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HP Calculator 8656A User's Manual

1. 6 36 3 7 Rear Panel Features sana 3 12 6 3 Rear Panel Parts Identification 6 37 3 8 Test Setup for Basic Functional Checks 3 13 6 4 Top Internal View Top 3 9 FM Functional Check Waveform 3 16 Cover Removal 200s ree ene ene es 6 38 3 10 Data Message Examples o o 3 26 6 5 Top Internal View A3 Assembly in 3 11 Frequency Switching Characteristics 3 31 Service Position aaa 6 39 Port 6 6 Bottom Internal View A10 A11 4 1 Spurious Signals Test Setup 44 Assemblies in Service Position 6 40 4 2 Modulation Analyzer Residual AM 6 7 Bottom Internal View Bottom Cover Verification Test Setup ci dra LOG 4 5 IA AN LATA 6 41 4 3 Residual AM Test Setup aaahh Sa 4 6 6 8 Low Frequency Loop Assembly A3 4 4 Residual FM Test Setups iii kaaa iy cote 4 7 Pars dent Deaton salt nano ANT ban 6 42 4 5 High Level Accuracy and Flatness Test 6 9 Attenuator Assembly A9 Setup ee 48 Parts Identification 6 43 4 6 Low Level Accuracy Test Setup 4 12 wee Mo anon Ten L N aie 7 1 Address Buffering and Decoding Serial 1 0 4 8 Modulation Analyzer Incidental AM 3 i p and Control Schematic Diagram Verification Test Setup 0 o 4 19 P O Change O 7 5 4 9 Output Leakage Test Setup AA IO AO 5 1 5 4 Vde Power Supply Adjustment Setup 5 3 8 1 Recommended Position for Mai
2. Related HP iB interface Applicable Response Commands ner Message Controlg Functions TO L2 AH1 SHO Data Ali front panel functions except for DISPLAY DIS PLAY in conjunction with SEQ Backspace COARSE TUNE FINE TUNE and display HP 1B ADRS are programmable The front panel ADRS annunciator lights when the Signal Generator is addressed to listen Trigger The Signal Generator does not have a Device Trigger DTO capability Yes GET DTO Resets the Signal Generator to a carrier frequency of DCI 100 MHz an output amplitude of 127 dBm and no modulation Responds equally to Device Clear DCL and Selected Device Clear SDC bus commands DCL SDC Remote operation i is entered when the Remote Enable REN bus control line is true and the Signal Genera tor is first addressed to listen The front panel RMT and ADRS annunciators will both light when remote operation is entered all front panel keys will be dis abled except for the LOCAL key and the RESET STBY ON sprek and the ne ma wild remain unchanged de The Signal Generator will return to local operation GTL RLI full front panel control when either the Go to Local GTL bus command is received or the front panel LOCAL key is pressed The output signal will remain unchanged Disables the front panel LOCAL key so that only the LLO RL1 controller can return the Signal Generator to l
3. oooooomomo 8 10 Manual Updating Manual Changes SUPP OMOND ccd va oe haan WADA YES dhan 8 10 Etched Circuits Printed Circuit Boards 8 10 MOS and CMOS Integrated Circuit Replacement 0 0 005 NERE 8 10 Retrofitting Option 001 aaa 8 10 Schematic Symbology and Operating Principles R R EE ARN 8 10 Schematic Diagram Notes 0 00 8 10 Basic Logic Symbology 0 00 cece eee 8 10 Gates and QualifiersS oooooom 8 11 Indicator Symbols ooooomommmo o o 8 11 Contiguous Blockss 3 KaRa ha GAL ee daa 8 11 Dependency Notation a 8 11 Common Control Block 00 00 0400 8 15 Complex Device Symbology 8 16 Shift Register iha ANAN ova BAD Gawa KN ead 8 16 AND OR Selector aaa 8 16 Up Down Counter aaa bka Ga AG 8 16 Quad D Type Latch aa 8 16 Complex Logic Symbology and Operating Principles oooomo 8 17 Microprocessor x Kae DN Ahh aa ARA 8 17 Random Access Memory 0000 000 8 17 Read Only Memory cc cece cuees 8 17 Multiple Bus Transceivers 8 18 General Purpose Interface Adapter GPU Yc eid ae ee are dar 8 18 Successive Approximation Register SAR 8 19 Digital to Analog Converter DAC 8 19 Programmable Interval Timer 8 20 BCD to Seven Segment Latch Decoder Driver 0 0 ccc eee 8 20 Linear Device Operati
4. Model 8656A Contents CONTENTS Page Page Section Local Operation iw oss tia DA 3 1 GENERAL INFORMATION Simplified Front Panel Features 3 1 INITOD 5 55 100 REE RER Ta DAA nana LANG tada 1 1 Simplified Operation anan senses 3 1 Shecifications e ahahaha sd 1 1 General Operating Instructions 3 1 Safety Considerations SEE EEA h 1 1 Detailed Patel Features a AA AT NO LO a Instruments Covered by this Manual 1 1 Petalled Operating Aga ANG LIFE ERA BAS sa Description 1 2 Remote OPEN naaa 3 1 Carrier Frequency pisan ira 1 2 Operator s Checks Re OO sl Output Amplitude ui NANA NGANGA na GRAN 1 2 basic hb Ancona o a Modulation Capabilities 0ds 1 2 HPS I unctional Checka aasa naron at OP LONG Keke nA oe da war 1 2 Operator s Maintenance Fe ot Electrical Options scccscccccnasesees 1 3 General Operating Instructions 3 1 Mechanical Options 4 2a aaah KANYA 1 3 Power On 3 TOCOUUTE Kaman seve eee ort karaan o Rear Panel Inputs and Outputs Option 002 1 3 Power On Sequence aaa nanan sans 3 1 Front Handle Kit Option 907 u o sa 1 3 Keystroke Sequences nesre ieicoresce nin ans 3 1 Rack Flange Kit Option 908 a 1 3 Carrier Keystroke Sequence aaaunauvasaner 3 1 Rack Flange and Front Handle Combination Modulation Keystroke Sequence 3 4 Kit Option 909 ener 1 3 Store Recall Display Keystroke Sequence 3 4 Hewle
5. Model 8656A d Reinstall the bottom cover by reversing the procedure given in step a e To confirm the HP IB address simply press and hold the front panel HP IB ADRS key The internally set decimal HP IB address will be dis played in the MODULATION Display as long as the HP IB ADRS key remains pressed 2 9 Interconnection Interconnection data for the Hewlett Packard Interface Bus is provided in Figure 2 5 2 10 Mating Connectors Coaxial Connectors Coaxial mating connectors used with the Signal Generator should be either 50 ohm BNC male connectors or 50 ohm Type N male connectors that are compatible with those specified in US MIL C 39012 interface Connector HP IB mating connector is shown in Figure 2 5 Note that the two securing screws are metric 2 11 Operating Environment The operating environment should be within the following limitations Temperature waa Pha 0 C to 55 C Humidity kanang teen ees lt 95 relative at 40 C Atado nA NA maka 24570 metres 15 000 feet 2 12 Bench Operation The instrument cabinet has plastic feet and fold away tilt stands for convenience in bench opera tion The plastic feet are shaped to ensure self alignment of instruments when they are stacked The tilt stands raise the front of the Signal Gener ator for easier viewing of the front panel 2 13 Rack Mounting WARNING The Signal Generator weighs 18 1 kg 40 lb therefore care must be exercised whe
6. 8 11 3 10 Commonly Used Code Conversions 3 30 8 3 Schematic Diagram Notes ssan 8 23 Model 8656A Contents SERVICE SHEETS Section or Assembly Schematic aaa Section or Assembly Schematic Bs Overall Troubleshooting BD1 A6 Output Assembly High Frequency and Output Output Section 4 BD2 Section BD2 Heterodyne and Output Control 5 BD2 Low Frequency and FM Section BD3 Reverse Power Protection 7 BD2 Microprocessor Keyboard and A7 RFI Assembly 4 5 14 Display Section oe BD4 A8 Frequency Multiplier Assembly 3 BD2 A9 Attenuator Assembly 7 BD2 A10 Audio Power Supply Assembly A1 Keyboard Assembly 18 BD4 Modulation and RF Amplitude A2 Display Assembly Control 6 BD2 Keyboard and Encoding 18 BD4 Attenuator Control 7 BD2 Display Control 19 BD4 Frequency Modulation Control 12 BD3 Frequency Display 20 BD4 5 Power Supply 22 BD1 Amplitude Modulation and A11 Microprocessor Memory Annunciator Displays 21 BD4 HP IB Assembly A3 Low Frequency Loop Assembly Microprocessor Interrupt Process Voltage Controlled Oscillator ing and Restart 14 BD4 VCO 8 BD3 Address Buffering and Decoding Data and Timing Control 9 BD3 Serial I O and Control 15 BD4 Phase Locked Circuits 10 BD3 Memory 16 BD4 Frequency Modulation Calibrator 11 BD3 HP IB Interface 17 BD4 Frequency Modulation System i2 BD3 A12 Voltage Regulator Assembly 22 BD1 50 MHz Reference Oscillator and A13 HP IB Connector Assembly 17 BD4 Phase Lock Loop 13 BD3 A14 Filter
7. Data messages contain the program codes that control the Signal Generator s output signal The Signal Generator s complete compatibility with HP IB is further defined by the following list of interface functions SH1 AH1 TO L2 SRO RLI1 PPO DC1 DTO and CO A more detailed explana tion of these compatibility codes can be found in the IEEE Standard 488 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 boo klet titled Improving Measurements in Engi neering and Manufacturing HP part number 5952 0058 3 19 Remote Operation Remote Capability In remote operation the front panel keys are disabled except for the RESET STBY ON switch and the LOCAL key The Sig nal Generator can only be addressed to listen When addressed to listen the Signal Generator Operation a will respond to the following messages Data Clear Remote Local Local Lockout Clear Lock out Set Local and Abort Each is discussed in detail further on in this section Local to Remote Change The Signal Generator switches to remote operation upon receipt of the Remote message The Remote message is com prised of two parts They are e Remote Enable bus control line REN set true Device listen address received once while REN is true The Signal Generator s RMT and ADRS annun ciators will both light and its output signal and all
