frequencies above 6 6 GHz If the passband of the tracking filter is off by as little as 10 MHz maximum available power is reduced pulse modulation is distorted and the frequency modulation sidebands are filtered asymmetrically The tuning accuracy of the internal tracking filter must be better than 0 1 to avoid these problems Because of nonlinearities hysteresis and temperature sensitivities of the tuning the filter must be fine tuned with an Auto Peak operation to center the passband of the tracking filter The Auto Pea
219. ng condition to set the RQS bit true This message is executed immediately and does not require an End of String message to be sent At turn on the Request Mask is cleared that is set to 0 Sending the Request Mask Value a Data Message After receiving an OR program code Output Request Mask and when addressed to talk the Signal Generator will send a single binary word 8 bits that describes the present state of the mask The bit pattern can be interpreted with the information in Figure 3 11 NOTE This byte is sent with the bus EOI line true thus terminating the message 3 42 Sending the Status Byte Message After receiving a Serial Poll Enable bus command SPE and when addressed to talk the Signal Generator sends a Status Byte message The message consists of one 8 bit byte of which 7 bits correspond to the pattern and descriptions for the Request Mask The remaining bit bit 7 is the RQS Request Service bit see Figure 3 11 The RQS bit is set when one of the other seven conditions exists and that condition has been enabled by the Request Mask Bits 1 6 and 8 might be true regardless of conditioning by the Request Mask However if a condition has not been selected by the mask it cannot cause the RQS bit to be set true Operation Extended Status Byte A second status byte is available but can only be accessed via the Output Status function see explanation under Sending the Data Message Bit 3 of the Status Byt
220. ng service 3 133 Operation HP 8673H Detailed Operating Instructions Remote Procedure cont d Program Codes Comments 3 134 Status Byte and Polling conta Parallel Poll The parallel poll PPOLL is used to allow several instruments to respond with the service request status on a single bus line Since there are e ight bus lines up to eight groups of instruments can be polled at the same time By testing the data lines after a parallel poll the group generating a service request can be quickly identified and then the instruments in that group can be serial polled until the instrument s requiring service is located In a system with eight instruments this reduces the number of polls from eight serial polls to one parallel poll and then a single serial poll The controller assigns a data line and the parallel poll sense using a parallel poll configure command The assigned data line is the line that the Signal Generator will output the SRQ if it is set The sense determines whether the active true value will be a logical zero or a logical one For example assigning the Signal Generator parallel poll response to data line five and the sense to false will cause the Signal Generator to output a false signal on data bus line five when the parallel poll occurs if the SRQ bit is set Program Code cs OR Os RM i ar 8 lz le Ts la J3 128 64 ee ee ee Description Clear status and extended status
221. ng the correct digits until the frequency displayed in the FREQUENCY MHz display is correct 3 Press the appropriate units key The frequency can be entered in GHz MHz or kHz Once the units key is pressed the displayed frequency will be adjusted to display MHz and the sweep start frequency will be set The sweep start frequency will continue to be displayed until the units key is released The actual frequency displayed after releasing the units key will usually not be the entered frequency If sweep mode is off the displayed frequency will indicate the frequency halfway between the new start frequency and the stop frequency If auto sweep is on the sweep will be reset and then continue using the new start frequency If single sweep is on the sweep will be reset and the sweep will remain armed at the new start frequency If manual sweep is on the sweep frequency will be reset to the start frequency To check the current sweep start frequency press and hold the SWEEP FREQ START key The FREQUENCY MHz display will display the sweep start frequency as long as the key is held When any sweep mode is turned off the CW frequency will be set to halfway between the start and stop frequencies equal to the sweep center frequency 3 125 Operation HP 8673H Detailed Operating Instructions Remote Procedure Example 3 126 Start Frequency Sweep cont d The Signal Generator accepts any sweep start frequency within its specified fr
222. ng using the HP 432A B HP 435B HP 436A HP 437B and HP 438A power meters are given in the following table ALC Typical Settling Times Power Meter Power 10 dB Step to Step Range dBm Sensor Within 1 dB Response HP 432A B 20t0 10 HP478A 400 ms Overdamped HP 435B 10 to 20 HP 8485A 550 ms Critically Damped 15 3s Underdamped 20 5s Underdamped 25 Unstable come HP 436A Critically Damped Underdamped Unstable HP 8484A Critically Damped Underdamped Unstable HP 437B HP 438A Filter No All Ranges Ow HP 8485A Critically Damped 3 to 9 Underdamped 0 to 2 HP 8484A Critically Damped 3 to 9 7 Underdamped The HP 437B and HP 438A auto filter mode will select filters automatically depending on range Using the manual filter mode can provide faster ALC settling time The Signal Generator range selected will have a direct affect on ALC The range selected depends primarily on the losses and gains in the RF signal path In most applications the ALC dynamic range is limited by the maximum RF power available at a given frequency For example with 15 dB of loss in the signal path the Signal Generator must compensate with at least 15 dB of additional RF output power With no internal attenuation 0 or 10 dB ranges the Signal Generator would have to supply 15 dBm for a leveled signal at 0 dBm Since the maximum RF output power is specified at less than 13 dBm the Signal Generator may not be able to supply the re
223. nished when the bit is set HP 8673H Program Codes Comments Programming Example Error Messages p Operation Detailed Operating Instructions Auto Peak cont d Program Description Code KO Disables Auto Peak Operations Enables and Performs Auto Peak Operation Performs Auto Peak Operation Without Settling K2 Preferred program code Auto Peak operations will produce small perturbations in the output level during peaking as the filter passband is adjusted If the tuning is too far off to be centered by the Auto Peak operation message 90 will be issued to indicate that the filter tracking requires adjustment When Auto Peak operations are disabled the filter fine tuning is not changed This feature can be used to achieve faster frequency switching time by performing a peak at the destination frequency and then disabling peaking The frequency switching time will then be minimized since an Auto Peak operation will not have to be performed Wide band sweeps can also use this feature to maintain power level at the higher frequencies by peaking at the higher frequency band and then disabling Auto Peak operations Output power typically decreases with increasing frequency The Auto Peak operation is slowed when any FM range is selected FM is not completely turned off when an Auto Peak occurs due to the relatively long tum off time required by the FM circuitry Instead the FM range is set to the lowest deviation
224. nt d Example Program Codes Comments Operation Detailed Operating Instructions Step Size Sweep cont d The actual step size can be read by the controller using the output active program code suffix To read the current step size the program string SPOA or SSOA is sent and then the step size and the number of steps must be read Since step size and the number of steps are directly related both are sent when the output active program code suffix is used If read as a string the format is the program code SP followed by the sweep step size in fundamental units Hz and the units terminator Hz a comma and the program code SP followed by the current number of steps and the units terminator SS To set the sweep step size to 455 kHz Local 1 Press the STEP key 2 Key in 455 using the numeric keypad The FREQUENCY MHz display should show 455 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the kHz units key to finish the sequence The FREQUENCY MHz display should show the calculated number of steps on the left half of the display and the entered or adjusted sweep step size on the right half of the display The message key will light if the sweep step size is adjusted to indicate the change from the desired value The sweep step size could also have been entered as 455 MHz or 000455 GHz The only difference is the placement of the decimal point and the units key press
225. o H C Ta o i a oya i 98 o fitiorrftol v 10 0 TOE a ok O KE Pe i of ii if olfo L 2 ofif1 oj 4 M 13 0 EEEo N 7 14 o tiititii4 0 7 15 lo 0 0 9 P 0 6 To foo a0 4 q ae iio lolio AR 2 18 Eee rE es 3 Eg tao E Eo eT 4 20 Poog e U 5 21 i fTorift o V 6 2 CIOL TA W 7 1io0ol0o 0 X 8 of ott Y 9 SAE N E 1 TEPSA c Remove the A2 Assembly s protective cover The A2 Assembly is located just forward and to the left of the fan as viewed from the rear Installation d Locate the A2A9 Frequency Output HP IB Assembly This assembly can be recognized as having one black and one white printed circuit board extractor e Set the switches to the desired HP IB address in binary or the Talk Only or Listen Only setting The switch is illustrated in Figure 2 3 If both the Talk Only and the Listen Only switches are set to 1 the Talk Only setting overrides the Listen Only setting Setting the address switch to Talk Only or Listen Only selects a unique HP IB address Talk Only 50 Listen Only 40 Talk Only and Listen Only are used when the Signal Generator is in a master slave configuration See the Detailed Operating Instructions in Section 3 for more information HP IB ADDRESS FRONT PNL ENABLE T aS ADDRESS LISTEN ONLY DARRA MSB LSB Figure 2 3 HP IB Address Switch Shown as Set by the Factory f To confirm the address setting turn on the Signal Generator and press and hold the LOCA
226. o STBY then to ON to turn the SRQ annunciator off HP 8673H Operation gt OPERATOR S CHECKS HP IB Functional Checks cont d Trigger Message Note Operator s Response Operator s Response This check determines if the Signal Generator responds to the Trigger message Description Serles 200 300 HP 85B BASIC Send the Remote message REMOTE 719 REMOTE 719 Send a Data message to set the OUTPUT 719 OUTPUT 719 Signal Generator s frequency to FR 9999 MZ FR 9999 MZ 9999 MHz Set the Signal Generator s frequency OUTPUT 719 OUTPUT 719 increment to 1111 MHz FI 1111 MZ FI 1111 MZ Check that the Signal Generator s frequency is set to 9999 MHz Then press the Signal Generator s FREQ INCR key to check for an increment of 1111 MHz This keyboard function is possible in the remote state even if local lockout is enabled Configure the Signal Generators OUTPUT 719 CT DN OUTPUT 719 CT DN trigger response to be an INCREMENT down function that is DN Send a Trigger message TRIGGER 719 TRIGGER 719 Check that the Signal Generator s frequency changes to 8888 MHz 3 31 Operation HP 8673H lt a gt 3 20 REMOTE OPERATION AUXILIARY 3 22 AUX Output Lines CONTROL The AUX connector also has a ground line and three F TTL compatible output lines The output lines are 3 21 AUX input Lines normally held at the high TTL level The End of Sweep A limited number of instrument f
227. occurs during an AUTO PEAK operation and for vernier power level changes 20 4 dB During this Operation operation the instrument switches briefly to CW for about 200 us Pulse mode is then re enabled and the injected pulse amplitude is the correct value to produce fast risetime pulses Frequency switching speed is slowed to about 100 ms by this process If these bursts of CW power are objectionable they can be eliminated by exploiting the following feature At any one frequency when the vernier is used to change the output power level by more than 0 4 dB a scratch pad memory stores the correct injected pulse amplitude for that power level Subsequent operation at that power level uses the scratch pad data instead of switching to CW to update the pulse control parameters For more information on this feature and on Pulse Modulation in general see the detailed operating instructions 3 16 Sweep Mode in Master Slave Configuration In a Master Slave configuration two signal generators are interconnected to obtain two swept microwave signals at a fixed offset from each other The two instruments are interconnected through the Hewlett Packard Interface Bus HP IB The MASTER is set to HP IB address 50 and the SLAVE unit is set to HP IB address 40 The desired sweep start and stop frequencies are set to identical frequencies on both the master and slave instruments Desired offsets are then entered on THE SLAVE UNIT USING THE
228. of each Status Byte Bits in the main Status Byte are cleared upon execution of Require Service SRQ Trigger Configuration 70 dB the Output Status function or the Clear Status CS 0 0 dBm program code Bits on the Extended Status Byte are ON cleared by removing the causing condition and LVL performing the Output Status function AM FM and Pulse OFF Modulation 9000 000 MHz 1 000 MHz 8000 000 MHz 10 000 000 MHz 2000 000 MHz OFF OFF 100 steps 20 000 MHz 20 ms ON 3 34 Receiving the Clear Message The Signal Generator responds to the Clear message by assuming the settings detailed in Table 3 5 The Signal Generator responds equally to the Selected Device Clear SDC bus command when addressed to listen and the Device Clear DCL bus command whether addressed or not The Clear message clears any pending Require Service message 3 39 Operation gt 3 35 Receiving the Trigger Message The Signal Generator responds to a Trigger message only if a response has been pre programmed see Configure Trigger Otherwise it ignores a Trigger message It responds equally to a Trigger message with bus command GET and a Data message with program code TR Trigger Configure Trigger The Signal Generator s response to a Trigger message is set when it receives a Data message containing the program code CT followed by one valid program code For example CTW6 causes a single s
229. ont panel entries i Talk Only Mode If the internal address switches are set to a valid Talk address and the Talk Only switch is set to 1 the Signal Generator is placed in the Talk Only mode In this mode the instrument is configured to send Data messages whenever the bus is in the data mode It can also send the Status Byte message in response to a serial poll The Signal Generator s Talk Only address can also be set from the front panel by keying in 5 0 then pressing the STO key and the LOCAL key Note that the FRONT PNL ENABLE switch on the internal HP IB address switch must be set to 1 to allow front panel entries 3 28 Turn on Default Conditions Several HP IB parameters are reset at turn on The parameters and their default conditions are listed below HP IB Local Mode gt Immediate Execution Mode o Unaddressed Trigger Configuration cleared e Request Mask cleared e SRQ cleared Operation lt gt 3 29 Displays The RMT annunciator is on when the Signal Generator is in the remote mode and after it has received its first Data message The TLK annunciator is on when the Signal Generator is currently addressed to talk the LSN annunciator is on when the Signal Generator is currently addressed to listen The SRQ annunciator is on when the Signal Generator is sending the Require Service message The MESSAGE key lights for the same conditions in remote as in local The message can be read in either remote
230. or is enabled to remote that is REN is set true and it receives the Local Lockout message it will switch to remote mode with local lockout the first time it is addressed to listen When in 3 40 HP 8673H local lockout the Signal Generator can be returned to local only by the controller using the Local or Clear Lockout Set Local messages by setting the LINE switch to STBY and back to ON or by removing the bus cable 3 39 Receiving the Clear Lockout Set Local Message The Clear Lockout Set Local message is the means by which the controller sets the Remote Enable REN bus control line false The Signal Generator returns to local mode full front panel control when it receives the Clear Lockout Set Local message When the Signal Generator goes to local mode the front panel RMT annunciator turns off 3 40 Receiving the Pass Control Message The Signal Generator does not respond to the Pass Control message because it does not have this controller capability 3 41 Sending the Require Service Message The Signal Generator sends a Require Service message if one or more of the following conditions exist and if it has been pre programmed to send the message by the Request Mask e Front Panel Key Pressed when the Signal Generator is in local mode and one of the front panel keys is pressed Front Panel Entry Complete when the Signal Generator is in local mode and is finished processing a front panel entry e Chan
231. or sweep stop frequency 2 Enter the desired frequency using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue entering the correct digits until the frequency displayed in the FREQUENCY MHz display is correct 3 Press the appropriate units key The frequency can be entered in GHz MHz or kHz Once the units key is pressed the displayed frequency will be adjusted to display MHz and the sweep stop frequency will be set The sweep stop frequency will continue to be displayed until the units key is released The actual frequency displayed after releasing the units key will usually not be the entered frequency If sweep mode is off the displayed frequency will indicate the frequency halfway between the start frequency and the new stop frequency If auto sweep is on the sweep will be reset and then continue using the new stop frequency If single sweep is on the sweep will be reset and the sweep will remain armed at the start frequency If manual sweep is on the sweep frequency will be reset to the start frequency To check the current sweep stop frequency press and hold the SWEEP FREQ STOP key The FREQUENCY MHz display will display the sweep stop frequency as long as the key is held When any sweep mode is turned off the CW frequency will be set to halfway between the start and stop frequencies equal to the sweep center frequency 3 143 Operation
232. ored in the Signal Generator s register 9 The most straight forward way to program the system controller is to use a loop to read 96 binary characters and store them in an array When the Signal Generator is addressed to listen the binary data can be returned to it in 96 byte strings When the Signal Generator detects the A it will expect the next 94 characters to be in the learn mode string A checksum is embedded in the string so that possible errors in the storage or transmission of the data will be detected and the input will be ignored Whenever data is being transferred between controller and Signal Generator it must do so in uninterrupted strings If a data string is broken or interrupted the data could be lost or offset and misinterpreted by the Signal Generator An offset of data bytes can persist through later data strings until the Signal Generator is eventually switched to standby then on again Special Function Learn Mode This mode is intended for servicing the Signal Generator It is similar in operation to the front panel learn mode After receiving an L2 program code Special Function Learn Mode and when addressed to talk the Signal Generator sends 2 ASCII characters and 9 followed by a string of 26 8 bit binary bytes This binary data can then be stored in the controller s memory The binary characters are directly related to the digital outputs of the Signal Generator s internal controller There is no
233. ormed For applications requiring fastest sweeps Auto Peak may be disabled However with Auto Peak disabled modulation performance and maximum output power may be degraded The time required for the Auto Peak operation is not included in the dwell time setting The automatic level control ALC bandwidth is increased when sweep mode is activated This provides fast response to switching transients when sweeping In addition activating sweep mode while amplitude modulating increases the useable AM bandwidth by more than 250 times See the amplitude modulation detailed Operating instructions for more information about AM bandwidth while in sweep mode The front panel annunciators are filtered in sweep mode to prevent false indications While sweeping the frequency changes cause a loss of phase lock and unleveled automatic level control during the frequency change To prevent constant flashing of the front panel annunciators the response is damped to indicate only major problems during a sweep The bits of the extended status byte are also buffered and should not be used to check individual Sweep points for phase lock and leveled RF output HP 8673H Operation Detailed Operating Instructions Manual Sweep Mode conta Programming The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The Example program is used to set the Signal Generator to the sweep mode specified by the variable Mode 10 SUB Sweep_set Err Mod
234. orrect voltage and fuse have been selected Verify that the line voltage selection card and the fuse are matched to the power source Refer to Figure 2 1 Line Voltage and Fuse Selection Fuses may be ordered under HP part numbers listed in the following table 100 120V 220 240V Fuse A3FL fae ee 2110 0002 2 6 Power Cabies BEFORE CONNECTING THIS INSTRU MENT the protective earth terminal of this instrument must be connected to the protective conductor of the mains power cable The mains plug shall only be inserted in socket outlets provided with a protective earth contact The protective action must not be negated by the use of an extension cord power cable without a protective conductor grounding This instrument is equipped with a three wire power cable When connected to an appropriate ac power receptacle this cable grounds the instrament cabinet 21 nema muwe HP 8673H Power Cables cont d The power cable plugs shipped with each instrument depend on the country of destination Refer to Figure 2 2 for the part numbers of power cables available 2 7 HP IB Address Selection In the Signal Generator the HP IB talk and listen addresses can be selected by an internal switch or bya front panel setting Refer to Table 2 1 fora listing of talk and listen addresses The address is factory set for a Talk address of S and a Listen address of 3 In binary this is 10011 in decimal this is 19
235. ould also be right justified when the units key is pressed The frequency could also have been entered as 12340 MHz or 12340000 kHz The only difference is the placement of the decimal point and the units terminator Pressing the MKR key and then MKR OFF will deactivate all of the markers 3 91 Operation HP 8673H Detailed Operating Instructions Example cont d Program Codes Comments 3 92 Marker Frequency Sweep conta Remote The programming string for setting a marker is composed of a marker identifier the frequency and a units terminator The sweep marker frequency can be programmed in units of GHz MHz kHz or Hz To program marker 3 to 12 34 GHz the possible program strings are M312 34GZ or M312340M2 or M312340000KZ or M312340000000HZ The alpha non numeric characters can be sent as upper or lower case or even mixed upper and lower case Marker Activation Codes Program Description Code All markers off Activate marker 1 Activate marker 2 Activate marker 3 Activate marker 4 Activate marker 5 AH markers off Activate marker 1 Activate marker 2 Activate marker 3 Activate marker 4 Activate marker 5 Setting Sweep Marker Deactivation Sweep Marker Frequency Sweep Marker Off MO Each marker that is activated adds a frequency point to the sweep If the marker frequency already exists in the sweep an additional frequency will be added to the sweep and will
236. output level is not within the range of the Signal Generator 3 115 Operation HP 8673H Detailed Operating Instructions Description Local Procedure Remote Procedure Example 3 116 Recall and Store Registers The Signal Generator has nine instrument state storage registers These registers allow the complete instrument state to be saved in non volatile memory A subsequent recall of the stored register will set the Signal Generator to the state that was saved All front panel settings including sweep and modulation are stored when one of the nine registers is used for instrument state storage Powering down the instrument will not destroy the setting of the nine state registers The registers may be cleared to the preset state with a special key sequence see comments Register 0 is the instrument preset register Recalling this register will set the instrument to a known state An alternate preset state is set by another special key sequence To store the current instrument state in one of the nine storage registers 1 Press the STO key shifted RCL to indicate that the current settings are about to be saved in one of the storage registers 2 Press a number corresponding to one of the nine storage registers Any number between 1 and 9 may be used as a storage register Once the key is pressed the instrument state is saved in that register To recall the instrument state from one of the storage registers 1 Pr
237. paragraph entitled Mechanical Options in Section 1 2 14 STORAGE AND SHIPMENT 2 15 Environment The instrument should be stored in a clean dry environment The following environmental limitations apply to both storage and shipment Temperature 55 to 75 C Humidity aeaaea ao e ARN lt 95 relative Altitude ooo cece 15 300 metres 50 000 feet 2 16 Packaging Preparation for Packaging Remove handles and or rack mount flanges before packaging instrument for shipping Tagging for Service If the instrument is being returned to Hewlett Packard for service please complete one of the blue repair tags located at the back of this manual and attach it to the instrument Original Packaging Containers and materials identical to those used in factory packaging are available through Hewlett Packard offices Mark the container FRAGILE to assure careful handling In any correspondence refer to the instrument by model number and full serial number Other Packaging The following general instructions should be used for re packaging with commercially available materials a Wrap the instrument in heavy paper or plastic if shipping to a Hewlett Packard office or service center complete one of the blue tags mentioned above and attach it to the instrument b Use a strong shipping container A double wall carton made of 2 4 MPa 350 psi test material is adequate c Use enough shock absorbing material 75 to 100 mm laye
238. play should read 6050 MHz 9 Initiate the desired sweep mode AUTO MANUAL or SINGLE by selecting the desired sweep mode on the Master unit Any number of slave units up to the limit of the HP IB can be controlled with a single Master unit To add another Slave unit connect the additional Signal Generator to the Master unit with an HP IB cable set the Slave units HP IB address to 40 and enter the desired sweep parameters When entering sweep step size or number of steps use identical values for the Master and Slave units If identical values are not entered the sweeps will not track identically resulting in increasing or decreasing offsets as the sweep progresses Adjusting the TUNE knob on the Slave unit will tune the sweep center frequency to a different value resulting in loss of the desired frequency offset between the Master and Slave units Operation HP 8673H Detailed Operating Instructions Comments cont d Error Messages 3 96 Master Slave Sweep cont d When in MANUAL mode the Master unit can be used to reset both units to the s weep start frequency To do so press the SINGLE key then press the MANUAL key on the Master unit The Master and Slave units will be reset to their respective start frequencies The sweep modes of the Master unit AUTO MANUAL and SINGLE are controlled by the Master s front panel The Slave unit s MANUAL and SINGLE keys will always be lit no matter which mode the Master unit i
239. plemental Characteristics For information on HP IB capabilities refer to the summary contained in Table 3 3 Message Reference Table 3 4 Local Operation Information covering front panel operation of the Signal Generator is given in the sections described below To quickly learn the operation of the instrument begin with Simplified Operation and Operator s Checks Once familiar with the general operation of the instrument use the Detailed Operating Instructions for more complete information about operating the Signal Generator Turn On Information Instructions relating to the Signal Generator s turn on procedure are presented in paragraphs 3 9 through 3 11 to acquaint the user with the general operation of the instrument The user should perform these procedures prior to using the Simplified Operating instructions or the Detailed Operating instructions Simplified Operation The instructions located on the inside of this fold provide a quick introduction to front panel operation o f the Signal Generator These instructions are designed to quickly acquaint the new user with basic operating procedures and therefore are not an exhaustive listing of all Signal Generator functions Additional operating information is given in paragraphs 3 12 through 3 16 Detailed Operating Instructions The Detailed Operating Instructions provide the complete operating reference for the Signal Generator user The instructions are organized alphabe
240. plitude signals For example to level a signal with an amplitude of 50 dBm after a signal path with losses of 30 dB the attenuation can be set to 10 dB range 10 dB to place the Signal Generator at an RF output level of only 20 dBm 3 64 HP 8673H Comments cont d Application Example Error Messages Operation Detailed Operating Instructions Diode Automatic Level Control conta The internal circuitry generates RF levels of 10 dBmand higher before introducing attenuation to increase the dynamic range of the Signal Generator When selecting the proper range for external leveling the lowest and highest gain loss should be calculated The range is then set 10 dB higher than the level required to keep the internally generated RF level near 10 dBm Using a range lower than 0 dB has the advantage of improving the source match and reducing the noise floor of the Signal Generator at the expense of reducing maximum available power The extemal ALC circuitry is used to adjust the Signal Generator s output level until the detected voltage at the external ALC input is correct If high harmonics or spurious signals are present in the signal that is being detected they will affect level flatness This is especially important when using external amplifiers and mixers within the signal path For example if the RF signal level is 10 dBm and the second harmonic is at 0 dBm the actual detected power will be 11 milliwatts 10 4 dBm ins
241. program the CW frequency the program code FR or CW is sent followed by the desired frequency and the units GZ MZ KZ or HZ The CW programming code also tums off sweep if any sweep mode is active when the program code is received by the Signal Generator Once a frequency is programmed the SOURCE SETTLED bit of the status byte can be monitored to determine when the frequency has settled Once this bit is set the NOT PHASE LOCKED bit in the extended status byte may be checked to ensure that the instrument is working correctly The NOT PHASE LOCKED bit is not valid until after the SOURCE SETTLED bit has been set Both the set CW frequency and the current RF output frequency can be read by the controller using the output active program code suffix or a special program code To read the CW frequency not the output frequency if the frequency was rounded send the program codes FROA and then read the frequency The Signal Generator will send the CW frequency in fundamental Hz units If the CW frequency is read as a string the format will be the program code CF followed by the CW frequency in Hz and then the units terminator Hz To read the current output frequency the program code OK is sent and then the current RF output frequency can be read The format is the same as the FROA method described above This method should not be used while sweeping as the frequency read will not be correct during sweep Note that the latter method indicates the
242. ps SS SS SP Preferred Program Code The Signal Generator digital sweep is composed of discrete frequencies that are produced sequentially The minimum step size is limited to the frequency resolution which is the minimum change in frequency that the Signal Generator can produce The number of steps is dependent on the frequency resolution and the sweep span The actual change in output frequency will not be uniform for some frequencies and may vary up to 2 kHz This is required to accommodate Sweep step sizes that are not exact multiples of the frequency resolution The Sweep steps averaged over several sweep points will be equal to the selected sweep step size An example of the averaging is defining a sweep step size of 7 kHz at a start frequency of 11 GHz The minimum tuning increment at 11 GHz is 2 kHz which means that the sweep step size can be 6 or 8 kHz for exact Step sizes To obtain a sweep step size of 7 kHz the Signal Generator will step by 8 kHz then 6 kHz and then repeat the sequence The average step size is 7 kHz even though the sweep does not execute exactly 7 kHz steps If the step size is reduced to 1 kHz the Signal Generator will step by 2 kHz and then 0 kHz for a 1 kHz average step size HP 8673H Comments cont d Programming Example Error Messages Operation Detailed Operating Instructions Steps Sweep cont d When the sweep frequency span is changed the sweep step size is recalculated by div
243. put Impedance 509 Output Level 0 to 3 5 V Pulse Width 80 ns to 2 ps Frequency Range 50 MHz to 7 GHz HP 8566B Frequency Span Division 1 kHz minimum Amplitude Range 0 to 70 dB Test Oscillator Level 0 to 3V into SOQ or 3002 HP 3335A or HP 8116A Range 10 kHz to 10 MHz l RHG Electronics Laboratory Inc 161 East Industry Court Deer Park NY 11729 Tel 516 242 1100 TWX 510 227 6083 HP 8447E Note HP 8447F is a dual amplifier and will satisfy both requirements HP 8116A or HP 80133 Pulse Generator Spectrum Analyzer 1 18 HF 5073H HISALHAUOR SECTION 2 INSTALLATION 2 1 INTRODUCTION This section provides the information needed to install the Signal Generator Included is information pertinent to initial inspection power requirements line voltage selection power cables interconnection environment instrument mounting storage and shipment 2 2 INITIAL INSPECTION To avoid hazardous electrical shock do not perform electrical tests when there are signs of shipping damage to any portion of the outer enclosure covers panels meters Inspect the shipping container for damage If the shipping container or cushioning material is damaged it should be kept until the contents of the shipment have been checked for completeness and the instrument has been checked mechanically and electrically The contents of the shipment should be as shown in Fig
244. put Lock Frequency Front Panel Learn Mode Output Request Mask Output Status Power Level RANGE and VERNIER PULSE OFF PULSE OFF PULSE NORM PULSE COMP RANGE Recall RCL Alternate Instrument Preset RANGE Down 10 dB RF OFF RFON Recall RCL RQS Mask Reset Sweep RANGE Up 10dB RF OFF RFON Slave Down STEP MANUAL Sweep STEP Shift Steps suffix Store STO Slave Up Service Function Test Interface Execute Trigger Meter LVL Meter AM Meter FM FREQ INCREMENT Up VERNIER SWEEP MODE OFF SWEEP MODE OFF AUTO Sweep MANUAL Sweep SINGLE Sweep SINGLE Sweep Arm Only SINGLE Sweep Arm and Begin Master Sweep Slave Sweep XFREQ Markers OFF Marker 1 Marker 2 Marker 3 Marker 4 Marker 5 FREQ display off FREQ display on Start of Front Panel Learn Mode Prefix for Request Mask Deferred Execution Mode Immediate Execution Mode Start of Special Function Learn Mode 3 43 Operation HP 8673H Table 3 7 Index of Detailed Operating Instructions Note The Detailed Operating Instructions are referenced to the front panel controls and are arranged in alphabetical order Function Subjects AUTOMATIC LEVEL CONTROL Diode Automatic Level Contro Internal Automatic Level Control Power Meter Automatic Level Control System Automatic Level Control Frequency CW Frequency Increment and Tuning MISCELLANEOUS CAPABILITIES Auto Peak Master Slave Sweep Messages Multiplier Mode Of