8. S RESPONSE OPERATOR S RESPONSE Data Message NOTE This check determines whether the Signal Generator properly switches from local to remote operation switches from remote to local operation and whether the LOCAL key can return the instrument to local operation It is assumed that the Signal Generator is able to both handshake and recognize its own address Before beginning this check set the RESET STBY ON switch to RESET then back to ON to initialize the instrument Description HP 9825A HP 8835A and HPL HP 9845A BASIC Send the Remote message which sets rem 707 REMOTE 707 the Remote Enable REN bus control line true and addresses the Signal Generator to listen Verify that the Signal Generator s RMT and ADRS annunciators both light lel 707 LOCAL 707 Verify that the Signal Generator s RMT annunciator turns off and that its ADRS annunciator remains on Send the Remote message to the rem 707 REMOTE 707 Signal Generator Verify that the Signal Generator s RMT and ADRS annunciators are both on Press the LOCAL key on the front panel of the Signal Generator and verify that the RMT annunciator turns off and that the ADRS annunciator remains on Send the Local message to the Signal Generator This check determines whether or not the Signal Generator properly receives Data messages Because the Signal Generator is only a listener it can only receive Data messages but never send them It i
9. Table 1 4 presents the advantages of the alternate suggestions 1 3 General Information Model 8656A Table 1 1 Specifications 1 of 3 Electrical Characteristics Performance Limits FREQUENCY Range 100 kHz to 990 MHz Resolution 100 Hz 250 Hz SPECTRAL PURITY Spurious Signals Harmonics Non harmonics Sub harmonics lt 7 dBm output levels gt 5 kHz from carrier in CW mode Residual Modulation CW Mode AM 0 05 to 15 kHz Post Detection Noise Bandwidth 0 1 to 990 MHz FM lt 15 Hz rms 0 1 to 123 5 MHz 0 3 to 3 kHz Post c3 Hz rms 123 5 to 247 MHz Detection Noise lt 6 Hz rms 247 to 494 MHz Bandwidth lt 15 Hz rms 494 to 990 MHz FM lt 30 Hz 0 1 to 123 5 MHz 0 05 to 15 kHz Post lt 8 Hz 123 5 to 247 MHz Detection Noise lt 16 Hz 247 to 494 MHz Bandwidth lt 30 Hz 494 to 990 MHz DUTPUT Level Range 13 dBm to 127 dBm Into 50 ohms Resolution 0 1 dB Absolute Level Accuracy lt 1 5 dB Output levels of 13 dBm to 127 dBm fre quencies from 100 kHz to 990 MHz lt 1 0 dB Level Flatness Output level setting of 0 0 dBm frequen cies from 100 kHz to 990 MHz AMPLITUDE MODULATION Depth 0 to 99 Output levels of 7 dBm and below fre quencies from 100 kHz to 990 MHz 0 to 30 Output levels of 10 dBm and below fre quencies from 100 kHz to 990 MHz Resolution 1 I
10. Add 5 if 250 Hz frequency increments are used FM Distortion Total Harmonic Distortion lt 0 5 100 Hz to 99 kHz peak deviations and internal rates FM Rates Internal 400 and 1 kHz 3 External 25 Hz to 25 kHz 1 dB bandwidth ac coupled GENERAL Operating Temperature 0 to 55 C Range Power Requirements Line Voltage 100 120 220 or 240 Vac 5 10 AM depth is further limited by the Indicator Accuracy specification SFM deviation is further limited by the Indicator Accuracy specification General Information Model 8656A Table 1 1 Specifications 3 of 3 Performance Limits Conditions 48 to 66 Hz Flectrical Characteristics GENERAL Cont d Line Frequency 125VA maximum Power Dissipation Conducted and radiated interference is with in the requirements of methods CE03 and RE02 of MIL STD 461A VDE 0871 and CISPR Publication 11 Conducted and Radiated Electromagnetic Interference MIL STD 461A VDE 0871 Induced in a two turn 2 5 cm 1 inch dia meter loop held 2 5 cm 1 inch away from the front surface Net Weight 18 1 kg 40 Ib Dimensions Full Envelope Height 133 mm 5 25 in nominal NOTE For ordering cabinet accessories the Width 425 mm 16 75 in nominal module sizes are 5 1 4H 1MW 17D Depth 520 mm 20 5 in nominal Electrical Characteristics Feature
11. Generator is already plugged in set the RESET STBY ON switch to ON If the power cable is not plugged in follow these instructions Front Panel Features and Simplified Operation efore troke 7 and func nains f any ill be utput Model 86564 ed using the ry step down TUNE key Q each time ing value to fect of these d for either changed so Je displayed Model 8656A o Operation gt Table 3 3 Index of Detailed Operating Instructions Lt oe Fe NM Frequency Coarse and Fine Tune ka SEE OE Modulatior Frequency Up Down Nok PAA MASE AE a Ng i Aniplitude Hais iab Fer bing Kagat 3 Amplitude Conversion ARE a NG Ampttude Ups Down SS FG a Modulation AM SE bla pended Modulation AM Up Down sa ov HA Modulation External Source Ha KAPE NG Bie St Ka Modulation EM Z Br ee 3 52 EE The actual detailed operating instructions are arranged in alphabetical order at the end of this section Operation yyyj aaa ee Modulation Keystroke Sequence Internal exter nal or mixed AM or FM functions can be selected Modulation parameters are selected in a Source Function Data Units format The modulation source either one of the two internal modulation signals 400 Hz or 1 kHz and or a signal from an external modulation source ac coupled through the front panel connector may be selected before or after the AM depth or FM peak deviation fre quency parameters ar
12. Operation Model 8656A Increment Value Display Description This instruction details how to display the stored value of the increments which are controlled by the step up and step down keys associated with each of the four main functions Increment values for the carrier frequency output amplitude AM depth and FM peak deviation frequency can be displayed Keystroke Press and release a Function key then press and hold the INCR SET key Sequence Example Display the stored carrier frequency increment F P Increment LOCAL ro FUNCTION sa oe ot tt keystrokes FREQUENCY pan FRIS Function sl a Set sa Nag program codes Keys and Program Codes Program Codes pa KON INCR SET FREQUENCY AMPTD AM FM Indications The stored value of the increment will be displayed in the display associated with the selected function as long as the INCR SET key remains pressed Comments The initialized value of each stored increment is listed as follows Carrier Frequency 10 0000 MHz Output Amplitude 10 0 dB AM Depth 1 FM Peak Deviation Frequency 1 0 kHz The display will be restored to reflect the actual Signal Generator output when the INCR SET key is released Related Increment Value Change instructions 3 48 Model 8656A Description Keystroke Sequence Example Keys and Program Codes indications Comments Related Instructions Modulation AM This instruction details how to select amplitude modulati
13. key connector switch and display information on remote operation operator s checks and opera tor s maintenance procedures 3 2 Operating Characteristics Table 3 2 briefly summarizes the major operating characteristics of the Signal Generator This table is not intended to be an in depth listing of all char acteristics For more detailed information on the Signal Generator s characteristics refer to Table 1 1 Specifications and Table 1 2 Supplemental Characteristics For information on the instru ment s HP IB capabilities refer to the summary contained in Table 3 4 HP IB Message Reference Table 3 3 Local Operation Information covering front panel operation of the Signal Generator is presented in five areas of this section namely Simplified Front Panel Features Simplified Operation General Operating Instruc tions Detailed Panel Features and Detailed Oper ating Instructions Simplified Front Panel Features Figure 3 1 on the backside of this foldout illustrates the front panel of the Signal Generator and provides simplified descriptions of each key connector switch and display In addition references are provided to the more detailed descriptions Simplified Operation The instructions on the back side of this foldout provide a quick introduction to front panel operation of the Signal Generator These instructions are designed to rapidly acquaint the novice user with the basic operation of the instr
14. 006 6 06 F 01 000 110 196 70 46 00 000 131 007 AT 07 G 01 000 111 107 71 47 00 001 000 010 8 08 H 01 001 000 110 72 4B 00 001 001 011 9 09 i 01 001 001 Hi 73 49 00 001 010 012 10 DA J 01 001 010 112 74 4A 00 001 013 013 11 0B K 01 001 011 113 75 4B 90 001 100 E 01 001 100 114 76 40 00 001 101 015 13 00 M 01 001 101 115 Y 4D 00 001 110 016 14 OE N 01 001 110 116 78 4E 00 001 111 0 01 001 111 117 79 4F 00 010 000 P 01 010 000 120 80 50 00 010 001 021 17 11 Q 01 010 001 121 81 51 00 010 010 022 18 12 R 01 010 010 122 82 52 00 010 011 S 01 010011 123 83 53 00 010 100 T 01 010 100 124 84 54 00 010 101 025 21 15 U 01 010 101 125 85 55 00 010 110 026 22 16 V 01 010 110 126 86 56 00 010 111 W 01010111 127 87 57 00 011 000 X 01 011 000 130 88 58 00011001 031 25 19 Y 01 011 001 131 89 59 00 011 010 032 26 1A Z 01011 010 132 90 SA 00 014 011 i 01011011 133 91 58 00 011 100 01 011 100 134 92 5C 00 011 101 035 29 10 01 011 101 135 33 5D 00 011 110 036 30 TE A 01 011 110 136 34 5E OG 011 144 na 01 011 111 137 95 5F 00 100 000 x 01 100 000 140 96 60 OG 100 001 041 33 21 a 01 100 001 141 97 61 00 100 010 042 34 22 b 01 100 010 142 98 62 00 100 011 c 01 100 011 143 99 63 00 100 100 d 01 100 100 144 100 64 00 100 101 045 37 25 e 01 100 101 145 101 65 00 100 110 046 38 26 f 01 100 110 146 102 66 00 100 111 G 01 100 111 147 103 67 00 101 000 h 01 101 000 150 104 68 00 101 001 051 41 29 i 01 101 001 151 105 69 00 101 010 052 42 2A j 01 101 016 152 106 6
15. 00V to 0 100 av Resolution 0 1 dB Press and release the AMPTD Function key the desired Data keys and a valid Units key or combination of valid Units keys Set the output amplitude to 12 3 dBm LOCAL aa FUNCTION comm aa a NELS mm keystrokes EN 2 E 3 AP 12 3DM TL d Data Set the output amplitude to 2 0 dB EMF uv eo FUNCTION mm aman ata am OOOO BEG AP 2 0DBEMUV FO Units Data program codes LOCAL keystrokes The selected output amplitude with sign and units will be displayed in the AMPLI TUDE Display Digits selected beyond the specified resolution of the AMPLITUDE Display will be ignored Model 8656A Model 8656A Comments Cont d Related instructions Operation Amplitude Cont d Leading zeros will be blanked Calibrated level is from 127 dBm to 13 dBm with overrange to the maximum power of the instrument Minus sign may be entered at any time before the final terminator Amplitude Data entries that would cause the peak envelope power of the instrument to exceed 17 dBm are rejected Amplitude function will remain selected until a One of the three remaining functions is selected b One of the STORE RECALL DISPLAY keys is pressed c The instrument is reset or unplugged Fourteen valid units entries are possible They are as follows dBm AB uV V EMF mV dBf dB EMF V mV EMF uV dBV dBAMFmV uV dB mV dB EMF uV EMF