245. qual to the selected sweep step size An example of the averaging is defining a Sweep step size of 7 kHz at a start frequency of 11 GHz The minimum tuning increment at 11 GHz is 2 kHz This means that the sweep step size can be 6 kHz or 8 kHz for exact step sizes To obtain a sweep step size of 7 kHz the Signal Generator will step by 8 kHz and 6 kHz and then repeat the sequence The average Step size is 7 kHz even though the sweep does not execute exactly 7 kHz steps If the step size is reduced to 1 kHz the Signal Generator will step by 2 kHz and then 0 kHz for a 1 kHz average step size in the 2 kHz resolution frequency band Sweeps from a higher frequency to a lower frequency can be accomplished by setting the start frequency higher than the stop frequency This combination results in a negative frequency span as indicated when the frequency span is displayed Negative frequency spans can only be entered by setting the start frequency higher than the stop frequency The tuning controls will work as with a positive span but the remote program code IF will always produce a sweep step toward the stop frequency An Auto Peak operation is performed whenever the RE output frequency is more than 50 MHz from the frequency at which the last Auto Peak Operation was performed The Auto Peak operation optimizes the Signal Generator performance at the current frequency The Auto Peak operation produces small changes in the RF output level as the peaking is perf
246. quency is set If the status byte is not cleared the SOURCE SETTLED bit may have been set by a previous command the bit is latched until the status byte is read or cleared 500 SUB Settled 510 T_counter TIMEDATE In case no source settled 520 Stat SPOLL 719 Serial poll 530 IF TIMEDATE T_counter gt 1 THEN Done Default of 1 second 540 IF NOT BIT Stat 3 THEN GOTO 520 Wait for set bit 550 Done 560 SUBEND Source is settled or 1 second has passed Error The following message numbers may be displayed when setting the CW frequency Each Messages message is explained as it pertains to setting CW frequency For a more complete description of the messages see the MESSAGES detailed operating instructions 01 Entered frequency is not within the range of the Signal Generator 03 Invalid multiplier entry for system compatible instruments 90 Auto Peak malfunction This indicates that the instrument may require service 3 73 Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 74 Frequency Increment and Tuning The Signal Generator frequency can be tuned in any tuning increment that will result in a new frequency within its specified range The tuning increment is set with the FREQ INCR key and the numeric keypad All valid frequency increments may be remotely programmed or entered manually via a numeric keypad Tuning the Signal Generator frequency is accomplished using the FREQ INCREM
247. quired power HP 8673H Operation Detailed Operating Instructions Power Meter Automatic Level Control conta Comments cont d Application Examples Error Messages Using Signal Generator ranges of 10 to 90 dB add attenuation to the RF signal path These ranges are useful mainly when attempting to level low amplitude signals For example to level a signal with an amplitude of 50 dBm after a signal path with losses of 30 dB the attenuation can be set to 10 dB range 10 dB to place the Signal Generator at an RF output level of 10 dBm The internal circuitry generates RF levels of 10 dBm and higher before introducing attenuation to increase the dynamic range of the Signal Generator When selecting the proper range for external leveling the lowest and highest gain loss should be calculated The range is then set 10 dB higher than the level required to keep the internally generated RF level near 10 dBm The external ALC circuitry is used to adjust the Signal Generator s output level until the detected voltage at the external ALC input is correct If high harmonics or spurious signals are present in the signal that is being detected they will affect level flatness This is especially important when using external amplifiers and mixers within the signal path For example if the RF signal level is 10 dBm and the second harmonic is at 0 dBm the actual detected power will be 11 milliwatts instead of 10 milliwatts 10 dBm Fo
248. r STOP OFFSET Key Normal operation STOP Used as a prefix to the Data and Units keys to set the ending frequency of a sweep Pressing this key displays the present STOP value in the FREQUENCY MHz display for as long as the key is depressed Shifted function OFFSET Used as a prefix te the Data and Units keys Invokes the offset mode of frequency entry and display Frequency entries will be displayed as entered but the actual instrument output frequency will be the offset amount BELOW the entered and displayed frequency AF OFFSET Key Normal operation AF Used as a prefix to the Data and Units keys to set sweep span Pressing this key displays the present span value in the FREQUENCY MHz display for as long as the key is depressed Center frequency of the span is set with the FREQUENCY key Shifted function OFFSET Used as a prefix to the Data and Units keys Invokes the offset mode of frequency entry and display Frequency entries will be displayed as entered but the actual instrument output frequency will be the offset amount ABOVE the entered and displayed frequency 9 SEEE 6 MKR Key Enables previously selected marker frequencies when used as a prefix to Data keys 1 through 5 For example pressing MKR and 1 enables Marker 1 When used as prefix to the Data and Units keys it sets marker frequencies For example pressing MKR 1 6 and GHz sets the frequency of Marker 1 to 6 GHz The first digit pre
249. r 3 to 4 inches around all sides of the instru ment to provide firm cushion and prevent movement in the container Protect the front panel with cardboard d Seal the shipping container securely e Mark the shipping container FRAGILE to assure careful handling SIGNAL GROUND P O TWISTED PAIR WITH 11 P O TWISTED PAIR WITH 10 SHOULD BE GROUNDED P O TWISTED PAIR WITH 9 NEAR TERMINATION OF OTHER WIRE OF P O TWISTED PAIR WITH 8 TWISTED PAIR PIO TWISTED PAIR WITH 7 P O TWISTED PAIR WITH 6 Installation SHIELD CONNECT TO ATN GROUND SRO IFC NDAC NRFD DAV REN 0 DIO8 DIO DIO6 DIOS 1S0 METRIC THREAD mises NO A wen MICRO RIBBON SERIES 57 CONNECTOR Logic Levels The Hewlett Packard Interface Bus Logic Levels are TTL compatible i e the true 1 state is 0 0 Vde to 0 4 Vdc and the false 0 state is 2 5 Vde to 5 0 Vdc Programming and Output Data Format Refer to Section 3 Operation Mating Connector HP 1251 0293 Amphenol 57 30240 Mating Cables Available HP 10833A 1 metre 3 3 ft HP 10833B 2 metres 6 6 ft HP 10833C 4 metres 13 2 ft HP 10833D 0 5 metres 1 6 ft Cabling Restrictions 1 A Hewlett Packard Interface Bus system may contain no more than 2 metres 6 ft of connecting cable per instrument 2 The maximum cumulative length of connecting cable for any Hewlett Packard Interface Bus system is 20 0 metres 65 6 ft A3W18 HP IB Adapter HP part number
250. r a detected voltage of 1 volt for 10 dBm the detected signal will be at 1 1 volts for the 11 milliwatt signal This will cause a leveling error of about 0 83 dB Example 1 External ALC over the range of 0 to 10 dBm is required The RF signal path exhibits an insertion loss of 6 dB that varies 12 dB over the frequency range To control the output level over a 0 to 10 dBm range an amplifier capable of 16 dBm 10 dBm 4 dB 2 dB is required The range selected for this application depends mainly on the gain of the amplifier If we assume a gain of 10 dB the optimum Signal Generator range is 0 dB The overall signal path gain varies from 12 to 16 dBm To reduce the level to 10 dBm would require 10 dB of attenuation The range is set 10 dB above this requirement or 0 dB Example 2 The IF output of a mixer is to be leveled at 20 dBm The conversion loss of the mixer is 10 dB and varies 3 dB over the frequency range Using the Signal Generator as the RF source for the mixer the power meter is connected to the IF port of the mixer using a 10 dB directional coupler The attenuation of the signal path is 10 dB and varies 3 dB For an IF level of 20 dBm the RF port must be at a level of approximately 10 dBm The range selected for the Signal Generator would then be 10 since 0 dB attenuation would be required and the 10 dB range is one step above zero attenuation The following message may be displayed when programming the RF output l
251. r frequency Frequencies below 6 6 GHz can be set to the nearest 1 kHz All frequencies between 6 6 and 12 3 GHz can be set within 2 kHz of the desired value Frequencies between 12 3 and 18 0 GHz can be set within 3 kHz of the desired value However with careful selection of frequency the roundoff error can be reduced to 1 kHz When the sweep start and or stop frequency cannot be set exactly due to frequency resolution a random roundoff occurs To prevent this the remote program can perform a calculation to determine whether the frequency can be set exactly and adjust the desired frequency accordingly If the actual start and stop frequencies are critical setting the start and stop frequency instead of center frequency and delta frequency can be used for greater assurance that the start and stop frequencies are correct To determine whether a frequency can be set to a given value divide the desired frequency in kHz by two if it is between 6 6 and 12 3 GHz or by three if it is between 12 3 and 18 0 GHz If the result is a whole number no remainder the frequency can be set to the desired value For example 12 4 GHz divided by three it is between 12 3 and 18 0 GHz is 4133333 33 kHz Since the dividend is not a whole number this frequency cannot be set exactly The nearest frequencies that can be set are 12 399999 GHz 4 133333X3 and 12 400002 GHz 4 133334X3 Note that the roundoff error is only 1 kHz if 12 399999 GHz is programmed instea
252. remented or decremented in the same manner as the FREQ INCREMENT up and down keys The UP program code is equivalent to a single press of the FREQ INCREMENT up key DN is equivalent to a single press of the FREQ INCREMENT down key If a frequency increment UP will produce a frequency that is above the range of the instrument the frequency will not change and an error 02 will be issued to indicate that the frequency increment is out of range If a frequency decrement DN will produce a frequency that is below the range of the instrument the frequency will not change and an error 01 will be issued to indicate that the desired frequency is out of range To tune the CW frequency in 1 5 MHz steps Local 1 Press the FREQ INCR key 2 Key in 1 5 using the numeric keypad The FREQUENCY MHz display should show 1 5 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the MHz units key to finish the sequence The FREQUENCY MHz display will show the entered frequency increment until the units key is released The entry should now be right justified 4 Turn the TUNE knob clockwise or press the FREQ INCREMENT up key to increment the frequency in 1 5 MHz steps Tum the TUNE knob counter clockwise or press the FREQ INCREMENT down key to decrement the frequency in 1 5 MHz steps Note that an error is not indicated if an attempt is made to tune the frequency above or below the frequency range of
253. requencies Programming the RF output level can be done in one of two ways The RF output level can be programmed directly using the program code LE AP or PL The units terminator for the output level is dBm which corresponds to the program code DM The Signal Generator will also accept the program code DB as the terminator When programming the RF output level the VERNIER is set between 0 and 9 9 dBm and the RANGE is set accordingly The RF output level can also be programmed by programming the VERNIER and the RANGE separately The program code to set the RANGE is RA and the program code to set the VERNIER is VE The units terminator for both codes can be either DB or DM The output active program code suffix can be used to read the current values of the RANGE VERNIER or the RF output level directly To read the RANGE setting send the program codes RAOA and then read the RANGE setting The Signal Generator will send the RANGE in fundamental dBm units If the RANGE is read as a string the format will be the program code RA followed by the RANGE in dBm and then the units terminator DM dBm 3 113 Operation HP 8673H Detailed Operating Instructions Remote Procedure cont d Example Program Codes 3 114 Range Output Level conta In local mode the Signal Generator keeps track of the VERNIER setting to within 1 dB When switching to remote mode the local RF level setting is preserved This feature also allows th
254. requency Tuning Codes Program Function Code Increment CW center frequency by frequency increment by step size in MANUAL sweep mode Decrement CW center frequency by frequency increment by step size in MANUAL sweep mode MANUAL sweep mode only see MANUAL SWEEP Disable TUNE knob not active in remote or local mode Enable TUNE knob active in local mode only li HP 8673H Comments Operation Detailed Operating Instructions Frequency Increment and Tuning cont d Due to the use of frequency multiplication to generate frequencies above 6 6 GHz the minimum tuning increment is increased Frequencies below 6 6 GHz can be tuned with a minimum step size of 1 kHz For frequencies between 6 6 and 12 3 GHz the minimum tuning resolution is 2 kHz Frequencies between 12 3 and 18 0 GHz can be tuned with a minimum resolution of 3 kHz When setting a frequency increment the entered value can be as low as 1 kHz even though a 1 kHz tuning resolution is not possible for all output frequencies If a frequency increment is entered that is not a multiple of the specified frequency resolution for the RF output frequency the two nearest tuning resolutions will be used in combination so that the overall affect will be the desired tuning resolution For example if a frequency increment of 7 kHz is selected and the output frequency is set to 11 GHz tuning down one step will change the output frequency by 6 kHz for one step and then 8 k
255. ription Code Code Store Instrument State RCO Instrument Preset Recall Instrument State Instrument Preset Recall Instrument State Alternate Preset The nine storage registers can be cleared using a special front panel key sequence This feature is useful in high security applications to destroy any instrument settings that might compromise the security To clear the storage registers press the LVL key near the front panel meter and the FM 3 MHz deviation range keys at the same time A successful initialization of all of the storage registers can be confirmed by an instrument preset when the two keys are pressed All of the registers will be initialized to the preset state Storing a register in remote mode will store the remote VERNIER setting If this register is recalled in local mode the remote VERNIER setting will be selected and local VERNIER control will be disabled The local VERNIER setting is stored when a register is stored in local mode Recalling this register in remote mode will use the stored local mode setting as the remote VERNIER setting There are two preset states that can be selected in remote mode or from the front panel The first preset state is selected by recalling register zero in local or remote mode or sending the program code IP in remote mode The register 0 preset conditions are given below 3 117 Operation HP 8673H Detailed Operating Instructions Comments cont d Error Messages 3 118
256. rmat is Steps When the controller sends SPOA the Signal Generator returns with the string SP Step Size HZ SP Number of Steps SS LF and EOI The Signal Generator may output a program code that differs from the code sent to it by the controller For example the Signal Generator responds with the program code CF center frequency when sent FR frequency and MK marker when sent M1 M2 M3 M4 or M5 Markers 1 through 5 Output Couple After receiving the program code OC Output Couple and when addressed to talk the Signal Generator sends a data string that gives the current numeric values for the following parameters in the order listed START Center Frequency DWELL LF and EOI No program codes prefix the numeric values Hz is the implied terminator for start and center frequency milliseconds is the implied terminator for dwell time Output Lock Frequency This function causes the Signal Generator to output the value of its tuned frequency After receiving the program code OK and when addressed to talk the Signal Generator sends the value of the frequency at which it is currently phase locked The data output from the Signal Generator is in the following format FR Numeric Value HZ LF and EOT Test Interface Function This function allows testing of the HP IB interface After receiving the program code TI followed by an 8 bit byte representing one or more data lines see table beiow and when addressed
257. rnier Output Level conta Programming 240 I Example 250 IF Expected gt O THEN Check for unleveled cont d 260 OUTPUT 719 USING 2A 0 Get extended status byte 270 ENTER 719 USING B B V Extended i 280 IF BIT Extended 6 THEN 290 Err 1 300 DISP WARNING The Signal Generator RF output is not leveled 310 END IF 320 ENDIF 340 SUBEND Error The following message may be displayed when setting the RF output level Each message is Messages displayed as it pertains to setting the RF output level For a more complete description of the messages see the MESSAGES detailed operating instructions 24 The programmed RF output level is not within the range of the Signal Generator 3 154
258. rogram is used to set the marker specified by Marker to the frequency specified by the variable Expected The marker must be between and 5 and the marker frequency can be any valid Signal Generator frequency 10 SUB Marker_set Err Marker Expected 20 IF Marker lt 1 or Marker gt 5 then 30 Erre 1 40 DISP ERROR Marker number not between 1 and 5 50 SUBEXIT 60 ENDIF 7m 80 OUTPUT 719 USING 2A MG Clear any old messages 90 ENTER 719 USING 2A Message 100 110 OUTPUT 719 USING 2A 5D DDD 2A M amp VAL Marker Expected MZ 120 i 130 OUTPUT 719 USING 2A MG Check for errors 140 ENTER 719 USING 2A Message 150 SELECT VAL Message 160 CASE 4 170 Err 1 180 DISP ERROR Marker frequency is out of range 190 CASE ELSE 200 Err 0 210 END SELECT 220 230 SUBEND The following messages may be displayed when setting the sweep markers Each message is explained as it pertains to setting sweep markers For a more complete description of the messages see the MESSAGES detailed operating instructions 01 The entered frequency is not within the range of the Signal Generator 09 The entered marker number is not between 1 and 5 Operation HP 8673H Detailed Operating Instructions Description Local Procedure 3 94 Master Slave Sweep Master Slave Sweep enables two Signal Generators to track each other while sweeping The output frequencies of the Signal Generators can be identical or off
259. rogramming Example cont d Error Messages Operation Detailed Operating Instructions Start Frequency Sweep cont d The following program can be called to wait for a source settled indication from the Signal Generator The program will wait a maximum of 1 second before assuming the SOURCE SETTLED bit is not going to be set The status byte must be cleared with the CS program code before the frequency is set If the status byte is not cleared the SOURCE SETTLED bit may have been set by a previous command the bit is latched until the status byte is read or cleared 500 510 520 530 540 550 560 SUB Settled T_counter TIMEDATE In case no source settled Stat SPOLL 719 Serial poll IF TIMEDATE T_counter gt 1 THEN Done Default of 1 second IF NOT BIT Stat 3 THEN GOTO 520 Wait for set bit Done SUBEND Source is settled or 1 second has passed The following message numbers may be displayed when setting the sweep start frequency Each message is explained as it pertains to setting sweep start frequency For a more complete description of the messages see the MESSAGES detailed operating instructions 01 10 11 12 13 90 Entered frequency is not within the range of the Signal Generator The sweep start frequency has been set equal to the stop frequency No sweep will occur when a sweep mode is selected Indicates that the current sweep start frequency is below the range of the Signal Generator Th
260. rounded frequency while the former does not To set the frequency to 11 232 334 MHz Local 1 Press the FREQUENCY key 2 Key in 11 232 334 using the numeric keypad The FREQUENCY MHz display should show 11 232 334 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the MHz units key to finish the sequence The FREQUENCY MHz display should now show the entered frequency The FREQUENCY MHz display should now be right justified The frequency could also have been entered as 11 232334 GHz or 11232334 kHz The only difference is the placement of the decimal point and the units key pressed after the frequency has been entered using the numeric keypad Operation HP 8673H Detailed Operating Instructions Example cont d Program Codes Comments 3 70 Frequency CW conta Remote The programming string for setting the CW frequency is composed of a program code numeric data and the units terminator The frequency may be programmed in units of GHz MHz kHz or Hz To program the Signal Generator to 11 232 334 MHz the possible program strings are FR11 232334GZ or FR11232 334MZ or FR11232334KZ or FR11232334000HZ In addition the program code could be CF or CW instead of FR The alpha characters can be sent as upper or lower case or even mixed upper and lower case The Signal Generator output frequency is valid once the SOURCE SETTLED bit of the status byte i
261. rs the response is damped to indicate only major problems during a sweep The bits of the extended status byte are also buffered and should not be used to check individual sweep points for phase lock and leveled RF output The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The following program is us d to set the Signal Generator to the sweep mode specified by the variable Mode 10 SUB Sweep_set Err Mode 20 OUTPUT 719 USING 2A MG f Read message from 8673 30 ENTER 719 USING 2A Message ito clear any old messages 40 SELECT Mode 50 CASE AUTO AUTOMATIC 60 Code W2 l Auto sweep mode 70 CASE MANUAL 80 Code W3 90 CASE SINGLE ONCE 100 Code W6 Arm and begin single 110 CASE ELSE 120 DISP WARNING Invalid sweep mode specified 130 Erra 1 140 SUBEXIT 150 END SELECT 160 170 OUTPUT 719 USING 2A Code 180 190 SUBEND End of subroutine HP 8673H Operation Detailed Operating Instructions Auto Sweep Mode conta Error The following message numbers may b e displayed when activating automatic sweep mode Messages Each message is explained as it pertains to activating automatic sweep mode For a more complete description of the messages see the MESSAGES detailed operating instructions 10 The start and stop frequency are set to the same value No sweep will be generated 11 The current sweep span is set such that the start frequency would be below th
262. rt Frequency MZ KZ HZ Preferred Program Code Due to the use of frequency multiplication to generate frequencies above 6 6 GHz the frequency sometimes cannot be set precisely to a desired value Frequencies below 6 6 GHz can be set to the nearest 1 kHz All frequencies between 6 6 and 12 3 GHz can be set within 2 kHz of the desired value Frequencies between 12 3 and 18 0 GHz can be set within 3 kHz of the desired value However with careful selection of frequency the roundoff error can be reduced to 1 kHz When the Signal Generator is programmed to a frequency that cannot be set exactly due to frequency resolution a random roundoff occurs To prevent this the remote program should perform a calculation to determine whether the frequency can be set exactly and adjust the desired frequency accordingly To determine whether a frequency can be set to a given value divide the desired frequency in kHz by two if it is between 6 6 and 12 3 GHz or by three if it is between 12 3 and 18 0 GHz If the result is a whole number no remainder the frequency can be set to the desired value For example 12 4 GHz divided by three it is between 12 3 and 18 0 GHz is 4133333 33 kHz Since the dividend is not a whole number this frequency cannot be set exactly The nearest frequencies that can be set are 12 399999 GHz 4 133333X3 and 12 400002 GHz 4 133334X3 Note that the roundoff error is only 1 kHz if 12 399999 GHz is programmed instead of 12
263. s activated The calibration in the next step will eliminate this indication 4 Adjust the front panel CAL control until the UNLEVELED annunciator is extinguished Set the VERNIER for a 0 dBm indication on the level meter and then adjust the CAL control until the power meter reads 10 dBm 3 63 Operation HP 8673H Detailed Operating Instructions Diode Automatic Level Control conta Example 5 The output level can now be set by adjusting the VERNIER for the desired output level as cont d read on the level meter Setting the range to 0 dB will reduce the output level by 10 dB However setting the range lower than 0 dB will not change the output level until the ALC goes unleveled due to insufficient output power to overcome the additional loss in the RF signal path Remote 1 Perform the above steps 1 to 4 to calibrate the extemal ALC circuitry 2 Set the output level remotely by programming vernier settings between 10 and 0 dBm Changing the range will have the same affects as described in step 5 above Program Description Code External Diode Leveling Mode Comments Using external diode leveling mode has the advantages of fast response time with a relatively simple leveling setup The disadvantages of diode leveling are the limited dynamic range of the square law region and the absence of temperature compensation 23 dB of dynamic range is typically available using the Signal Generator s 0 and 10 dB ranges In addition ampli
264. s armed with the program code W4 or WS Once the sweepis armed itcanbe executed with the program code W4 A single sweep can be armed and executed with the program code W6 The controller can monitor the SWEEP DONE bit of the extended status byte to determine when the sweep is finished The bit will be set when the stop frequency is reached and will not be reset until it is read or the status byte is cleared The output couple program code OC can be used to read the start frequency center frequency and dwell time in that order The three values are not prefixed by program codes and the frequencies are sent in Hz while the dwell time is sent in units of seconds To perform a single sweep from 8 to 10 GHz Local 1 Set the start frequency to 8 GHz and the stop frequency to 10 GHz 2 Press the SINGLE SWEEP MODE key to arm the single sweep The key indicator will light to indicate that single sweep mode has been selected 3 Press the SINGLE SWEEP MODE key again to execute the sweep Once the sweep is finished the single sweep will be rearmed in preparation for another sweep Remote The programming string to perform a single sweep is W6 The alpha character W can be sent as upper or lower case The Sweep can be armed and then executed later using the W4 or W5 program codes followed by a W4 program code when the sweep is to be executed Using the W5 program code always ensures that a single sweep is armed and does not execute immediat
265. s byte is not checked the program should wait at least the frequency switching speed time before assuming the output valid For controllers using buffered output an additional wait is required so that the RF output is not used until at least the specified frequency switching time elapses after the Signal Generator has received the program string If the status byte is to be used to monitor settling the program string that sets the frequency should be prefaced with the program code CS This will clear any previous setting of the SOURCE SETTLED bit to avoid an incorrect indication For frequency changes greater than 50 MHz an Auto Peak operation is performed by the Signal Generator The Auto Peak operation optimizes the Signal Generator performance at the set frequency The Auto Peak operation produces small changes in the RF output level as the peaking is performed In some cases the Auto Peak may require longer than the frequency switching time specification For applications requiring fastest switching speed Auto Peak may be disabled However with Auto Peak disabled modulation performance and maximum output power may be degraded The SOURCE SETTLED bit of the status byte is set when the Auto Peak operation is completed However when sending several program codes in the same data string the SOURCE SETTLED bit may be set by one of the other codes For maximum assurance that the Auto Peak is finished an Auto Peak should be performed just before the
266. s in the RANGE dB display Holding the key down will continue stepping the RANGE until the key is released The RANGE setting represents the maximum level available using that range The VERNIER control will allow setting output levels from 10 dB below to 3 dB above the RANGE There is a slight overlap of output level settings due to the 13 dB range of the VERNIER control For best results the VERNIER setting should be within the range of 10 to 0 dBm VERNIER settings from 0 to 3 dBm are available for observing a continuous range up to 3 dB above the RANGE setting without changing the RANGE setting 2 Adjust the VERNIER control until the sum of the RANGE and the level meter reading equal the desired RF output level The VERNIER can be used to vary the output level continuously about the set level or the RANGE up or down key can be used to step the output level in 10 dB steps If the UNLEVELED annunciator lights for high output level settings the level meter will indicate maximum available output power This should only occur when output levels above the specified maximum leveled power are set For example if the RF output level is set to 13 dBm and the level meter reads 4 dBm with the UNLEVELED annunciator lighted only 6 dBm of output power is available at that frequency The Signal Generator accepts any RF output level between 101 9 and 13 dBm RF output levels above the specified maximum leveled power may not be available at all f
267. s internal circuitry for leveling the output power at the front panel RF OUTPUT connector 6 DIODE SYS Key Normal operation Diode Selects external mode for leveling power using an external diode detector The output of the diode is connected to the Signal Generator s EXT ALC IN connector Shifted function SYS Selects the system leveling mode RF output power is leveled externally using a feedback voltage proportional to the system output power in volts per dB A system is the Signal Generator with an external amplifier multiplier etc The reference voltage must be 0 Vdc at 0 dBm system output and change 30 mV per dB This voltage is connected to the EXT ALC IN connector When SYS is selected both the INTERNAL and DIODE keys will light HP 8673H pwr MTR Key Selects external leveling mode for leveling power using an external power meter The recorder output of the power meter is connected to the EXT ALC IN connector Mechanical Meter Zero Sets meter suspension so that the meter indicates zero when power is removed from the Signal Generator and the Signal Generator is in its normal operating position OUTPUT LEVEL RANGE Keys age and r Selects the RF output level range in 10 dB steps from 90 to 10 dB The selected range is displayed in the RANGE dBm display OUTPUT LEVEL VERNIER Adjusts the RF output level over the range of 10 to 3 dBm relative to the LVL scale as read on the meter C9 C
268. s of the sweep width The output impedance is nominally 100 ohms The TONE MKR connector provides a 5 kHz signal when an active marker frequency is generated This signal can be connected to the AM IN connector on the front panel to provide AM markers on the external display Nominal impedance of the TONE MKR is 600 ohms The BLANKING MARKER output provides a 5 volt signal at the beginning of each frequency change for blanking an external display The blanking function is used to eliminate the display of switching transients Once the frequency has settled the signal returns to 0 volts unless the new frequency is an active marker frequency If the frequency is an active marker frequency the signal is set to 5 volts to provide a Z axis input for intensifying the display at the marker sweep point The PENLIFT connector provides control for an external X Y recorder and is only active during single sweep mode A TTL logic high is used to raise the pen and a TTL logic low is used to lower the pen The pen is only lowered in single sweep and there is a 100 millisecond sweep delay for the pen to raise or lower To set the Signal Generator for manual sweep mode 1 Set the desired sweep parameters The tuning controls will change the current sweep frequency by the sweep step size and not by the current frequency increment 2 Press the MANUAL SWEEP MODE key to activate manual sweep mode The key indicator will light and the frequency will be set to t
269. s operating in When using Master Slave sweep the 10 MHz frequency reference should be supplied by only one instrument This will improve the accuracy of the sweep and maintain phase coherent signals during the sweep The following messages may be displayed when using Master Slave sweep 01 Entered frequency is not within the range of the Signal Generator 03 Invalid multiplier entry for system compatible instruments See paragraph 3 2 System Compatibility for more information about system compatibility 10 The sweep start frequency has been set equal to the stop frequency No sweep will occur when a sweep mode is selected 11 Indicates that the current sweep start frequency is below the range of the Signal Generator This error may be displayed when the SWEEP FREQ START key is pressed if tuning the instrument placed the sweep start frequency below the frequency range of the Signal Generator 12 Indicates that the current sweep stop frequency is above the frequency range of the Signal Generator This error may be displayed when the SWEEP FREQ START key is pressed if tuning the instrument placed the sweep stop frequency above the frequency range of the Signal Generator 13 Number of steps were adjusted to give an even step size This ensures that the full sweep span is covered by adjusting the number of steps For example if the number of steps is set to 100 and the stop frequency is 11000 010 MHz setting the start frequency to 11 GHz
270. s set see comments Program Function Applicable Code Units CF GZ cw CW Frequency MZ FR KZ HZ Preferred Program Code Due to the use of frequency multiplication to generate frequencies above 6 6 GHz the frequency sometimes cannot be set precisely to a desired value Frequencies below 6 6 GHz can be set to the nearest 1 kHz All frequencies between 6 6 and 12 3 GHz can be set within 2 kHz of the desired value Frequencies between 12 3 and 18 0 GHz can beset within 3 kHz of the desired value However with careful selection of frequency the roundoff error can be reduced to 1 kHz When the Signal Generator is programmed to a frequency that cannot be set exactly due to frequency resolution a random roundoff occurs To prevent this the remote program should perform a calculation to determine whether the frequency can be set exactly and adjust the desired frequency accordingly To determine whether a frequency can be set to a given value divide the desired frequency in kHz by two if it is between 6 6 and 12 3 GHz or by three if it is between 12 3 and 18 0 GHz If the result is a whole number no remainder the frequency can be set to the desired value For example 12 4 GHz divided by three it is between 12 3 and 18 0 GHz is 4133333 33 kHz Since the dividend is not a whole number this frequency cannot be set exactly The nearest frequencies that can be set are 12 399999 GHz 4 133333X3 and 12 400002 GHz 4 133334X