16. 1801A 1820C Satisfies all requirements for testing 1814 the Signal Generator Also has in creased vertical sensitivity 0 05 mV div and a Persistance Display that makes it possible to troubleshoot the Low Freguency Loop circuits HP 8568A HP 8558B P 181T or HP 8554B 8552B 141T HP IB is Hewlett Packard s implementation of 1E EE Standard 488 and the identical ANSI Standard MCL 1 HP 9835A 98332A 98034A CRT Display HP Enhanced BASIC Larger Memory HP IB Compatible Satisfies most of the requirements for testing the Signal Generator The ex ception is the Low Level Accuracy test In this case the spectrum analyzer s noise level is high enough that the measurements are meaningless Spectrum Analyzer RF 1 10 Model 8656A Installation SECTION Il INSTALLATION 2 1 INTRODUCTION This section provides the information needed to install the Signal Generator Included is informa tion pertinent to initial inspection power require ments line voltage and fuse selection power cables time base selection HP IB address selec tion interconnection mating connectors operat ing environment instrument mounting storage and shipment 2 2 INITIAL INSPECTION WARNING 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 and panels Inspect the shipping con
17. ACCESSORIES SUPPLIED The accessories supplied with the Signal Genera tor are shown in Figure 1 1 The power cable and fuse supplied are selected at the factory according to the Mains voltage available in the country of destination For the part numbers of the power cables and Mains plugs available refer to para graph 2 6 Power Cables For the part numbers and ratings of the fuses available refer to para graph 2 5 Line Voltage and Fuse Selection If the Signal Generator is equipped with Option 001 a coaxial time base cable is supplied This cable must be connected between the rear panel TIME BASE HIGH STABILITY OPTION connector and the TIME BASE INPUT connector 1 16 RECOMMENDED TEST EQUIPMENT Table 1 3 lists the test equipment required for test ing adjusting and servicing the Signal Genera tor The Critical Specifications column describes the essential requirements for each piece of test equipment Other equipment can be substituted if it meets or exceeds these critical specifications The Recommended Model column may suggest more than one model The first model listed is usually the least expensive single purpose model Alternate models are suggested for additional fea tures that would make them a better choice in some applications For example reasons for recom mending an alternate model might be HP IB programmablility e Multi function capability that is one model can replace two or more single purpose models
18. ALC the switching time is typically 1 to 25 ms The step attenuator switching time is on the order of 12 ms Total time requirements for simple amplitude inputs or changes that is minimal software and hardware execution time is 150 ms A more com plex change may take up to 560 ms Modulation Switching There are applications where it is necessary to turn modulation on or off or to change to another modulation level It takes about 400 ms for the modulation accuracy AM or FM to be within tolerance from the time the modu lation audio oscillator is initially turned on An FM deviation change typically occurs 60 ms after the final terminator Units key triggers the change Turning the FM off will take about 20 ms Amplitude modulation normally takes about 120 ms to turn off or to change to a new depth Soft ware execution time in the modulation mode is insignificant Ja 1 RECEIVE FREQUENCY CHANGE COMMAND lt 2 EXECUTION OF FREQUENCY CHANGE BEGINS FREQUENCY ERROR yl 3 END OF HIGH SLEW RATE MODE ed 4 END OF LOW SLEW RATE MODE e 5 END OF FM CALIBRATION CYCLE Figure 3 11 Frequency Switching Characteristics 3 31 Operation Description Keysiroke Sequence Examples Keys and Program Codes ECT ee Ka E Indications Comments 3 32 Amplitude This instruction details how to set the output amplitude Operating Characteristics Range 13 dBm to 127 dBm 1
19. FM peak deviation frequency The HI EXT annunciator will light if the external modulation signal is greater than 1 02 Vpk 0 721 Vrms and the LO EXT annunciator light ifthe signal is less than 0 98 V pk 0 693 Vrms Both annunciators will be off when the input levelis 1 00 0 02 Vpk 0 707 0 014 Vrms Remote Annunciators Two LED annunciators are used to display remote operation status The RMT annunciator lights when the instrument is in remote operation The ADRS annunciator ights when the instrument has been addressed to listen via the bus regardless of whether or not the instrument is in remote operation LOCAL Key The LOCAL key returns the instrument to local operation full front panel control from remote operation provided that it is not in Local Lockout HP IB ADRS Key The HP IB ADRS key is used to display the internally set decimal HP IB address in the MODULATION Display Figure 3 2 Display and Remote Features 2 of 2 3 6 Model 8656A Operation CARRIER Keys ang The FREQUENCY key is one of the four main function keys Itis used in conjunction with FREQUENCY the numeric entry keys decimal point key and UNITS entry keys to enter carrier fre quency parameters In addition it is used in conjunction with the INCR SET key to enter carrier frequency increment values The step up and step down keys associated with the frequency function permit the carrier frequency to be changed by the value stored in the inte
20. Individual 8 15 Adjustment Setup 745 snu es NGA G 5 17 8 15 Quad D Type Latch Combined 8 16 Model 8656A LIST OF ILLUSTRATIONS Cont d Figure Page 8 16 Shift Register sonic Sawasdee ass 8 16 8 17 AND OR Selector 00 cece cece tere recs 8 16 8 18 Up Down Counter ooooocoonoronoo 8 17 8 19 Quad D Type Latch oooooooooomo os 8 17 8 20 Random Access Memory 000000 8 17 8 21 Read Only Memory 000 cee eee eee 8 18 8 22 Multiple Bus Transceiver With 3 State AG weed Sot Oe eis Sock NAN NAG 8 18 8 23 General Purpose Interface Adapter GPIA EEE a SA 8 19 8 24 Successive Approximation Register SAR cia ma Aang agb che atan are a On bang ha ayain 8 20 8 25 Digital to Analog Converter 83 bit 8 20 8 26 Programmable Interval Timer 8 21 8 27 BCD to Seven Segment Latch Decoder Driver a 8 21 8 28 Non Inverting Amplifer Gain 1 8 22 8 29 Non Inverting Amplifier Gain 1 RRO sia aa 8 22 8 30 Inverting Amplifier Gain R7 R9 8 22 8 31 Non Inverting Comparator 8 22 8 32 Inverting Comparator sasa 8 22 8 33 Overall Block Diagram 00 8 35 8 34 High Frequency and Output Section Block Diagram sd 8 37 8 35 Low Frequency and FM Section Block Diagram ie ee Gs dy pok 8 39 8 36 Microprocessor Keyboard amp Display Section Block BG ARA 8 41 8 37 Hi
21. Model 8656A Operation Amplitude Conversion Cont d Comments Linear Data entries V mV or uV will be displayed in the three most significant digits Cont d ofthe AMPLITUDE Display and the linear terminator will be autoranged or adjusted to comply with this condition Conversion formulas used are as follows dBm dBm dBf dBm 120 0 dB V dBm 13 0 dB mY dBm 47 0 dBuV dBm 107 0 dBEMFV dBm 7 0 dBEMF mV dBm 53 0 dBEMF Y dBm 113 0 V 0 Bm 13 0 20 mV 10 dBm 4 47 0 20 uV 10 4Bm 107 0 20 EMFV 10 dBm 7 0 20 EMF mV 10 dBm 53 0 20 EMF V 10 4Bm 113 0 20 Related Amplitude Instructions Amplitude Up Down 3 35 Operation Model 8656A Amplitude Up Down Description This instruction details how to change the output amplitude by the value stored in the internal output amplitude increment register Keystroke Press and release the step up or step down keys associated with the output amplitude Sequence function Keys and Program Codes Program Codes A p Aoba Ht ey va Be rey Stroud NOTE During remote operation repeated UP or DN codes can be sent over the bus once the frequency function has been selected Indications The output amplitude shown in the AMPLITUDE Display and the output of the Signal Generator will change by the value stored in the internal output amplitude increment register Comments Step up and step down keys associated with the outp
22. counter 3 14 Model 8656A Operation OPERATOR S CHECKS 3 15 Basic Functional Checks Cont d Continue to increase the carrier frequency to the maximum value listed in the following table Carrier Frequency MHz 111 1111 222 2222 333 3333 444 4444 555 5555 666 6666 TTI EU 888 8888 Verify that the FREQUENCY Display on the Signal Generator agrees with the frequency displayed on the frequency counter each time the carrier frequency is increased 7 Quickly press and release the frequency step down key to decrease the carrier frequency Verify that the FREQUENCY Display on the Signal Generator agrees with the frequency displayed on the frequency counter Continue to decrease the carrier frequency to the minimum value listed in the previous table Verify that the FREQUENCY Display on the Signal Generator agrees with the frequency displayed on the frequency counter each time the carrier frequency is decreased Output Level Checks 8 Connect the RF OUTPUT of the Signal Generator to the input of the spectrum analyzer as shown in Figure 3 8 9 Set the output amplitude of the Signal Generator to 0 0 dBm carrier frequency to 0 1 MHz and frequency increment value to 10 MHz 10 Set the amplitude scale of the spectrum analyzer to display 1 dB division and make the necessary adjustments to properly display the output signal from the Signal Generator NOTE This check only verifies level flatness it does not