271. s valid and the program may continue If the frequency is changed and the status byte is not checked the program should wait at least the frequency switching speed time specification before assuming the output valid For controllers with buffered output capability an additional wait is required to ensure that the frequency switching time plus the time required for the Signal Generator to receive the program string has elapsed before assuming the RF output is valid Operation HP 8673H Detailed Operating Instructions Comments cont d Programming Example Frequency Increment and Tuning conta If the status byte is to be used to monitor settling the program string that changes the frequency should start with the program code CS This will clear any previous setting of the SOURCE SETTLED bit to avoid an incorrect indication For frequency changes greater than 50 MHz an Auto Peak operation is performed by the Signal Generator The Auto Peak operation optimizes the Signal Generator performance at the set frequency The Auto Peak operation produces small changes in the RF output level as the peaking is performed In some cases the Auto Peak operation may require longer than the frequency switching time specification For applications requiring fastest switching speed Auto Peak may be disabled However with Auto Peak disabled modulation performance and maximum output power may be degraded The SOURCE SETTLED bit of the status byte is se
272. sages 40 OUTPUT 719 USING 2A 5D DDD 2A SP Expected MZ Set size 50 OUTPUT 719 USING 2A MG Get any error message 60 ENTER 719 USING 2A Message 70 SELECT VAL Message 80 CASE 1 90 Erret 100 DISP WARNING Sweep step size is out of range 110 CASE ELSE 120 Err 0 130 END SELECT 140 150 SUBEND The following message numbers may be displayed when setting the s weep step size Each message is explained as it pertains to setting sweep step size For a more complete description of the messages see the MESSAGES detailed operating instructions OS The entered sweep step size is not within the capability of the Signal Generator 14 The step size is too small for the current frequency span The entry is saved in anticipation that a new frequency span is going to be entered The frequency span divided by the entered frequency step size must be less than 9999 If the span is not changed the step size will be adjusted to produce an integer number of steps between 1 and 9999 15 The entered step size is larger than the currently defined frequency span The entry is saved in anticipation that the frequency span will be changed If the span is not changed the step size is set to equal to the span 1 step HP 8673H Description Local Procedure Operation Detailed Operating Instructions Stop Frequency Sweep The sweep stop frequency determines where the Signal Generator will end a sweep in each of the three sw
273. second time to execute a single sweep If SINGLE is pressed during the sweep the in progress sweep stops and is re armed The Slave unit will enter Slave mode when sweep is selected on the Master unit When the Signal Generator is in Slave mode the MANUAL and SINGLE indicators will be illuminated Master Slave sweep mode cannot be remotely programmed because the Master unit is acting a s a limited HP IB controller To operate Master Slave sweep with an offset of 50 MHz 1 Interconnect the two Signal Generators using an HP IB cable 2 Press RCL 0 on both Signal Generators 3 Designate one Signal Generator as the master unit by setting the HP IB address to 50 When the HP IB address is set to 50 the TLK annunciator on the front panel will light 4 Designate the second Signal Generator as the Slave unit by setting the HP IB address to 40 When the HP IB address is set to 40 the LSN annunciator on the front panel will light 5 On both instruments set SWEEP START to 6000 MHz and SWEEP STOP to 12000 MHz 6 On both instruments set the number of sweep steps to 100 This corresponds to a sweep step size of 60 MHz 7 On the Slave unit select a 50 MHz offset as follows press the FREQ INCR key and then key in 50 MHz Press FREQ INCREMENT key This changes the center frequency of the slave unit from 9 000 GHz to 9 050 GHz 8 Press and hold the SWEEP START key on the Slave unit Check the display for a 50 MHz offset The dis
274. see comments The format of the remote programming follows the front panel key sequence To program the sweep center frequency the program code CF is sent followed by the desired frequency and the units GZ MZ KZ or HZ The sweep center frequency can be read by the controller using the output active program code suffix To read the center frequency the program codes CFOA are sent and then the frequency is read The Signal Generator will send the frequency in fundamental Hz units If the frequency is read as a string the format will be the program code CF followed by the center frequency in Hz and then the units terminator Hz To set the sweep center frequency to 11 232 334 MHz Local 1 Press the FREQUENCY key 2 Key in 11232 334 using the numeric keypad The FREQUENCY MHz display should show 11232 334 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the MHz units key to finish the sequence The FREQUENCY MHz display should now show the entered frequency until the units key is released The frequency display should now be right justified The frequency could also have been entered as 11 232334 GHz or 11232334 kHz The only difference is the placement of the decimal point and the units key pressed after the frequency has been entered using the numeric keypad Remote The programming string for setting the sweep center frequency is composed of a program code numeric
275. set by a fixed amount The Master Signal Generator controls stepping the the sweep of the Slave In Master Slave mode two Signal Generators are interconnected through the Hewlett Packard Interface Bus HP IB The Master unit is set to HP IB address 50 and the Slave is set to HP IB address 40 The sweep start and stop frequencies are set to identical frequencies on both the master and slave instruments Desired offset is then entered on the Slave unit by adjusting the sweep center frequency The Master unit is swept using any of the three sweep modes The Slave unit will track the Master unit offset in frequency by the difference in sweep center frequencies To set two Signal Generators to Master Slave sweep mode 1 Interconnect the two Signal Generators using an HP IB cable 2 Press RCL 0 on both units 3 Designate one Signal Generator as the Master unit by setting the HP IB address to 50 The HP IB address can be set from the front panel by keying in 50 pressing the STO key then pressing the LOCAL key When the HP IB address is set to 50 the TLK annunciator on the front panel will light to indicate that the Signal Generator has entered the talk only mode 4 Designate the second Signal Generator as the Slave unit by setting the HP IB address to 40 When the HP IB address is set to 40 the LSN annunciator on the front panel will light 5 On both instruments set SWEEP START and SWEEP STOP frequencies to the desired Master sweep values
276. shoot and Ringing Test Setup 4 12 4 24 Risetime Overshoot and Ringing 4 25 Measurement ssesccsssrecrerneereesrensesseenevaeees 4 26 Pulse Peak Accuracy Measurement 4 27 AM Accuracy Test Setup 4 28 External FM Accuracy and Meter Accuracy 4 29 Test Setup scestacsconcusaatiedsiavevibeancvsvenseenes osc 4 30 Frequency Range and Resolution Test Setup 4 31 Intemal Time Base Aging Rate Test Setup 4 32 Frequency Switching Time Test Setup 4 33 Frequency Switching Waveform 4 34 Frequency Switching Time Measurement 4 35 Wavelonine aptata Eear DEAR ria AR TAAN 4 34 4 36 Amplitude Recovery Switching Waveform 4 36 Amplitude Recovery Measurement Waveform 4 38 4 37 TABLES Page Table Specifications 3 4 Supplemental Characteristics 3 5 Recommended Test Equipment cceesceesseveee 1 14 3 6 Abbreviated Performance Test Recommended Test 3 7 EPE taa N OA FN ee Fehe 1 17 3 8 Allowable HP IB Address Codes 4 1 Operating Characteristics 4 2 AUX Connector Functions 4 3 4 4 Message Reference Table Page Single Sideband Phase Noise Test Setup Harmonics Subharmonics and Multiples TSSt SOtup Sensa E is 4 44 Non harmonically Related Spurious Test Setup 4 46 Power Line Related Spurious Signals in TOT EE EEEE EEE A E 4 49 Output Level and Flatness Test Setup 4 51 Absolute Level Accuracy Test Setup n 4 55 Output Level Switching Time Test Setup 4
277. solute Level Accuracy Tests Output Level Switching Time Test Puise On Off Ratio Test Pulse Rise Fall Time and Overshoot Test Pulse Peak Level Accuracy Test AM Bandwidth AM Accuracy Tests Incidental FM FM Frequency Response External FM Accuracy and Meter Accuracy Introduction Incidental AM a a Wel bit aE ad nen ILLUSTRATIONS Figure Page Figure 1 1 HP 8673H Accessories Supplied and 2 5 AUX Interface Connector Options 907 908 and 909 3 1 Front Panel Features 1 2 Special Interconnect Cable 3 2 Displays and Status Annunciators 2 1 Line Voltage and Fuse Selection 3 3 Output Level Features n se 2 2 Power Cable and Mains Plug Part Numbers 2 2 3 4 Frequency Control Features and LINE Switch 2 3 HP IB Address Switch Factory Settings 2 3 3 5 Sweep Features and LOCAL Key eseesseeseoee 2 4 Hewlett Packard Interface Bus Connection 2 5 3 6 Modulation Features sssscsessseseeeseeesneeeeee iv HP 8673H 4 10 4 11 4 12 4 13 4 14 4 15 4 16 Contents ILLUSTRATIONS cont d Page Figure Rear Panel Features o ESAE 4 17 AM Functional Check Setup 4 18 FM Functional Check Setup Pulse Modulation Functional Check Setup 4 19 Status Byte Information 4 20 Frequency Range and Resolution Test Setup Output Level and Flatness Test Setup 4 21 Level Accuracy Test Setup 4 22 On Off Ratio Test Setup 4 23 Rise Time Over
278. solute frequency The output couple OC program code can be used to read the start frequency center frequency and dwell time in that order The values are not prefixed by program codes and the frequencies are sent in Hz while the dwell time is sent in seconds To sweep from 8 to 10 GHz in manual sweep mode Local 1 Set the start frequency to 8 GHz and the stop frequency to 10 GHz 2 Press the MANUAL SWEEP MODE key to activate manual sweep The key indicator will light to indicate manual sweep is active Remote The programming string to set manual sweep is W3 The alpha character W can be sent as upper or lower case Program Description Code W3 Manual Sweep Mode IF Increment Frequency Sweep The Signal Generator digital sweep is composed of discrete frequencies that are produced sequentially The minimum step size is limited to the minimum change in frequency that the Signal Generator can produce which is defined as the frequency resolution The number of steps is dependent on the frequency resolution and the frequency span Operation HP 8673H Detailed Operating Instructions Comments cont d Manual Sweep Mode conta The actual change in output frequency during a sweep will not be uniform for some frequency bands and may vary up to 2 kHz This is required to accommodate sweep step sizes that are not exact multiples of the frequency resolution The Sweep steps averaged over several sweep points will be e
279. splay should read 12 Require Service Message Note Operator s Response Note Operator s Response This check determines if the Signal Generator can issue the Require Service message set the SRQ bus control line true This check can be performed in either local or remote mode Description Series 200 300 HP 85B BASIC Send a Data message to set the RQS OUTPUT 719 USING OUTPUT 719 USING Mask to 32 2A B 1 32 2A BY 1 32 Send a Data message containing an OUTPUT 719 FR35GZ OUTPUT 719 FR35GZ invalid frequency This causes a Require Service message to be sent Check that the SRQ annunciator is on In the next step a short program is required if series 200 300 is the controller Read the binary status of the controller s 10 V 0 STATUS 7 2 V HP IB interface and store the data in 20 STATUS 7 7 V variable V in this step 7 is the interface s select code Display the value of the SRQ bit in 30 DISP SRQ DISP SRQ BIT V 6 this step 10 is the SRQ bit for the BIT V 10 series 200 300 and 5 is the SRQ bit for the HP 85B numbered from 0 40 END Check that the SRQ value is 1 indicating the Signal Generator issued the Require Service message 3 29 Operation gt HP 8673H OPERATOR S CHECKS HP IB Functional Checks cont d Status Bit Message Note Operator s Response Operator s Response 3 30 This check determines whether or not the Signal Genera
280. ss the FM key near the Signal Generator s front panel meter to set the meter to FM mode HP 8673H Example cont d Program Codes Comments Programming Example Operation Detailed Operating Instructions Frequency Modulation conta 2 Set the external oscillator to 10 kHz and adjust the amplitude to zero volts 3 Connect the external oscillator to the Signal Generator s FM IN connector Adjust the external oscillator amplitude until the middle scale 0 to 1 indicates 100 kHz deviation The required external oscillator amplitude will be approximately 1 volt peak or 0 707 volts ms Remote The programming string for setting the 100 kHz FM range is D3 The amplitude and frequency of the modulating signal must be set by programming the external modulating signal source The alpha character D can be sent as upper or lower case FM Off FM Off FM 0 03 MHz Range FM 0 1 MHz Range FM 0 3 MHz Range FM 1 MHz Range FM 3 MHz Range FM 10 MHz Range An Auto Peak operation occurs any time Auto Peak is enabled and an FM range is changed to maintain optimum operation With FM selected an Auto Peak operation does not turn off Auto Peak but instead sets the FM range to 0 03 MHz during the Auto Peak operation FM meter accuracy is specified for 100 kHz rates only To determine the meter accuracy at other modulation rates the FM frequency response specification is added to the meter accuracy The FM frequency response specificatio
281. ssage is explained as it pertains to activating single sweep mode For a more complete description of the messages see the MESSAGES detailed operating instructions 10 11 90 3 124 The start and stop frequency are set to the same value No sweep will be generated The current sweep span is set such that the start frequency would be below the frequency range of the instrument The sweep will begin at the lowest sweep point that is within the range of the Signal Generator All sweep points will be allotted but the frequency will not change until the sweep is within the frequency range of the Signal Generator The current sweep span is set such that the stop frequency would be above the frequency range of the instrument The sweep will end at the highest sweep point that is within the frequency range of the Signal Generator All sweep points will be allotted but the last sweep points will all be at the highest valid frequency Auto Peak malfunction This indicates that the instrument may require service HP 8673H Description Local Procedure Operation Detailed Operating Instructions Start Frequency Sweep The sweep start frequency determines where the Signal Generator will begin a sweep in each of the three sweep modes The sweep frequency limits are determined by setting either the start and stop frequency or the center frequency and frequency span Setting start and stop frequency will begin the sweep at the start frequen
282. ssed after the MKR key is always the marker number Pressing the MKR key displays all currently enabled marker numbers within the set sweep range in the FREQUENCY MHz display Pressing the MKR key and a Data key displays the present frequency of the requested marker SWEEP MODE OFF Key Disables all sweep modes auto Key Starts a repetitive sweep restarting at the end of each sweep MANUAL Key Enables the sweep circuitry It 0 does not start a sweep The TUNE knob if enabled or the FREQ INCREMENT ir and ays keys controli the sweep SINGLE Key Arms the single sweep and tunes the Signal Generator to the start frequency The sweep does not begin until the key is pressed again to trigger the sweep When pressed during a sweep the in progress sweep aborts and rearms the single sweep SWEEP RATE STEP Key Used as a prefix to the Data and Units keys to set the number of steps or the size of each step of a sweep When the entry is terminated by STEPS the number of steps is set When the entry is terminated by GHz MHz or kHz the step size is set When this key is pressed the number of steps is displayed on the left side of the FREQUENCY MHz display and the corresponding step size is displayed on the right side The maximum number of steps allowed is 9999 Figure 3 5 Sweep Features and LOCAL Key 1 of 2 3 13 Operation HP 8673H Serre race 9000 OOH DWELL Key Used as a prefix to the
283. steps from 10 to 90 dB with 10 to 3 dBm continuous level vernier AUTO PEAK function maximizes avail Blue SHI able output power at RF connector and ondary ft optimizes pulse modulation charac Keys cor teristics labeled v Refer to descripti 11 digit LED display for all frequency in related parameters and error malfunction messages ap or Af sweep is selectable o five synthesized markers FREQ keys when shifted to FREQ allow control of Annunciators monitor instrument modes ty multiplication and offset for confidence in operational status HP IB address displayed and set by front panel keystroke sequence FREQUENCY Misz pzyoo000 SWEEP RATE Rotary puise generator tuning knob and 4 lt lt up down increment keys change a frequency in user selected steps AUTO MANUAL and SINGLE digital sweep modes Frequency entered by function data and unit keys XFREQ key is used as a units key for entry of frequency multiplication factors access to sec tain keys Inctions are Store and recall up to 9 front panel 3n in blue settings for measurement efficiency Blue SHIFT key required for store function rough 3 6 for detailed eatures it Panel Features sow osv zv z395 393 zoom unctic 2th ese fe Fror 3 1 tion 2 tion 6 ution bd or sitivi ximur es 3 ges ximur ximur nod X nod X nod X Gi ad 10 MHz 3e Ing