23. signal should be a sine wave with a period of 2 5 ms 400 Hz 24 Press the INT 1 kHz key to change the frequency of the internal modulation source from 400 Hz to I kHz The displayed demodulated signal should be a sine wave with a period of 1 ms 1 kHz 3 16 HP IB Functional Checks lt 2 DESCRIPTION The following procedures check the Signal Generator s ability to recognize its own HP IB listen address properly make remote local transitions and process all of the applicable HP IB messages described in Table 3 4 During the process all of the Signal Generator s HP IB data input output bus control and handshake lines are checked except for DIO8 the most significant data input output bus line which is not used by the Signal Generator Only the Signal Generator a bus controller and an HP IB interface with appropriate cabling are required to perform these procedures These checks are intended to be as independent of one another as possible since each begins with the instrument being reset to its initialized condition Nevertheless itis suggested that the first four checks be performed in order before any other check Any special initialization steps or requirements for a given check are provided the beginning of the check The validity of these checks is based on the following assumptions e The Signal Generator performs properly when operated via the front panel keys that is in local operation This can be verified by
24. the necessary information to program virtually all of the instrument functions available in local operation The only exceptions are DISPLAY DISPLAY in conjunction with SEQ Backspace COARSE TUNE FINE TUNE and display HP IB ADRS Characters EQUIVALENT DECIMAL EQUIVALENT ASCII VALUE CHARACTER LISTEN LISTEN 0 1 2 3 4 5 6 7 8 9 Vii Awe Indicates Factory set address 3 23 Receiving the Data Message The Signal Generator must be in remote operation and addressed to listen before it can respond to Data messages The instrument will remain ad dressed to listen until it receives an Abort message or a universal unlisten command from the controller The paragraph entitled Switching Characteristics shows how the Signal Generator responds to Data Messages Timing considerations and other char acteristics pertinent to operation are included Data Message Input Format Data messages con tain the controller s talk address the Signal Gen 3 25 Operation Receiving the Data Message Cont d erator s listen address a string of program codes and an End of String message EOS The string of program codes follows the same protocol as a front panel keystroke sequence in local operation The EOS message can be a Line Feed LF a bus END message HOI and ATN bus control lines both set true or an internally produced KOS The following paragraphs explain other key ele ments of the program code
25. verify absolute level accuracy 11 Slowly increase the carrier frequency through its entire frequency range 0 1 to 990 0000 MHz and observe the level displayed on the spectrum analyzer The level should not vary more than a total of 3 dB 41 5 dB from 0 0 dBm 3 15 Operation O KO a aaaa Model 8656A OPERATOR S CHECKS 3 15 Basic Functional Checks Contd 12 Set the carrier frequency of the Signal Generator to 600 MHz output amplitude to 13 dBm and output amplitude increment value to 1 0 dB 13 Adjust the spectrum analyzer as necessary to display the output signal from the Signal Generator The displayed carrier should be positioned in the center of the graticule with its maximum level positioned near the top of the graticule 14 Slowly decrease the output amplitude down to 4 0 dBm and observe the level displayed on the spectrum analyzer The level should decrease in relatively uniform 1 dB steps 15 Set the output amplitude of the Signal Generator to 10 0 dBm and the output amplitude increment value to 5 dB Leave the carrier freqeuency set to 600 MHz 16 Set the amplitude scale of the spectrum analyzer to display 10 dB division and make the necessary adjustments to properly display the output signal from the Signal Generator The displayed carrier should be positioned in the center of the graticule with its maximum level positioned near the top of the graticule 17 Slowly decrease the out
26. 0 kHz are possible 1 9 OPTIONS The following options are available and may have been ordered and received with the Signal Genera tor If they were not received with the original shipment and are now desired except for option Model 8656A OPTIONS Cont d 002 they may be ordered from your nearest Hewlett Packard office using the part number included in each of the following paragraphs 1 10 Electrical Options Option 001 provides a 10 MHz crystal reference for increased frequency accuracy and stability Order HP part number 08656 60079 1 11 Mechanical Options The mechanical options except Option 002 are shown in Figure 1 1 Rear Panel Inputs and Outputs Option 002 RF Out put and Modulation Input Output Connectors are located on the rear panel The SEQ sequencing input is eliminated Front Handle Kit Option 907 Ease of handling is increased with the front panel handles Order HP part number 5061 0089 Rack Flange Kit Option 908 This kit contains all necessary hardware and installation instructions for mounting the Signal Generator in a rack with 482 5 millimeter standard 19 inch spacing Order HP part number 5061 0077 Rack Flange and Front Handie Combination Kit Option 909 This kit is not simply a front handle kit and rack flange kit packaged together The com bination is made up of unique parts which include both functions Order HP part number 5061 0083 1 12 HEWLETT PACKARD INTERFACE BUS 1 1
27. 0V Slo Blo for 220 240 Vac operation Ordering information is presented in Section II Installation Line Power Module Permits operation from 100 120 220 or 240 Vac The number visible in the window indicates nominal line voltage to which the instrument must be connected see Figure 2 1 Center conductor is safety earth ground Serial Number Plate First four digits and letter constitute the prefix which defines the instrument configuration The last five digits form a sequential suffix that is unique to each instrument The plate also indicates any options supplied with the instrument TIME BASE OUTPUT Female BNC connector J4 provides access to an internal 10 MHz time base reference output at a level greater than 0 2 Vrms into 50 ohms which is derived from the internal reference oscillator An internal jumper may be repositioned to select either a 1 or 5 MHz reference output refer to paragraph 2 7 Figure 3 7 Rear Panel Features 3 12 Model 8656A Operation OPERATOR S CHECKS EEE AGNE aan aa 3 14 OPERATOR S CHECKS Operator s checks are simple procedures designed to verify that the main functions of the Signal Generator operate properly Two procedures are provided one for basic front panel functional checks and the other for HP IB functional checks 3 15 Basic Functiona Checks DESCRIPTION This procedure requires only a frequency counter a spectrum analyzer and the inter connecting cables a
28. 3 Compatibility The Signal Generator has an HP IB interface and can be used with any HP IB computing controller or computer for automatic system applications The Signal Generator is fully programmable via the HP Interface Bus The Signal Generator s complete compatibility with HP IB is defined by the following list of interface functions SHO AH1 TO L2 SRO RL1 PPO DC1 DTO and CO The Signal Generator interfaces with the bus via open collector TTL circuitry An explanation of the com patibility codes can be found in the IEEE Stand ard 488 and the identical ANSI Standard MC1 1 For more detailed information relating to pro grammable control of the Signal Generator refer DP Not just IEEE 488 but the Kand E OEE EA per support ihat delivers the shortest path to a measurement system General Information to Remote Operation Hewlett Packard Interface Bus in Section III of this manual 1 14 Selecting the HP IB Address Five miniature HP IB address switches are located inside the Signal Generator These switches re present a five bit binary number 00 through 31 in decimal HP IB addresses greater than 30 deci mal are invalid When the instrument is shipped from the factory the HP IB address is preset to 07 decimal To determine the Signal Generator s HP IB address refer to HP IB Address Display in Section HI of this manual To change the HP IB address refer to paragraph 2 8 HP IB Address Selection 1 15
29. 50 Model 8656A Modulation AM Up Down This instruction details how to change the percentage of AM depth by the value stored in the internal AM depth increment register Press and release the step up or step down keys associated with the amplitude modula tion function Program Codes NOTE During remote operation repeated UP or DN codes can be sent over the bus once the AM function has been selected The percentage of AM depth shown in the MODULATION Display and the output of the Signal Generator will change by the value stored in the internal AM depth incre ment register Step up and step down keys associated with the amplitude modulation function are used to change the percentage of AM depth by the value stored in the internal AM depth increment register Places the instrument in the AM Data entry mode and clears any previously selected function Selects default modulation source internal 1 kHz if no other source is selected Continues to change the percentage of AM depth by the value stored in the internal AM depth increment register if either key remains pressed Will automatically stop incrementing when the maximum percentage of AM depth permitted for a selected output amplitude is reached Initialized value and limits of the AM depth increment are as follows initialized Minimum Maximum Value Value Value 1 1 lt 99 Increment Value Change Increment Value Display Model 8656A Description Key
30. 50 MHz reference oscillator or an external source that operates at 1 5 or 10 MHz An optional 10 MHz crystal reference is available for increased accuracy and stability 1 7 Output Amplitude The Signal Generator has precise power levels from 13 to 127 dBm 1 00V to 0 100 pV with overrange at decreased accuracy The output ampli tude from 13 to 127 dBm is accurate to less than or equal to 1 5 dB from 100 kHz to 990 MHz Level flatness is less than or equal to 41 0 dB with an output amplitude setting of 0 0 dBm Output ampli tude resolution is 0 1 dB A 3 1 2 digit LED dis play of output amplitude is provided with 7 LED annunciators used to display unit information Easy conversion of units between dBm uV EMF and so forth is possible 1 8 Modulation Capabilities The Signal Generator features a versatile internal and external modulation capability for AM and FM This includes internal 400 Hz or 1 kHz tones mixed modulation such as AM FM AM AM or FM FM and the capability to accept low fre quency digital unsquelching signals A 2 digit display of AM depth or FM peak deviation fre quencies is provided with 10 LED annunciators used to display internal or external modulation source information Simple keyboard entries of AM depth up to 99 with a resolution of 1 and FM peak deviation frequencies up to 99 kHz with resolutions of 100 Hz for deviations less than 10 kHz or 1 kHz for deviations greater than or equal to 1
31. A Description p Keystroke Sequences Examples Keys and Program Codes CEB indications Operation Modulation OFF This instruction details how to selectively turn off the AM or FM function In addition it details how to selectively turn off a modulation source To turn off a modulation function AM or FM press and release the associated Function key then the OFF key To turn off a modulation source press and release the associated Function key Source key then the OFF key Selectively turn off AM modulation function with only one modulation source in use same FURCTON masa ome Source maan LOCAL keystrokes OFF AMS4 program codes Function Source Selectively turn off internal 400 Hz source sme FUNCT ON mme a SOUTO mami LOCAL keystrokes a o AMS2S4 IES Fu ee program codes Sin Program Codes AM FM EXT INT 400 Hz INT 1 kHz OFF The current MODULATION Display will be blanked or the modulation source includ ing its annunciator will be turned off when the OFF key is pressed 3 59 Operatia sooo oo aa ce nano antsdbeliantsienl Comments Related Instructions 3 60 Modulation OFF Contd Currently selected modulation function AM or FM will be turned off when the OFF key is pressed provided only one source internal 400 Hz or 1 kHz or external has been selected for use If more than one source has been selected then a Sour
32. A 00 101 011 k 01 101011 153 107 68 00 101 100 i 01 101 100 154 108 6C OG 101 101 055 45 29 m 01 101 101 155 109 6D 00 101 110 056 46 2E n 01 101 110 156 110 6E 00 101 111 i Q 01 101 311 157 11 SF 0 00 110 000 060 48 30 p 01 110 000 166 112 70 1 00 110 001 061 49 31 g 01 110 001 161 113 71 2 00 110 010 062 50 32 r 01 110 010 162 114 72 3 00 110 013 063 51 33 s 01 110011 163 115 73 4 00 110 100 064 52 34 t 91 110 100 164 116 74 5 00 110 101 065 53 35 u 01 110 101 165 117 75 6 00 110 110 066 54 36 v 01110 146 166 118 76 7 00 110 111 067 55 37 wW 01 110 111 167 119 77 8 00 111 000 070 56 38 x 01 141 000 179 120 78 9 00 111 001 071 of 39 y 01311 001 174 121 79 00 111 010 072 58 3A z 01131010 172 122 7A i 00 111 011 01111011 173 123 7B 00 111 100 i 01 111 100 174 124 7 00 111 101 075 61 3D 01111101 175 125 70 00 111 140 01 111 110 176 126 TE 00 111 111 DEL 01111 111 177 127 tF 3 30 Switching Characteristics Cont d events shown in Figure 3 11 occurs every time a frequency change is made To minimize the effects of frequency hysteresis especially near the frequency band edges switch to the desired frequency from the same direction each time that is from either above or below the desired frequency Ideally the frequency change should be made from the same preset frequency The main band frequency hysteresis is 100 kHz at the main band edges that is 123 5 247 and 494 MHz During a frequency change all modulation is turned o
33. Bank Assembly 14 22 A4 High Frequency Loop Assembly A15 Line Power Module 22 BD1 IF Section 1 BD2 A16 10 MHz Reference Oscillator HF Loop Amplifier and Control 2 BD2 Assembly Option 001 13 22 BD3 A5 High Frequency Oscillator A17 Front Feedthrough Assembly 6 18 Assembly 1 BD2 19 22 ix General Information Model 86564 BER Se SEG SS ma sd AED seas FIONA GERALD Pi Sees a MODEL 8656A poe meg rm sek LINE POWER CABLE OPTION 001 OPTION 907 TIME BASE CABLE FRONT HANDLE KIT OPTION 908 OPTION 909 RACK FLANGE KIT RACK FLANGE AND FRONT HANDLE COMBINATION KIT NOTE Referto ACCESSORIES SUPPLIED f r more details Figure 1 1 HP Model 8656A Signal Generator with Option 001 and Accessories Supplied Model 8656A General Information SECTION GENERAL INFORMATION 1 1 INTRODUCTION This manual contains information required to install operate test adjust and service the Hewlett Packard Model 8656A Signal Generator The Model 8656A will generally be referred to as the Signal Generator throughout this manual Figure 1 1 shows the Signal Generator with all of its externally supplied accessories This manual also documents Signal Generators supplied with the high stability time base Option 001 and rear panel connectors Option 002 This section of the manual describes the instru ments documented by this manual and covers instrument description options accessories spec ificat
34. FM Calibrator Schematic Diagrams aaa 8 93 8 76 LF Loop FM System Control Component Locations 00a 8 95 8 77 LF Loop FM System Control and Calibrator Component Locations oooooomomo o 8 96 vili Contents Model 8656A LIST OF ILLUSTRATIONS Cont d Figure Page Figure Page 8 78 LF Loop FM System Control and Calibrator 8 94 HP IB Interface Component Locations 8 112 Block Diagrams asia 8 97 8 95 HP IB Interface Block Diagrams 8 113 8 79 LF Loop FM System Control and Calibrator 8 96 HP IB Interface Schematic Diagram 8 113 Schematic Diagram cia rs 8 97 8 97 Keyboard Component Locations 8 114 8 80 Reference Oscillator and Phase Lock Loop 8 98 Keyboard Encoder Component Locations 3464 pba hk keene eee 8 98 Component Locations 8 114 8 81 Reference Oscillator and Phase Lock Loop 8 99 Keyboard and Encoder Block Diagrams 8115 Block Diagrams s a na cane neo Sw sews Pes 8 99 8 100 Keyboard and Encoder 8 82 Reference Oscillator and Phase Lock Loop Schematic Diagram o ooooooooo 8 115 Schematic Diagram o 8 99 8 101 Display Control Component Locations 8117 8 83 A7 Assembly Interrupt Input 8 102 Display Control Block Diagrams 8 119 Component Locations cols na NAG 8 102 8 103 Display Control Schematic Diagram 8 119 8 84 Microprocessor Interrupt Processing and 8 104 Frequency Displays Restart Componen
35. HP 8656A 12 HEWLETT PACKARD 0 1 990 MHz SIGNAL GENERATOR PERAT G AND LNG AA o AA OPERATING AND SERVICE MANUAL 8656A SIGNAL GENERATOR 0 1 990 MHz including Options 001 and 002 SERIAL NUMBERS This manual applies directly to instruments with serial numbers prefixed 2035A With changes described in Section VII this man ual also applies to instruments with serial num bers prefixed 2032A 2027A 2026A 2025A 2024A 2023A 2022A 2018A 2014A and 2009A For additional important information about serial numbers see INSTRUMENTS COVERED BY MANUAL in Section I Valuetronics International Inc 1 800 552 8258 MASTER COPY Y HEWLETT PACKARD Copyright HEWLETT PACKARD COMPANY 1980 1981 1501 PAGE MILL ROAD PALO ALTO CALIFORNIA U S A OPERATING AND SERVICE MANUAL PART NUMBER 08656 90107 Operating Manual Part No 08656 90108 Microfiche Operating and Service Manual Pari No 08656 90109 Printed May 1981 Safety Considerations SAFETY CONSIDERATIONS GENERAL This is a Safety Class I instrument provided with terminal for protective earthing OPERATION BEFORE APPLYING POWER verify that the power transformer primary is matched to the available line voltage the correct fuse is installed and Safety Precautions are taken see the following warnings In addition note the instrument s external markings which are described under Safety Symbols WARNINGS Servici
36. Input Format 3 25 Operating Environments il 2 4 Keyboard to Program Code Correlation 3 26 Bench Oper es 9 4 Value Selectable Parameters 3 26 Rack Mounting hand erent ia 2 4 Data RENSE CS eee Storage and Shipment ccc ea eeee 2 7 Sending the Data Message NA PEST eee a aaa 3 27 Barr os Ca oe ake Kna Ta akan 9 7 Receiving the Trigger Message 3 27 Packaging ks cha KEN KA KGG 2 7 Receiving the Clear Message 3 27 Original Packaging 000 0000e 2 7 Receiving the Remote Message 3 27 Other Packaging u a 9 7 Receiving the Local Message 3 27 Receiving the Local Lockout Message 3 27 Receiving the Clear Lockout Set Section 1H Local Mesta lia aan 3 28 OPERATION Receiving the Pass Control Message 3 28 o saksen treng 3 1 Sending the Require Service Message 3 28 Operating Characteristics saa 3 1 Sending the Status Byte Message 3 28 CONTENTS Cont d Contents Page Sending the Status Bit Message 3 28 Receiving the Abort Message 3 28 Switching Characteristics 3 28 Frequency Switching wawa 3 29 Amplitude Switching sei cise AA NAKA kann 3 31 Modulation Switching oooomomoco 3 31 Detailed Operating Instructions 3 32 Ppt eis ados ob s332 Amplitude Co
37. MHz at a level greater than 0 15 Vrms into 50 ohms is accessible at the rear panel TIME BASE OUTPUT connector This output signal is derived from the internal reference oscillator frequency and is jumper selectable through an inductor lo cated inside the Signal Generator on the Low Fre quency Loop Assembly A3 When the instru ment is shipped from the factory the inductive jumper is hard wired to provide a 10 MHz time base output signal If the Option 001 or another external 10 MHz reference is applied to the rear panel TIME BASE INPUT connector only that reference frequency will be available as an output signal Also if either a 1 or 5 MHz output signal is desired the internal inductive jumper will have to be repositioned Similarly if an external 1 or 5 MHz reference input is to be applied to the rear panel TIME BASE INPUT connector the inductive jumper will have to be repositioned to the position that corresponds to the frequency of the external reference input The top cover of the Signal Gener ator will have to be removed to gain access to the time base jumper The following procedure des cribes how to change the location of the inductive jumper a Remove the top cover from the Signai Gener ator by first removing the two screws used to secure the strap handle to each side of the instru ment Next remove the front and rear caps slide the side cover in the direction of the arrow then lift the side cover away from the