284. suming the SOURCE SETTLED bit is not going to be set The status byte must be cleared with the CS program code before the frequency is changed If the status byte is not cleared the SOURCE SETTLED bit may have been set by a previous command the bit is latched until the status byte is read or cleared 500 SUB Settled 510 T_counter TIMEDATE l In case no source settled 520 Stat SPOLL 719 Serial poll 530 IF TIMEDATE T_counter gt 1 THEN Done Default of 1 second 540 IF NOT BIT Stat 3 THEN GOTO 520 Wait for set bit 550 Done 560 SUBEND Source is settled or 1 second has passed The following message numbers may be displayed when setting the frequency incrementor changing the frequency Each error message is explained as it pertains to setting the frequency increment or changing the frequency For a more complete description of the messages see the MESSAGES detailed operating instructions 01 Desired frequency is out of range Occurs in remote mode when a frequency decrement would place the new frequency below the Signal Generator s frequency range 02 Entered frequency increment is not within the capability of the Signal Generator Also occurs in remote mode when a frequency increment would place the frequency above the Signal Generator s frequency range 90 Auto Peak malfunction This indicates that the instrument may require service Operation HP 8673H Detailed Operating Instructions Frequency Modulation Description Th
285. t oscillator and oscilloscope to the Signal Generator as shown in Figure 3 9 HP 98673H SYNTHESIZED TEST OSCILLATOR SIGNAL GENERATOR OSCILLOSCOPE Figure 3 9 FM Functional Check Setup Saas emer aeaee 3 22 HP 8673H Basic Functional Procedure 37 cont d 38 39 40 Operation OPERATOR S CHECKS Checks cont d Slowly increase the output level of the test oscillator starting from OV u ntil the Signal Generator s meter reads full scale Verify that the meter increases slowly and continuously and that the FM OVERMOD status annunciator remains off The oscilloscope display should be approximately 1V peak Repeat step 37 for each of the following FM deviation ranges 0 1 0 3 1 3 and 10 MHz Set the Signal Generator s FM DEVIATION range to 10 MHz Increase the test oscillator output level until a full scale reading is obtained Decrease the test oscillator frequency slowly until the Signal Generators FM OVERMOD status annunciator turns on This should occur at a modulation frequency of 1 to 2 MHz modulation index approximately 6 5 Press FM DEVIATION MHz OFF and disconnect the test oscillator and oscilloscope from the Signal Generator Pulse Modulation Check Pulse modulation is checked using various front panel status annunciators Although pulse modulation is not monitored at the RF OUTPUT connector the status annunciators give a high degree of confidence that pulse modulation is functionally working
286. t the end of the sweep regardless of the sweep width The output impedance is nominally 100 ohms The TONE MKR connector provides a 5 kHz signal when an active marker frequency is generated This signal can be connected to the AM IN connector on the front panel to provide AM markers on the external display Nominal impedance of the TONE MKR is 600 ohms The BLANKING MARKER output provides a 5 volt signal at the beginning of each frequency change for blanking an external display The blanking function is used to eliminate the display of switching transients Once the frequency has settled the signal returns to 0 volts unless the new frequency is an active marker frequency If the frequency is an active marker frequency the signal is set to 5 volts to provide a Z axis input for intensifying the display at the marker sweep point The PEN LIFT connector provides control for an external X Y recorder A TTL logic high is used to raise the pen and a TTL logic low is used to lower the pen The pen is only lowered in single sweep and there is a 100 millisecond sweep delay for the pen to rise or lower To set the Signal Generator for automatic sweeping 1 Set the desired sweep parameters 2 Press the AUTO SWEEP MODE key to activate automatic sweep mode The key indicator will light and the display will indicate that a sweep is in progress with a start stop frequency display or a running indication of the RF output frequency If a new center frequency
287. t the proper zeroing point If the instrument does not operate properly and is being returned to Hewlett Packard for service please complete one of the blue tags located at the end of this manual and attach it to the instrument Refer to Section 2 for packagi instructions 3 8 Battery Replacement Yearly replacement of the internal battery is recommended to ensure prog operation of the memory circuitry See Service Sheet 26 of the HP 8673H Service Manual for the location of the battery WARNING To replace the battery the Signal Generator s protective covers must be removed This should only be done by service trained personnel who are aware of the hazards involved for example fire and electrical shock SIMPLIFIED OPERATION PRESETTING THE FRONT PANEL Press 0 to set the front panel to the following conditions RF OUTPUT to ON ALC Mode to INTERNAL RANGE to 70 dB except Options 001 and 005 RANGE to 0 dB for Options 001 and 005 only AUTO PEAK to ON Meter Scale to LVL AM FM and PULSE Modulation to OFF FREQUENCY to 9000 000 MHz FREQ INCR to 1 000 MHz START to 8000 000 MHz STOP to 10 000 000 MHz AF to 2000 000 MHz MERS to OFF initialized to 7 8 9 10 and 11 GHz SWEEP MODE to OFF STEP to 100 steps 20 000 MHz step size DWELL to 20 ms TUNE Knob to ON SETTING FREQUENCY Frequency and frequency increment values are set in a Function Data Units forme For example to set frequenc
288. t when the Auto Peak operation is completed However when sending several program codes in the same data string the SOURCE SETTLED bit may be set by one of the other Program codes For maximum assurance that the Auto Peak is finished an Auto Peak should be performed just before the RF output is used for a measurement Once the SOURCE SETTLED bit is set after sending the program code K1 Auto Peak On the RF output is settled and the Auto Peak operation is finished The multiplied bands are defined as 6 6 12 3 GHz for band 2 and 12 3 18 0 GHz for band 3 When using a frequency increment that is less than the specified frequency resolution there will be hysteresis about the band crossing points For example if the frequency increment is set to 1 kHz and the frequency is incremented from below 6 6 GHz to at least two increments above 6 6 GHz tuning back to 6 6 GHz will leave the 6 6 GHz output in band 2 instead of band 1 Incrementing less than one increment past a band point will leave the band point in the lower band When tuning upward from the 6 6 GHz band point with 1 kHz resolution the first increment will change the frequency to 6 6000002 GHz The second increment will not change the frequency but tuning back to 6 6 GHz will leave the 6 6 GHz frequency in band 2 This hysteresis will affect subharmonics the 2 6 6 GHz fundamental feedthrough and multiples of the subharmonics The following programs are written in BASIC for HP 9000 S
289. tant amplitude over the Signal Generator s frequency range For example if a cable is used that has a constant 0 5 dB GHz loss a level error of 5 dB would occur after a 10 GHz frequency change The signal at the RF output connector of the Signal Generator has not changed but an extra 5 dB of attenuation is introduced in the signal path when the output frequency is changed The detection of the signal level can be done using a power meter with an appropriate sensor The power meter must have an output signal that is proportional to the signal level in watts The recorder output of most power meters provides the feedback signal for power meter leveling External ALC using a power meter has the advantages of temperature compensation and wide dynamic range Using a sensitive power sensor allows ALC at levels as low as the power meter and sensor can measure The disadvantage of power meter leveling is the longer settling time and the added complexity of a separate instrument To set the Signal Generator for power meter leveling 1 Connect the power meter to the remote point using a directional coupler or a power splitter The power meter sensor must have enough dynamic range to measure the level at the coupled port of the directional coupler For example to level a signal of 7 to 0 dBm using a 10 dB coupler the power sensor must be capable of measuring 17 to 10 dBm in a single range 2 Press the Signal Generator ALC INT key to set automatic l
290. te 6 6 GHz 10 100 1k 10k 100k 1M 10M Offset From Carrier Hz Add 6 dB for 6 6 to 12 3 GHz and 10 dB for 12 3 to 18 0 GHz Residual FM In CW and FM Modes 2 0 to 6 6 GH2 noise and power line related Mode FM Range Post Detection Bandwidth 300Hz 3kHz S50Hz 15kHz CW 30 and 100 kHz V 12 Hz rms 60 Hz rms 15 Hz rms 75 Hz rms 300 kHz V and 1 3 and i0 MHz V Residual FM doubles for 6 6 to 12 3 GHz and triples for 12 3 to 18 0 GHz Spurious Signals CW and AM modes Option 003 Instruments 400 Hz line operation Power line related and fan rotation related within 5 Hz below line frequency and multiples thereof Frequency Offset_from Carrier Range GHz lt 2 kHz 2 to 8 kHz gt 2 0 6 6 gt 6 6 12 3 gt 12 3 18 0 RF OUTPUT Output Level Switching Time to be within 1 dB of final level with no range change Operating Mode Output Level Switching Time CW lt 15 ms AM Pulse Sweep lt 5 ms For power settings gt 0 dBm changes in frequency of several GHz in one step may require additional AUTO PEAK enabling to stabilize power at the desired level Spurious output oscillations may occur for settings above 8 dBm HP 8673H Table 1 2 Supplemental External leveling device characteristics will determine output flatness absolute level accuracy and switching time in external leveling modes Impedance 50 ohms Source SWR lt 2 0 Output Level Accuracy
291. te of all the checks that failed Refer to the Service Manual for the appropriate troubleshooting procedures to follow if the Signal Generator is to be repaired at the user s facility If the instrument is to be returned to Hewlett Packard for repair fill out a blue repair tag found at the end of this manual Include on the back of the tag a list of all checks that failed and attach the tag to the instrument This will give the repair technician a good description of the malfunction and help assure the best possible service and the shortest repair time Test Oscillator Pulse Generator 0 HP 8013B or HP 8116A Oscilloscope HP 1980B Attenuator 10 dB HP 8491B Option 006 Turn On Check 1 Set the LINE switch to STBY Remove all external cables from the front and rear panels of the Signal Generator including the power cable connecting the instrument to mains power 2 Set the rear panel FREQ STANDARD INT EXT switch to INT 3 Connect the short jumper A3W3 between A3J9 and A3J10 4 After the power cable has been disconnected from the Signal Generator for at least 1 minute reconnect it to the Signal Generator Check the front panel of the instrument to verify that the STANDBY and OVEN COLD status annunciators are on 5 Leave the LINE switch set to STBY until the OVEN COLD status annunciator turns off This should occur in 15 minutes or less depending upon how long the Signal Generator was disconnected from mains power
292. tead of 10 milliwatts 10 dBm The RF output signal would be reduced for a detected level of 10 milliwatts which would reduce the amplitude of the fundamental and introduce an error in the leveled RF output Example 1 External ALC over the range of 0 to 10 dBm is required The RF signal path exhibits an insertion loss of 4 dB that varies 2 dB over the frequency range To control the output level over a 0 to 10 dBm range an amplifier capable of 16 dBm 10 dBm 4 dB 2 dB is required The range selected for this application depends mainly on the gain of the amplifier If we assume a gain of 10 dB the optimum Signal Generator range is 0 dB The overall signal path gain varies from 12 to 16 dBm To reduce the Signal Generator output level to 10 dBm would require 10 dB of attenuation The range is set 10 dB above this requirement or 0 dB Example 2 The IF output of a mixer is to be leveled at 20 dBm The conversion loss of the mixer is 10 dB and varies 3 dB over the frequency range Using the Signal Generator as the RF source for the mixer the diode detector is connected to the IF port of the mixer using a 10 dB directional coupler This will place the power at the diode at 30 dBm which is within the square law region of the detector The attenuation of the signal path is 10 dB and varies 3 dB For an IF level of 20 dBm the RF port must be at a level of approximately 10 dBm The range selected for the Signal Generator would then
293. termined by the amplitude setting of the external oscillator used to provide the modulating signal If the output impedance of the external oscillator is 600 ohms the AM depth can be determined by the controller by reading the external oscillator amplitude and multiplying by the programmed Signal Generator AM range To modulate the Signal Generator at 75 AM depth Local 1 Press the AM 100 key to set the Signal Generator to AM mode Press the AM key near the Signal Generator s front panel meter to set the meter to AM mode 3 45 Operation HP 8673H Detailed Operating Instructions Example cont d Program Codes Commenis 3 46 Amplitude Modulation conta 2 Set the extemal oscillator to the desired modulating rate and adjust the amplitude to zero volts 3 Connect the external oscillator to the Signal Generator s AM input connector Adjust the external oscillator amplitude until the middle scale 0 to 1 indicates 75 AM depth The required external oscillator amplitude will be approximately 0 75 volts peak or 0 53 volts rms Remote The programming string for setting the 100 AM depth range is A3 The amplitude and frequency of the modulating signal must be set by programming the external modulating signal source The alpha character A can be sent as upper or lower case Program Description Code AO AM Off AM Off AM 30 Range AM 100 Range oA tt men pam nah AM bandwidth is determined by the frequ
294. the specified limits 0 1 to 1 Vrms into 508 its level may be sufficient to turn off the UNLOCKED status annunciator giving a false indication of normal operation In fact the phase noise of the Signal Generator may be degraded 3 12 ADDITIONAL OPERATING INFORMATION Signal Generator performance can be optimized by considering the effect of the following controls on the RF output a Auto Peak b ALC c Pulse Modulation d Sweep mode in a Master Slave configuration HP 8673H 3 13 Auto Peak Major power and pulse modulation specifications are not warranted unless an AUTO PEAK operation has been performed An AUTO PEAK operation is automatically performed when the frequency changes by more than 50 MHz while AUTO PEAK is enabled AUTO PEAK is automatically enabled when the instrument is tured on or when PULSE mode is selected The front panel AUTO PEAK button toggles the state of the instrument between AUTO PEAK enabled and disabled mode A user initiated AUTO PEAK operation may be performed manually at any time by pressing the AUTO PEAK button twice to disable and re enable AUTO PEAK The actual peaking operation occurs when the AUTO PEAK is switched from the disabled to enabled mode For more information about Auto Peak see the detailed operating instructions 3 14 ALC Automatic Level Control Output power leveling for the instrument s frequency range occurs from sources selected by the operator These sources ar
295. the RF output frequency in discrete steps from the start frequency to the stop frequency The number of steps that the Signal Generator produces between the start and stop frequency is controlled by the number of steps or the sweep step size parameters The Signal Generator has three sweep modes to accommodate a variety of applications Auto sweep mode is used when a repetitive sweep is required Auto sweep mode will step the RF output frequency from the start frequency to the stop frequency and then repeat the sweep until the sweep is turned off or a band crossing is encountered Single sweep mode will step the RF output frequency from the start frequency to the stop frequency once and then stop This mode is useful when a single sweep is required for a measuring device to store the results Additional control signals are provided for control of X Y recorders and extemal displays Manual sweep provides a convenient method to limit the tuning range of the frequency tuning controls In applications requiring a single band of frequencies the tuning limits can be set to cover the band of interest which allows the user to tune the frequency without having to watch the Signal Generator display to determine when the frequency is outside of the selected band There are four rear panel connectors that are used for sweep coordinating signals SWP OUT provides a signal that is 0 volts at the beginning of a sweep and 10 volts at the end of the sweep regardles
296. the Signal Generator 3 75 Operation HP 8673H Detailed Operating Instructions Example cont d Program Codes 3 76 Frequency Increment and Tuning conta The frequency increment could also have been entered as 0015 GHz or 1500 kHz The only difference is the placement of the decimal point and the units key pressed after the frequency increment has been entered using the numeric keypad Remote The programming string for setting the frequency increment is composed of a program code numeric data and the units terminator The frequency increment may be programmed in units of GHz MHz kHz or Hz To program the Signal Generator for a 1 5 MHz frequency increment the possible program strings are FLOISGZ or FI1 5M2 or FISQ0KZ or FI1500000HZ In addition the program code could be FN or F1 instead of FI The alpha characters can be sent as upper or lower case or even mixed upper and lower case To increment the frequency in 1 5 MHz steps send the program code UP To decrement the frequency in 1 5 MHz steps send the program code DN A single step will be made for each program code received To increment or decrement more than one step send a program string with multiple program codes For example DNDNDNDN will decrement the frequency four times Program Code SEI FN FL Frequency Increment Codes Units Frequency Increment Hf MZ KZ HZ Preferred Program Code F