38. NPUT OUTPUT connector replaces concerning the signals found at these ports HP IB Connector 24 pin female connector used to connect the Signal Generator to the Hewlett Packard Interface Bus for remote operation Connection information is pre sented in Section II Installation TIME BASE INPUT Female BNC connector J3 accepts an external 1 5 or 10 MHz 0 005 time base reference input at a level of 0 2to 0 4 Vrms into 50 ohms Internal jumper must be installed in the position that corresponds to the external time base reference input used refer to paragraph 2 7 3 TIME BASE HIGH STABILITY OPTION Female BNC connector A16J1 provides access to the optional 10 MHz time base reference output With Option 001 installed and its output connected to the TIME BASE INPUT connector through the supplied cable not shown the frequency accuracy and stabil ity of the Signal Generator will be increased The optional reference oscillator is kept at operating temperature in the STBY mode as long as the Signal Generator remains connected to Mains power seo Female BNC connector J5 accepts external contact closure from foot pedal pushbutton switch etc y E which causes the Signal Generator to sequentially Time Base Input while the MOD recall the stored contents exclusive ofincrement set tings from each of its ten internal storage registers O Fuse 1 25A 250V Slo Blo for 100 120 Vac operation 0 6A 25
39. PUT located at the rear of the Signal Generator as shown in Figure 3 8 3 13 O peration Model 8656A OPERATOR S CHECKS 3 15 Basic Functional Checks Cont d Connecting the 10 MHz reference output of the frequency counter to the TIME BASE INPUT of the Signal Generator will phase lock the two instruments to the same time base reference NOTE If the Signal Generator is equipped with the high stability time base Option 001 disconnect its cable from the TIME BASE INPUT before performing this step Frequency Check 4 Set the output amplitude of the Signal Generator to 10 0 dBm and the carrier fre quency to the values listed in the following table Carrier Frequency MHz 100 0000 140 0000 200 0000 300 0000 400 0000 600 0000 800 0000 990 0000 Verify that the FREQUENCY Display on the Signal Generator agrees with the frequency displayed on the frequency counter except for the resolution of the fre quency counter being used 5 Set the carrier frequency of the Signal Generator to 111 1111 MHz and the frequency increment value to 111 1111 MHz Leave the output amplitude set at 10 0 dBm Verify that the FREQUENCY Display on the Signal Generator agrees with the frequency displayed on the frequency counter 6 Quickly press and release the frequency step up key to increase the carrier frequency Verify that the FREQUENCY Display on the Signal Generator agrees with the frequency displayed on the frequency
40. TION Display and the output of the Signal Generator will change by the value stored in the internal FM peak deviation frequency increment register Step up and step down keys associated with the frequency modulation function are used to change the FM peak deviation frequency by the value stored in the internal FM peak deviation frequency increment register Places the instrument in the FM Data entry mode and clears any previously selected function Selects default modulation source internal 1 kHz if no other source is selected Continues to change the FM peak deviation frequency by the value stored in the internal FM peak deviation frequency increment register if either key remains pressed Will automatically stop incrementing when the maximum FM peak deviation fre quency permitted for a selected carrier frequency is reached If an out of range condition exists MODULATION Display flashing pressing either the step up or step down or FM key will automatically select the maximum FM peak deviation frequency permitted for the currently selected carrier frequency Initialized value and limits of the FM peak deviation frequency are as follows Initialized Minimum Maximum Value Value Value 1 0 kHz 0 1 kHz lt 99 kHz Increment Value Change Increment Value Display Model 8656A Operation Modulation Mixed Description These instructions detail the selection of mixed modulation Moduiation can be selected in one of four ways 1 S
41. V Amplitude Conversion Amplitude Up Down 3 33 Operation Model 8656A Amplitude Conversion Description This instruction details how to change the AMPLITUDE Display from power units in dBm to any one of thirteen other valid unit configurations This feature does not affect the actual output amplitude of the Signal Generator Keystroke Press any valid Units key or combination of valid Units keys with the amplitude Sequence function selected Example The AMPLITUDE Display shows 10 0 dBm Change the display to units of dB V The resulting display will be 117 0 dB uV gun ABRA A AB LIV men Prefix Terminator Final Terminater LOCAL keystrokes ammen BP tn EB UV mn DBUV Prefix RP IL Final Terminator 1 Final Terminator 2 Prefix Terminator 3 Final Terminator for Increment Set Mode Indications The AMPLITUDE Display will change to reflect the newly selected units and the corresponding annunciator s will hght Comments The amplitude function must be selected before the conversion entry or entries are made Logarithmic Data entries dBm or dBf will be displayed in the AMPLITUDE Display with 0 1 dB resolution The dBm or dBf Units terminator overrides a dB or EMF terminator IfadBor EMF Units terminator is selected the AMPLITUDE Display will be blanked the corresponding annunciator will light and the Signal Generator will wait for a final terminator to be entered 3 34
42. V dB aV dB EMF V dB EMF mV dB EMF aV y mV uV EMF V EMF mV EMF aV AM entries are always terminated in and FM entries are always terminated in kHz The backspace key is used to clear the last digit or decimal point visible in a display to permit the entry to be corrected Figure 3 5 Data and Units Entry Features 3 9 Operation Model 8656A STORE RECALL DISPLAY SEQUENCE Keys Four keys used to store up to ten complete front panel setups exclusive of increment values for either selectable or sequential recall or display at a later time When the Signal Generator is powered up or reset the initialized conditions of the instrument are stored in each of the ten internal storage registers That is the parameter values for a carrier frequency of 100 MHz with an output amplitude of 127 dBm and no modulation will be stored in each location When the STORE key is used in conjunction with a numeric entry key a single digit register number 0 9 the current front panel settings exclusive of increment values will be stored in an internal storage register When the RECALL key is used in conjunction with a numeric entry key a single digit register number 0 9 the stored contents will be recalled and the output of the Signal Generator will be changed so that it agrees with the recalled parameter values When the DISPLAY key is used in conjunction with a numeric entry key a single digit register number 0 9 the stored c
43. ack to ON to initialize the instrument Deacrintion HP 9825A HP 9835A and p HPL HP 9845A BASIC rem 7 REMOTE 7 Send the first part of the Remote message which enables the Signal Generator to remote wrt 707 ap3dbmv OUTPUT 707 AP3DBMV Address the Signal Generator to listen which completes the Remote message and send the Data message which sets the output amplitude of the Signal Generator to 3 0 dB mV Verify thatthe Signal Generator s RMT ADRS dB and mV annunciators all light and that the AMPLITUDE Display shows an output amplitude of 3 0 dB mV Send the Clear message clr 707 RESET 707 Verify that the Signal Generator s RMT and ADRS annunciators remain on and that the AMPLITUDE Display now shows the initialized output amplitude of 127 0 dBm The dB and mV annunciators will now be off and the dBm annunciator will be on This check determines whether or not the Signal Generator becomes unaddressed when it receives the Abort message It is assumed that the Signal Generator is able to handshake recognize its own address and properly make remote local transitions Before beginning this check set the RESET STBY ON switch to RESET then back to ON to initialize the instrument HP 98254 HP 9835A and Geseripuion HPL HP 9845A BASIC Send the complete Remote message rem 707 REMOTE 707 Operation Model 8636A OPERATOR S CHECKS 3 16 HP iB Functionai Ch
44. ased Display Sequence Model 8656A Descrintion Keystroke Sequence Example Keys and Program Codes Indications Comments Frequency This instruction details how to set the carrier frequency Operating Characteristics Range 100 kHz to 990 MHz 990 0000 MHz Resolutions 100 Hz and 250 Hz depending on the carrier frequency selected Press and release the FREQUENCY Function key the desired Data keys and a valid Units key i Set the carrier frequency to 123 45 MHz me OCT EON am remeron Data maana maan JEG mm LOGAL posen 0660 a FR123 45MZ E EBA NG AE Data FREQUENCY MHz kHz No key The selected carrier frequency will be displayed in megahertz in the FREQUENCY Display Least significant eighth digit will be blanked when the selected carrier frequency is a multiple of 100 Hz In cases where the selected carrier frequency is a multiple of 250 Hz the least signifi cant digit will be a 5 Digits selected beyond the specified resolution of the FREQUENCY Display will be truncated Leading zeros will be blanked Carrier frequencies below 100 kHz will result in an uncalibrated output amplitude The MODULATION Display will flash if a change in carrier frequency would cause the FM peak deviation frequency allowed for that frequency band to be exceeded Entering a carrier frequency that would set the instrument in the correct band for the selected deviation frequenc
45. ation function is selected the MODULATION Display will be updated to display the newly selected parameter Selecting the other function will restore the original display If a change in carrier frequency causes the FM peak deviation frequency allowed for that frequency band to be exceeded the MODULATION Display will flash until a carrier frequency within the correct band is selected or the FM FM step up or FM step down key is pressed In this later case the maximum FM peak deviation frequency permitted for the currently selected carrier frequency will automatically be selected The MODULATION Display is also used to display the values stored in the internal AM depth and FM peak deviation frequency increment registers These stored values are used in conjunction with the step up and step down keys associated with the modulation functions to change the percentage of AM depth or FM peak deviation irequency Further the MODULATION Display is used to display the internally set decimal HP IB address HP IB addresses from 0 to 30 decimal are valid all others will be interpreted as 30 Refer to Section II Installation when changing the HP IB address Ten LED annunciators are used to display internal and external modulation source information The HI EXT and LO EXT annunciators serve as an aid in adjusting the level of the external modulation source They indicate that the input level is too high or too low for a calibrated display of AM depth or
46. ccuracy is required the signal level should be measured externally l Figure 3 4 Modulation Features 3 8 Model 8656A Operation Data Entry Keys The Data entry keys consist of ten numeric entry keys 0 9 a decimal point key and a minus sign key The ten numeric entry keys are used in conjunction with the four main function keys to enter value selectable parameters with the INCR SET key to enter increment values and with the STORE RECALL DISPLAY keys to select one of the ten internal storage registers The decimal point key is used to add a decimal point to the numeric entry A leading zero will be displayed if the decimal point is added before the numeric entry for carrier frequencies less than I MHz and output amplitudes less than 1 dBm The minus sign key is only used when making amplitude Data entries and it can be used at any time before the final UNITS terminator entry is made UNITS Entry Keys The UNITS entry keys consist of ten terminator keys and a backspace key The ten terminator keys are used in conjunction with the four main function keys to terminate Data entries They are also used in conjunction with the INCR SET key to terminate increment value entries Frequency entries are always adjusted so that they are displayed in megahertz even though kHz is a valid terminator Fourteen amplitude terminator combinations are possible They are listed as follows dBm dBf dB V dB m
47. ce key INT 400 Hz INT 1 kHz or EXT has to be pressed before the OFF key is pressed In this case the currently selected modulation function will remain selected and only the chosen source including its annunciator will be turned off If both modulation functions are simultaneously selected and share the same source then only the currently selected modulation function will be turned off when the OFF key is pressed and the MODULATION Display will be restored to show the modulation parameters of the remaining function Modulation AM Up Down Modulation FM Up Down Modulation External Source Modulation Mixed Model 8656A Model 8656A Description Keystroke Sequence Example Keys and Program Codes Indications Comments Related Instructions Operation Recall This instruction details how to selectively recall the stored contents from an internal storage register Press and release the RECALL key then a Data key a single digit register number 0 9 Recali the stored contents from register 2 LOCAL ym Recall Contents from Register 2 se keystrokes RECALL 2 RC2 a Recali Contents from Register 2 Program Codes RECALL The stored contents from the selected register will be recalled and the output of the Signal Generator will be changed so that it agrees with the recalled parameter values Ten internal registers are available 0 9 Each is capable of
48. comoomoo 5 1 Equipment Required ss 6 lees Bie ae 5 1 Factory Selected Components 5 1 Post Repair Adjustments 0 000 aaa 5 2 Related Adjustments o oooooooomcmrmmmm 5 2 Power Supply Voltage Adjustment 5 3 iv Model 8656A Page Reference Voltage Adjustment oooooomoo 5 4 Audio Oscillator Level Adjustment 5 5 AM Offset Adjustment iia 5 6 715 MHz Sideband Adjustment 0 00 005 5 7 Notch Filter Adjustments aaa 5 8 High Frequency Loop Offset Adjustment 5 11 50 MHz Reference Oscillator Frequency AUSTEN ad spades toa ees ECR has 5 13 50 MHz Reference Oscillator Level Adjustment ett Va 5 14 60 to 110 MHz Oscillator Flatness Adjustment diia 5 15 690 to 740 MHz IF Compensation Adsense 5 16 400 MHz Bandpass Filter Adjustment B 17 Level and ALC Loop Detector Adjustments 5 18 Heterodyne Band Accuracy and Flatness Adjustments ai HUK ea da ANNA 5 20 AM9 and ALC Loop AM Adjustment 5 22 FM Deviation Adjustment 0000 eee 5 24 FM Frequency Response Adjustment 5 25 Attenuator Adjustments ocooooommmmmmmoo 5 26 A 001 10 MHz Reference Oscillator Frequency Adjustment oooooooccoommoos 5 29 Section VI REPLACEABLE PARTS Introduction oen en oo cul Waa we ee 6 1 Abbreviations nana eee 6 1 Replaceable Parts List 2 cece eee eee 6 1 Factory Selected Par
49. cted function as long as the INCR SET key remains pressed The frequency coarse tune and fine tune feature will be disabled and the original carrier frequency increment value will be restored when the INCR SET key is pressed RESET STBY ON Switch Three position rocker switch used to control the operating state of the internal micropro cessor The Signal Generator and its optional reference oscillator will remain energized and the fan will continue to operate as long as the power cord is connected to Mains power When momentarily set to RESET the microprocessor will be halted Upon release the microprocessor will initiate its restart operation When set to STBY the microprocessor will initiate an RF quieting operation in which all displays are blanked the high frequency section is turned off all attenuator sections 120 dB are switched in the internal audio oscillator is turned off and the instrument will not respond to any HP IB commands When set to ON return from STBY the operating state of the instrument prior to entering the standby state will be restored Refer to paragraph 3 9 for information regarding the power on sequence Figure 3 6 Miscellaneous Features 2 of 2 3 11 Operation Model 8656A NOTE For Option 002 instruments the RF OUTPUT and MOD INPUT OUTPUT connectors are located on the rear panel The RF OUTPUT connector is above 2 SEQ Refer to Figures 3 3 and 3 4 for detailed information I
50. ction details how to select frequency modulation using the internal modulation source Operating Characteristics Peak Deviation Carrier Maximum Peak Deviation Freguency MHz Rates gt 60 Hz Rates lt 80 Hz 0 1 123 5 1600 x Rate 123 5 247 400 x Rate 247 494 800 x Rate 494 990 1600 x Rate Resolution 0 1 kHz for peak deviations lt 10 kHz 1 kHz for peak deviations 210 kHz Rate internal 400 Hz or 1 kHz 13 Keystroke Press and release an Internal Source key the FM Function key the desired Data keys Sequence and a valid Units key Example Select FM with a peak deviation frequency of 25 kHz using the internal 400 Hz source emo SOUTCE di wor Functions amme Data mm pamo Units INT er CG S2FM25KZ Source es TL hits LOCAL keystrokes Function Data INT 400 Hz INT 1 kHz FM kHz Indications Selected FM peak deviation frequency will be displayed in the MODULATION Display and the source annunciators INT FM 400 Hz and 1 kHz will light Comments Digits selected beyond the specified resolution for FM peak deviation will be truncated Leading zeros will be blanked 3 52 Model 8656A Comments Cont d Related instructions Operation Modulation FM Contd FM peak deviation Data entries that would be out of range for the selected carrier frequency are rejected The MODULATION Display will flashif a changein carrier freq
51. cy will clear the error condition or pressing one of the following keys will automatically adjust the FM peak deviation frequency to the maximum frequency possible for that frequency band Carrier Frequency 0 1 123 5 FM te Ba 123 5247 247 494 494 990 Initialized value and limits of the carrier frequency increment are as follows Initialized Minimum Maximum Value Value Value 10 0000 MHz 0 1 kHz 989 99 MHz Frequency Coarse and Fine Tune Increment Value Change Increment Value Display 3 43 Operation Description Keystroke Sequence Example Keys and Program Codes 4 Indications Comments 3 44 HP IB Address Display This instruction details how to display the internally set decimal HP IB address Press and hold the HP IB ADRS key Display the internally set decimal HP iB address em Display HP IB Address HP iB ADRS LOCAL keystrokes This feature is not accessible via HP IB HP IB ADRS The internally set decimal HP IB address will be displayed in the MODULATION Display as long as the HP IB ADRS key remains pressed HP IB addresses greater than 30 decimal are interpreted as 30 HP IB address is factory set to 07 decimal In binary this is 00111 the equivalent ASCII character is an apostrophe HP IB address is updated only when the instrument is powered up or reset To change the HP IB address refer to paragraph 2 8 HP IB Addres