297. tically by subject and are placed at the end of this section for easy reference They are also indexed by subject in Table 3 7 Panel Features Front and rear panel features are described in detail in Figures 3 1 through 3 7 3 5 Remote Operation 4R HP IB The Signal Generator is capable of remote operation via the Hewlett Packard Interface Bus HP IB In remote operation the Signal Generator operates in one of three modes normal talker listener talk only or listen only The HP IB operating instructions are found in paragraphs 3 23 through 3 45 These instructions relate to remote operation including capabilities addressing input and output formats the Status byte and service requests At the end of the discussion is a complete summary of all codes In addition to the section described above information concerning remote operation appears in several other locations Numerous examples of program strings appear throughout the Detailed Operating Instructions described under Local Operation above Auxiliary The following keyboard functions can be controlled by TTL signals at the rear panel AUX connector RECALL 1 FREQ INCREMENT up and down SINGLE Sweep In addition several remote only functions are available These controls are described in detail in paragraphs 3 19 through 3 22 3 6 Operator s Checks Operator s Checks are procedures designed to verify the proper operation o fthe Signal Generator s main PRESE
298. to listen Then the Signal Generator must receive a Data message with the appropriate program code When the Signal Generator is addressed to talk it will output data for the selected talk function If the controller does not repeat the program code or send a new one the Signal Generator sends data for the last selected talk function when it is addressed to talk However it is recommended that a talk function program code be sent each time prior to addressing the Signal Generator to talk This will ensure that the Signal Generator sends the appropriate data Refer to Table 3 4 for a summary of talk functions Front Panel Learn Mode The front panel learn mode uses the controller s memory to learn and store a data string that describes the Signal Generator s current front panel setting Once an instrument state has been learned the Signal Generator can be restored to that configuration at a later time The learn mode requires a controller that can transfer information in binary form After receiving an L1 program code Front Panel Learn Mode and when addressed to talk the Signal Generator sends 2 ASCII characters and A followed by a string of 94 8 bit binary bytes containing information on the front panel configuration This binary data can then be stored in the controller s 3 37 Operation a gt Sending the Data Message cont d memory for future use In addition as each configuration goes out onto the bus it is also st
299. to talk the Signal Generator sends the binary byte that it just received Refer to Section 8 Service for additional information HP 8673H Operation gt Table 3 4 Talk Functions Funeten Program Code Signal Generator Signal Generator Output Response to Program Code Response to Program Code Comments Troit ass Learn Mode P ae pe piney Bytes EOI MESE Special Function Learn heel 26 Binary Bytes EOI See Section 8 Service Mode Output Active Program Program Code Numeric Value Units Terminator Valid Functions CF Parameter Code OA LF and EOI FI FA FB FS M1 5 DW LE VE RA Output Sweep Steps SPOA SP Step Size HZ SP of Steps SS Step Size LF and EO Output Couple START Value Center Frequency Frequency is in Hz Value Dwell Value LF and EOI dwell is in milliseconds Output Lock Frequency x FR Numeric Value Hz LF and EOI Bares Sending the Data Message cont d Table 3 5 Response to a Clear Message Execution Mode immediate Cleared Cleared Cleared Cleared set to 00 ON INTERNAL Output Status After receiving the program code OS Output Status and when addressed to talk the Signal Generator sends two binary bytes each 8 bits wide The first byte is identical to the Status Byte of the Serial Poll The second byte is the Extended Status Byte which provides additional information See Figure 3 11 for a description
300. top frequency to 11 232 334 MHz Local 1 Press the SWEEP FREQ STOP key 2 Key in 11232 334 using the numeric keypad The FREQUENCY MHz display should show 11232 334 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the MHz units key to finish the sequence The FREQUENCY MHz display should show the entered frequency until the units key is released The FREQUENCY MHz display should now be right justified The frequency could also have been entered as 11 232334 GHz or 11232334 kHz The only difference is the placement of the decimal point and the units key pressed after the frequency has been entered using the numeric keypad Remote The programming string for setting the sweep stop frequency is composed of a program code numeric data and the units terminator The frequency may be programmed in units of GHz MHz kHz or Hz To program the Signal Generator start frequency to 11232 334 MHz the possible program strings are FB11 232334G2 or FB11232 334MZ or FB11232334KZ or FB11232334000HZ The alpha characters can be sent as upper or lower case or even mixed upper and lower case If the CW frequency changes the output frequency is valid once the SOURCE SETTLED bit of the status byte is set see Comments HP 8673H Program Codes Comments Programming Example 3 Operation Detailed Operating Instructions Stop Frequency Sweep cont d Coda Units GZ FB Sta
301. tor 5 Ifthe UNLEVELED annunciator is on step the range up or down until the UNLEVELED annunciator is extinguished The UNLEVELED annunciator indicates that the Signal Generator is unable to supply enough power because the signal path has too much attenuation or that the ALC circuitry cannot attenuate the Signal Generator s RF level enough to achieve leveling HP 8673H Local Procedure cont d Remote Procedure Example Operation Detailed Operating Instructions System Automatic Level Control conta 6 When the Signal Generator is in the 0 10 and 20 dB ranges the system RFoutput level is equal to the sum of the RAN GE and VERNIER settings Range settings below 0 dB add attenuation to the signal path and do not affect the system level until the ALC goes unleveled The equipment setup for remote control of system leveling is the same as the local procedure The program code for system ALC is C4 The system level can be remotely controlled directly for power levels between 0 and 23 dBm For levels between 0 and 10 dBm the RANGE should be set to 0 dB and the VERNIER programmed for the appropriate level Using a range less than 0 dB while using external system leveling will have no effect on the level but can force the Signal Generator to lose control of the level due to insufficient attenuation lack of ALC dynamic range or too much attenuation attempted operation beyond maximum power specification The VERNIER and RANGE
302. tor sends the Status Bit message This check can be performed in either local or remote mode If the Signal Generator s SRQ annunciator is off perform the first part of the Require Service Message check before beginning this check If a series 200 300 controller is used two short programs are required to perform this check Description Serles 200 300 HP 85B BASIC 10 PPOLL CONFIGURE Configure the Signal Generator to respond to a parallel poll on HP IB data line DI03 719 10 20 V PPOLL 7 SEND 7 LISTEN 19 CMD 5 SCG 10 V PPOLL 7 Place the Signal Generator in parallel poll mode causing it to send the Status Bit message and store the result in variable V Display the value of V 30 DISP V 40 END Check that the SRQ annunciator is on and that the response to the parallel poll is 4 indicating that the Signal Generator issued the Status Bit message Description Series 200 300 HP 85B BASIC Unconfigure the Signal Generator from 10 PPOLL responding to a parallel poll UNCONFIGURE 719 20 V PPOLL D SEND 7 LISTEN 19 CMD 5 SCG 18 Place the Signal Generator in parallel V PPOLL 7 poll mode 30 DISP V DISP V 40 END Display the value of V Check that the SRQ annunciator is on and that the response to the parallel poll is 0 indicating that Signal Generator is no longer configured to respond to a parallel poll Then turn the LINE switch t
303. tore a state in register 0 This register is reserved for instrument preset conditions 92 The data stored in the register being recalled has been corrupted The instrument will be reset HP 8673H Description Local Procedure Remote Procedure Exampie Program Codes Comments Operation Detailed Operating Instructions RF Output On Off The RF output of the Signal Generator can be disabled with the RF ON OFF key on the front panel The RF output can be disabled when the minimum power level setting is not low enough to prevent interference as when zeroing a power meter using a high sensitivity power sensor With the RF output disabled the UNLEVELED and gUNLOCKED annunciators will turn on to indicate that the microwave signal source is disabled In addition if frequency modulation is enabled the FM OVERMOD annunciator will also light To turn off the RF output 1 Press the RF ON OFF key The indicator on the key will be lighted whenever the RF output is enabled and extinguished when the RF output is disabled Pressing the key repeatedly will toggle the RF output between the on and off state The Signal Generator RF output is turned on or off using a single program code The program code to turn the RF output on is RF1 or R1 The program code to turn the RF output off is RFO or RO To turn off the RF output Local If the indicator in the RF ON OFF key is not lighted the RF output is already off If the indicator
304. trol line REN false The Signal Generator can also be switched to local by pressing the front panel LOCAL key assuming Local Lockout is not in effect With the exception of VERNIER which returns to the front panel setting the Signal Generator s control settings remain unchanged with the Remote to Local transition Local Lockout When a data transmission is interrupted which can happen by pressing the LOCAL key to return the Signal Generator to local mode the data could be lost This would leave the Signal Generator in an unknown state To prevent this a local lockout is recommended for purely automatic applications Local lockout disables the LOCAL key and allows returm to local only under program control NOTE Return to local can also be accomplished by turning the Signal Generator s LINE switch to STBY then back to ON However this technique has some disadvantages a It defeats the purpose and advantage of local lockout that is the system controller loses control of a system element b There are several HP IB conditions that reset to default states at turn on Operation HP 8673H Table 3 3 Message Reference Table 1 of 2 Related HP IB Appli Commands Controls Most front panel functions and remote only functions are bus program mable Front panel functions that are not programmable are the line switch and the HP IB address Clear Lockout Set Local If in remote and address
305. tude modulation up to 75 depth at rates as high as 100 kHz is typically available using external diode leveling mode Program Codes The response time for a level change using diode leveling mode will typically be about 1 millisecond in CW mode and about 0 1 millisecond in AM mode The square law region for a point contact diode is typically 45 to 20 dBm The square law region for a Schottky hot carrier diode is 50 to 20 dBm External diode leveling is not temperature compensated Power drift over temperature is dependent on the detector used Frequency recalibration may be required in environments that are not temperature stabilized The Signal Generator range selected will have a direct affect on ALC The range selected depends primarily on the losses and gains in the RF signal path In most applications the ALC dynamic range is limited by the maximum RF power available at a given frequency For example with 15 dB of loss in the signal path the Signal Generator must compensate with at least 15 dB of additional RF output power With no internal attenuation 0 or 10 dB ranges the Signal Generator would have to supply 15 dBm for a leveled signal at 0 dBm Since the maximum RF output power is specified at less than 13 dBm the Signal Generator may not be able to supply the required power Output level ranges of 10 to 90 dB add attenuation to the RF signal path These ranges are useful mainly when attempting to level low am
306. tuning controls allow convenient control for setting frequency Tuning with the TUNING knob is useful for observing a range of frequencies and still being able to speed up or slow down the tuning as desired In addition the frequency increment may be decreased if finer resolution is desired around a specific frequency The frequency increment step keys are very useful for tuning between channels with a fixed channel spacing Setting the frequency increment to the channel spacing allows easy stepping with a single key press In addition holding down the frequency increment step key will allow stepping at a rate of about ten steps per second This power tune feature does not offer as much control as the TUNING knob because the stepping rate is fixed for the frequency increment step keys Signal Generator frequency settings can be stored in memory for later use The nine store recall registers of the Signal Generator allow up to nine different front panel settings to be stored and recalled This feature is useful when several unrelated frequencies are required To set the Signal Generator to a specific frequency 1 Press the FREQUENCY key to indicate that the next entry will be for CW frequency 2 Enter the desired frequency using the numeric keypad If a mistake is made while entering the frequency press the backspace key until the incorrect digit disappears Continue entering the correct digits until the frequency displayed in the FREQUENCY
307. ue entering the correct digits until the dweil time in the FREQUENCY MHz display is correct 3 Press the ms key to finish the sweep dwell time entry The dwell time will be displayed until the ms key is released The Signal Generator accepts any dwell setting between 1 and 255 milliseconds The format of the remote programming follows the front panel key sequence The program code DW is sent followed by the desired dwell time and the units MS The dwell times can be read by the controller using the output active program code suffix To read the current dwell time the program string DWOA is sent and then the dwell time is read If read as a string the format is the program code DW followed by the dwell time in milliseconds and the units terminator MS To set the sweep dwell time to 20 milliseconds Local 1 Press the DWELL key 2 Key in 20 using the numeric keypad The FREQUENCY MHz display should show 20 when you have finished keying in the value Note that the entry is left justified at this point 3 Press the ms units key to finish the sequence The FREQUENCY MHz display should show the entered dwell time until the ms key is released Remote The programming string for setting the dwell time is composed of a program code numeric data and the units terminator To program the dwell time to 20 milliseconds the program string is DW20MS The alpha characters can be sent as upper or lower case or even mixed upper and low
308. ulation detailed operating instructions for more information about AM bandwidth while in sweep mode The front panel annunciators are filtered in sweep mode to prevent false indications While sweeping the frequency changes cause a loss of phase lock and unleveled automatic level control during the frequency change To prevent constant flashing of the front panel annunciators the response is damped to indicate only major problems during a sweep The bits of the extended status byte are also buffered and should not be used to check individual sweep points for phase lock and leveled RF output 3 123 Operation HP 8673H Detailed Operating Instructions Single Sweep Mode conta Programming The following program is written in BASIC for HP 9000 Series 200 or 300 controllers The Example program is used to set the Signal Generator to the sweep mode specified by the variable Mode 180 190 SUB Sweep_set Err Mode OUTPUT 719 USING 2A MG i Read message from 8673 ENTER 719 USING 2A Message to clear any old messages SELECT Mode CASE AUTO AUTOMATIC Code W2 Auto sweep mode CASE MANUAL Code W3 CASE SINGLE ONCE Code W6 l Arm and begin single CASE ELSE DISP WARNING Invalid sweep mode specified Err 1 SUBEXIT END SELECT l OUTPUT 719 USING 2A Code SUBEND End of subroutine Error The following message numbers may be displayed when activating single sweep mode E ach Messages me
309. ument However if the power up sequence including the memory checks and the front panel operation is good the program codes in all likelihood will be correctly implemented The validity of these checks is based on the following assumptions a The Signal Generator performs properly when operated via the front panel keys that is in local mode This can be verified by the Basic Functional Checks b The bus controller properly executes HP IB operations c The bus controller s HP IB interface properly executes the HP IB operations If the Signal Generator appears to fail any of these HP IB checks the validity of the above assumptions should be confirmed before attempting to service the instrament The select code of the controllers HP IB interface is assumed to be 7 The address of the Signal Generator is assumed to be 19 its address as set at the factory This particular select code address combination that is 719 is not necessary for these checks to be valid However the program lines presented here have to be modified for any other combination These checks can be performed together or separately Any special requirements for a check are described at the beginning of the check Initial The test setup is the same for all of the checks Connect the Signal Generator to the bus Setup controller via the HP IB interface Equipment HP IB Controller e sanang HP 85B 82903A 16K Memory Module 00085 15005 Advanced Programming ROM
310. unctions can be line produces one 5 fs low going pulse at the end of controlled through the rear panel AUX connector each sweep The Trigger line produces one 5 us low These functions are listed in Table 3 2 below going pulse when the Signal Generator has made a The input lines are TTL compatible and negative edge large frequency change that may cause loss of phase sensitive They require a minimum of 5 jis between lock in an instrument tracking the Signal Generator negative edges Input signals can be generated by clean The Negative Blanking line produces 5V for Z axis TTL drivers or by mechanical switches that require blanking of CRT displays that require a negative debouncing The Signal Generator has a built in blanking voltage debouncing circuit that should be enabled or bypassed depending upon which type of driver is used 3 23 REMOTE OPERATION gt p The Signal Generator can be operated through the The Signal Generator is shipped from the factory Hewlett Packard Interface Bus HP IB Bus configured for electrically clean control signals i e compatibili rogramming and data formats are the internal debouncing circuit is bypassed Refer to PAREN d Erue WiN iat apis Figure 2 5 in Section 2 Installation for the procedure g paragraphs for enabling or bypassing the debouncing circuit Most front panel functions and remote only functions are bus programmable Front panel functions that are NOTE not programmable are the line swit
311. units key is pressed the displayed frequency will be adjusted to display MHz and the output frequency will be set If a sweep mode is active when sweep center frequency is entered the actual frequency displayed after pressing the units key will usually not be the entered frequency The FREQUENCY MHz display is used to display sweep information during sweep mode so the new sweep center frequency will not be displayed Setting the sweep center frequency during a sweep changes the center frequency to the value entered If auto sweep is enabled the sweep will continue about the new center frequency If manual sweep is enabled the sweep frequency will be reset to the new start frequency For single sweep the frequency will reset to the new start frequency and the sweep will remain armed The center frequency can be tuned in the same manner as CW frequency except when manual sweep mode is active To check the current sweep center frequency during sweep press and hold the FREQUENCY key The FREQUENCY MHz display will display the sweep center frequency as long as the key is held HP 8673H Remote Procedure Example Program Codes Operation Detailed Operating Instructions Center Frequency Sweep contd The Signal Generator accepts any frequency within its specified frequency range A bo ve 6 6 GHz the programmed frequency may be rounded by the Signal Generator to be compatible with the 2 or 3 kHz resolution at the programmed frequency
312. urance of whether the power will go up go down or stay the same 3 31 Data Messages The Signal Generator communicates on the interface bus primarily with Data messages Data messages consist of one or more bytes sent over the bus data lines when the bus is in the data mode attention control line ATN false Unless it is set to Talk Only 3 36 HP 8673H the Signal Generator receives Data messages when addressed to listen Unless it is set to Listen Only the Signal Generator sends Data messages or the Status Byte message when addressed to talk Virtually all instrument operations available in local mode can be performed in remote mode via Data messages The major exceptions are changing the LINE switch settings and changing the HP IB address of the Signal Generator 3 32 Receiving Data Messages The Signal Generator responds to Data messages when it is enabled to remote REN control line true and it is addressed to listen The instrument remains addressed to listen until it receives an Abort message or until its talk address or a universal unlisten command is sent by the controller Data Message Input Format The Data message string or program string consists of a series of ASCII codes Each code is typically equivalent to a front panel keystroke in local mode and follows one of three formats Program Code Numeric Value Units Ter minator EOS e Program Code Numeric Value EOS Program Code EO
313. ure 1 1 Procedures for checking electrical performance are given in Section 4 If the contents are incomplete if there is mechanical damage or defect or if the instrument does not pass the electrical performance test notify the nearest Hewlett Packard office If the shipping container is damaged or the cushioning material shows signs of stress notify the carrier as well as the Hewlett Packard office Keep the shipping materials for the carrier s inspection 2 3 PREPARATION FOR USE 2 4 Power Requirements The Signal Generator requires a power source of 100 120 220 or 240 Vac 5 to 10 48 to 66 Hz single phase for Option 003 instruments 400 Hz single phase and 120 Vac 5 10 only Power consumption is 400 VA maximum This is a Safety Class I product that is provided with a protective earth terminal An uninterruptible safety earth ground must be provided from the main power source to the product input wiring terminal power cable or supplied power cable set Whenever it is likely that the protection has been impaired the product must be made inoperative and be secured against any unintended operation If this instrument is to be energized via an external autotransformer make sure the auto transformer s common terminal is connected to the neutral that is the grounded side of the mains supply 2 5 Line Voltage and Fuse Selection BEFORE PLUGGING THIS INSTRUMENT into the mains line voltage be sure the c
314. us negative true TTL pulse REMOTE PROGRAMMING All functions HP IB programmable except LINE switch and HP IB address switch Output Data Frequencies and output level settings error malfunction messages operational status and learn mode strings SH1 AHI T5 TEO L3 LEO SR1 RL1 PP1 DCI DT1 CO El Interface Function Codes HP 8673H General Information Table 1 1 Specifications 6 of 6 Electrical Characteristics Performance Limits Conditions REAR PANEL CONNECTORS Frequency Reference Output Sweep Output Tone Marker Output Z Axis Blanking Marker Penlift 10 MHz Output 100 MHz Output GENERAL Operating Temperature Range Power Requirements Line Voltage 100 120 220 or 240V Power Dissipation Conducted and Radiated Electromagnetic Interference Net Weight Dimensions Height Width Depth 0 5 V or 1 V GHz 18 V maximum Factory set to 0 5 V GHz Intemal switch provides 1 V GHz capability 0 to 10 V ramp start to stop Maximum level adjustable between 4 V and 12 V 5 kHz sine wave output Z Axis control for CRT Compatible with devices that have penlift control 0 dBm nominal into 50 ohms 0 dBm nominal into 50 ohms 0 to 55 C except specifications for harmonically related spurious signals RF output pulse peak level accuracy and amplitude modulation which are limited to 15 to 35 C 5 10 400 V A maximum MIL STD 461A 196
315. weep W6 when the Trigger message is received 3 36 Receiving the Remote Message The Remote message has two parts First the remote enable bus control line REN is held true second the device listen address is sent by the controller These two actions combine to place the Signal Generator in remote mode Thus the Signal Generator is enabled to go into remote when the controller begins the Remote message but it does not actually switch to remote until addressed to listen the first time When actually in remote the Signal Generator s front panel RMT annunciator lights 3 37 Receiving the Local Message The Local message is the means by which the controller sends the Go To Local GTL bus command If addressed to listen the Signal Generator returns to front panel control when it receives the Local message When the Signal Generator goes to local mode the front panel RMT annunciator turns off However even when in local if the Signal Generator is being addressed its front panel LSN or TLK annunciator turns on 3 38 Receiving the Local Lockout Message The Local Lockout message is the means by which the controller sends the Local Lockout LLO bus command If in remote the Signal Generator responds to the Local Lockout Message by disabling the front panel LOCAL key The local lockout mode prevents loss of data or system control due to someone accidentally pressing front panel keys If while in local the Signal Generat
316. when the sweep step size is entered The Signal Generator is capable of 1 to 9999 steps within a sweep span as long as the calculated step size is greater than 1 kHz For a sweep with one step the Signal Generator will produce the start frequency and the stop frequency Sweep step size can be set between 1 kHz and the currently defined sweep span as long as the calculated number of steps is between 1 and 9999 steps Entering a sweep step size larger than the sweep span will set the step size equal to the span and will cause the Signal Generator to issue a message To set the number of sweep steps 1 Press the STEP key to indicate that the next entry will be for the sweep step size or the number of steps The only difference in entering the two parameters is the units terminator 2 Enter the desired number of steps using the numeric keypad If a mistake is made while entering the number of steps press the backspace key until the incorrect digit disappears Continue entering the correct digits until the number of steps in the FREQUENCY MHz display is correct 3 Press the STEPS key to indicate that the number of steps rather than the sweep step size has been entered The sweep step size will be calculated and the sweep step size and the number of steps will be displayed until the STEPS key is released If the entered value does not produce a sweep step size equal to or greater than the frequency resolution the number of steps will be reduc
317. will automatically adjust the number of steps to 10 to accommodate the minimum frequency resolution of 1 kHz 90 Auto Peak malfunction This indicates that the instrument may require service HP 8673H Description Local Procedure Remote Procedure Program Codes Operation Detailed Operating Instructions Messages MESSAGE is a two digit code that indicates errors The error code indicates either a data entry error or a hardware malfunction When the error is an entry error the MESSAGE indicator on the front panel lights When the error is a hardware malfunction the MESSAGE indicator flashes To read the error code press the MESSAGE key on the front panel The two digit code will appear in the FREQUENCY MHz display when this key is pressed After reading the code consult Table 3 8 Error Messages for an explanation of the error codes The error code will remain in the FREQUENCY MHz display as long as the MESSAGE key is pressed Once the message is read however the error code is cleared to 00 no error whether or not the causing condition has been corrected Types of error codes Messages 01 through 09 are front panel entry errors The entry is ignored and the previous parameter value is retained Messages 10 through 16 are errors that result from unusual combinations of sweep entries A message is displayed and all entered values are stored in anticipation that further entries will resolve the conflict Messages 30
318. will be offset by the current offset frequency Note that all frequencies except sweep step size and sweep frequency span are offset HP 8673H Remote Procedure cont d Example Program Codes Operation Detailed Operating Instructions Offset Frequency conta The format of the remote programming uses a program codeto specify frequency offset followed by the desired offset frequency and the appropriate units terminator GZ MZ KZ or HZ Entering a negative frequency specifies a negative offset and entering a positive frequency specifies a positive frequency offset Once the offset frequency is programmed the controller can read the entered value using the output active program code suffix To read the offset frequency send the program string FTOA and then read the actual frequency offset If the offset frequency is read as a string the format will be the program code FT followed by the frequency offset positive or negative in Hz and then the units terminator Hz To set a frequency offset of 63 238 MHz Local 1 Press the blue shift key to indicate that a shifted function is to be accessed The shifted functions are printed in blue above certain keys 2 Press the OFFSET key if the displayed frequency is to be above the actual RF output frequency Press the OFFSET key if the displayed frequency is to be below the actual RF output frequency 3 Key in 63 238 using the numeric keypad The FREQUENCY MHz display oats s
319. will not be multiplied by the display multiplier Remote The programming string for setting the display multiplier to 2 is MY2XF The alpha non numeric characters can be sent as upper case or lower case or even upper and lower case Once a display multiplier is entered all frequencies except offset will be multiplied by the entered multiplier This allows the controller to read the system frequency over the bus and also the multiplier in case the Signal Generator s actual RF output frequency is to be determined Program Function Applicable Code Units MU Display Multiplier MY Frequency multiplication reduces the frequency resolution of the multiplied frequency For example an RF output frequency of 12 GHz corresponds to a frequency resolution of 2 kHz If an external frequency doubler multiplier 2 is used the 24 GHz multiplied frequency would have a frequency resolution of 4 kHz When a frequency offset and a display multiplier are entered the displayed frequency is multiplied before being offset For an application such as a harmonic mixer the desired harmonic can be entered as the multiplier and the desired IF frequency as an offset Once these two values are entered the frequency that is to be downconverted can be entered directly on the Signal Generator The actual Signal Generator frequency will be the entered frequency offset by the IF frequency and then divided by the harmonic multiplier The calculations are
320. witching to remote to read the VERNIER Setting and then returning the Signal Generator to local mode The VERNIER setting is read by sending the program codes VEOA and then reading the setting The Signal Generator will send the VERNIER setting in fundamental dBm units If the VERNIER setting is read as a string the format will be the program code VE followed by the VERNIER setiing in dBm and then the units terminator DM dBm The RF output level is read directly by sending the program codes LEOA and then reading the RF output level The Signal Generator will send the RF output level in fundamental dBm units If the RF output level is read as a string the format will be the program code LE followed by the RF output level in dBm and then the units terminator DM dBm The program codes AP or PL can also be used in place of LE but the Signal Generator will always send the program code LE when the RF output level is read as a string i To set the RF output level to 56 dBm Local 1 Press the ALC INT key to place the Signal Generator into internal ALC mode The process for setting the RF output level for external ALC modes is covered under the appropriate section of the Detailed Operating Instructions 2 Set the RANGE to the lowest range that is less than 10 dB above the power or 50 dBm in this case 3 Adjust the VERNIER until the level meter indicates 6 dBm For the 50 dBm RANGE the VERNIER can adjust the output level from 60 to
321. y not be re initialized and pending Service Requests may get lost 3 44 Sending the Status Bit Message The Signal Generator sends the Status Bit message if configured as part of the interface s response byte to the Parallel Poll Enable PPE bus command In order for the Signal Generator to respond to a Parallel Poll Enable bus command it must be assigned a single HP IB data line by the controller The controller also assigns the logic level of the bit Both tasks can be accomplished by the Parallel Poll Configure PPC bus command If the Signal Generator is sending the Require Service message it will set its as signed status 3 41 Hanes HP 8673H BIT 7 WEIGHT es ae ET WEIGHT 128 7 Condition 0 ALC Un Power always leveled Fail ure On Request Service STATUS BYTE 1 e s Entry End of Source Error Sweep Settled EXTENDED STATUS BYTE 2 aes a ST a a eee re a e e yos l ek ee Not External 0 FM Over Self Phase Ref always modulated Test Locked Failed Panel Entry Complete Figure 3 11 Status Byte Information Sending the Status Bit Message cont d bit true The Signal Generator can send the Status Bit message without being addressed to talk The data line that the Signal Generator is assigned to respond on can be cleared by turning the instrument to STBY or by sending the Parallel Poll Unconfigure PPU bus command 3 45 Receiving th
322. y to 6 0 GHz and frequency increment to 500 MHz FUNCTION DATA UNITS c OOO A OOO Frequencies may be entered in GHz MHz or kHz but are always displayed in MHz To change the current frequency by the selected increment value use FREQ INCREMENT HP 8673H Operation SETTING THE OUTPUT LEVEL The output level is set with the RANGE and VERNIER controls ALC INTERNAL First press to maintain output power at a constant level RANGE Then press 2 lt a to step the output level down or up by increments of 10 dB The selected range is shown in the RANGE dB display MTR Then press LVL to select OUTPUT LEVEL VERNIER to be displayed on the meter VERNIER Adjust between 10 and 3 dBm as read on the meter The output level is determined by adding the meter dBm display to the RANGE dB display AUTO Enable c to ON to maximize power at the output frequency minimize power of spurious signals and optimize pulse shape for pulse modulation STORE RECALL Up to nine front panel settings can be stored for later use All Signal Generator front panel functions can be stored although OUTPUT LEVEL VERNIER is stored in remote mode only SHIFT STO O 3 stores a front panel setting in register 3 recalls a front panel setting stored in register 4 and changes the output of the Signal Generator to the recalled parameters MODULATION Three types of modulation are available amplitude AM

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