52. digit display of carrier frequency from 10 kHz to 990 MHz with a resolution of 100 Hz or 250 Hz Carrier frequencies are always displayed in megahertz Any selected frequency between 10 kHz and 100 kHz will result in an uncalibrated output amplitude When the selected carrier frequency is a multiple of 100 Hz the resolution will be 100 Hz and the least significant eighth digit will be blanked In cases where the selected carrier frequency is a multiple of 250 Hz the resolution will be 250 Hz and theleast significant digit will be a 5 Digits selected beyond the specified resolution will be truncated and leading zeros will be blanked The FREQUENCY Display is also used to display the value stored in the internal carrier frequency increment register This stored value is used in conjunction with the step up and step down keys associated with the frequency function to change the carrier frequency AMPLITUDE Display The AMPLITUDE Display provides a 3 1 2 digit display of output amplitude from 17 to 127 dBm with a resolution of 0 1 dB Amplitude levels are displayed in dBm dBf V mV and uY while relative levels are displayed in dB and EMF Calibrated levels from 13 to 127 dBm are possible with overrange to the maximum available power amplitude set to 17 dBm Digits selected beyond the specified resolution will be truncated and leading zeros will be blanked The AMPLITUDE Display is also used to display the value stored in the internal outp
53. e control of the Sig nal Generator Some HP IB conditions are reset to their default state during turn on 3 21 Addressing The Signal Generator interprets the byte of infor mation on its eight data input output bus lines as either an address or a bus command whenever the bus is in the command entry mode that is when the Attention bus control line ATN is true and the Interface Clear bus control line IFC is false Whenever the Signal Generator is being addres sed whether in local or remote operation the front panel ADRS annunciator will light The Signal Generator s listen address is estab lished by five miniature rocker switches located inside the instrument The address selection pro cedure is described in Section II Installation The decimal equivalent of the listen address can be displayed in the MODULATION Display by pres sing the HP IB ADRS key Refer to Table 3 5 for a Hst of the valid decimal listen address values and their equivalent ASCII characters 3 22 Data Messages The Signal Generator communicates on the inter face bus with Data messages Each Data message consists of one or more bytes of information sent over the Signal Generator s eight data input out put bus lines DIO1 through DIO8 during the data entry mode The data entry mode is established when the Attention bus control line ATN is false Data messages include the program codes listed in Tables 3 8 and 3 9 These program codes contain
54. e its own address and properly make remote local transitions Before beginning this check set the RESET STBY ON switch to RESET then back to ON to initialize the instrument Fasos HP 9825A HP 9835A and HPL HP 8845A BASIC REMOTE 707 Send the first part of the Remote rem 707 message which enables the Signal Generator to remote Send the Local Lockout message LOCAL LOCKOUT 7 Address the Signal Generator to wrt 707 OUTPUT 707 listen which completes the Remote message OPERATOR S Verify that the Signal Generator s RMT and ADRS annunciators both light Press the RESPONSE LOCAL key on the front panel of the Signal Generator and verify that its RMT and ADRS annunciators both remain on Send the Clear Lockout Set LOCAL 7 Local message 3 20 Model 8656A Model 8656A Operation OPERATOR S CHECKS 3 16 HP IB Functional Checks Cont d OPERATOR S RESPONSE Clear Message NOTE OPERATOR S RESPONSE OPERATOR S RESPONSE Abort Message NOTE Verify that the Signal Generator s RMT annunciator is turned off and that its ADRS annunciator remains on This check determines whether or not the Signal Generator properly responds to the Clear message It is assumedthatthe Signal Generator is able to handshake recognize its own address properly make remote local transitions and receive Data messages Before beginning this check set the RESET STBY ON switch to RESET then b
55. e selected The internal 400 Hz or 1 kHz modulation source will be common to both AM and FM functions whenever they are simultaneously selected Store Recall Display Keystroke Sequence Up to ten complete front panel settings exclusive of increment values can be stored for either selecta ble or sequential recall at a later time Stored front panel settings can also be displayed without actu ally changing the output signal A two keystroke sequence is necessary to store recall or display front panel settings First the desired function is entered followed by a numeric entry 0 9 This numeric entry represents the location of the inter nal storage register 3 11 Time Base Selection The Signal Generator is shipped from the factory with an inductive jumper hard wired to provide a 10 MHz time base output signal at the rear panel TIME BASE OUTPUT connector If either a 1 or 5 MHz output signal is desired this internal induc tive jumper will have to be repositioned Also ifan external I or 5 MHz reference input is to be applied at the rear panel TIME BASE INPUT connector this internal inductive jumper will have to be repo sitioned In either case this internal inductive jumper has to be installed in the position that cor responds to the frequency of the time base input or output signal being used Refer to paragraph 2 7 for the time base selection procedure 3 12 OPERATOR S MAINTENANCE WARNING For continued pr
56. eature is disabled and the original carrier frequency increment value is enabled by pressing the INCR SET key with the frequency function selected Enable a carrier frequency tuning value of 10 kHz assuming a starting value of 10 MHz sasama Decrease Tuning Value samme LOCAL N keystrokes 18 10 10 ele f This feature is not accessible via HP IB pro Program Codes ya J Bs LE FREQUENCY COARSE TUNE FINE TUNE hp w INCR SET Whenever the COARSE TUNE or FINE TUNE key is pressed and held the frequency digit that corresponds to the carrier frequency tuning value will flash When the COARSE TUNE key is pressed again the next digit to the left will flash to indicate the new tuning value When the FINE TUNE key is pressed again the next digit to the right will flash to indicate the new tuning value Feature only applies to the carrier frequency function Feature is not accessible via HP IB 3 41 Operation Model B6BBA Frequency Coarse and Fine Tune Cont d Comments COARSE TUNE and FINE TUNE keys are always available to change the carrier Cont d frequency tuning value by a factor of 10 Places the instrument into the frequency Data entry mode and clears any previously selected function once either the step up or step down key is pressed Enables the last valid carrier frequency increment value when the INCR SET key is pressed Related Frequency instructions Frequency Up Down Increm
57. ecks Coni d OPERATOR S Verify that the Signal Generator s RMT and ADRS annunciators both light RESPONSE Send the Abort message which unaddresses the Signal Generator to ABORTIO 7 listen OPERATOR S Verify that the ADRS annunciator turns off RESPONSE NOTE The remote annunciator may also turn off when using the 9835A or 9845A 3 22 Model 8656A 3 17 REMOTE OPERATION HEWLETT PACKARD INTERFACE BUS The Signal Generator can be operated through the Hewlett Packard Interface Bus HP IB Bus com patibility programming and data formats are described in the following paragraphs All front panel functions except for DISPLAY DISPLAY in conjunction with SEQ Backspace COARSE TUNE FINE TUNE and display HP IB ADRS are programmable through HP IB A quick check of the Signal Generator s HP IB input output capability is described in paragraph 3 16 HP IB Functional Checks These checks are used to verify that the Signal Generator can respond to each of the applicable HP IB messages described in Table 3 4 3 18 HP IB Compatibility The Signal Generator has an open collector TTL HP IB interface which can be used with any HP IB computing controller or computer for auto matic system applications The Signal Generator is fully programmable via the HP Interface Bus Its programming capability is described by the twelve HP IB messages listed in Table 3 4 Fore most among these messages is the Data message
58. ed in the following areas of this section a General HP IB information begins with para graph 3 17 b A summary of HP IB capabilities is pro vided in Table 3 4 c Asummary of program codes is provided in Tables 3 8 and 3 9 d Detailed information relating to the Signal Generator s HP IB programmable features to gether with tables and examples of associated program codes are presented in the detailed oper ating instructions which are arranged alphabeti cally at the end of this section 3 5 Operator s Checks Operator s checks are simple procedures designed to verify that the main functions of the Signal 3 1 Generator operate properly Two procedures are provided one for basic front panel functional checks and the other for HP IB functional checks Basic Functionai Checks This procedure requires only a frequency counter a spectrum analyzer and the interconnecting cables and adapters It pro vides assurance that most of the front panel controlled functions are being properly executed by the Signal Generator HP IB Functional Checks This series of procedures requires only an HP IB compatible computing controller and an HP IB interface with its intercon necting cable These procedures assume that front panel operation has been previously verified that is that the basic functional checks have been previously performed The procedures check all of the applicable bus mes sages summarized in Table 3 4 3 6 Ope
59. ency band and the state of the successive approximation register of the Low Frequency Loop Therefore it is best to assume that the entire sequence of Table 3 9 HP IB Program Codes Functional Order Program Parameter Code FREQUENCY Frequency carrier AMPLITUDE Amplitude carrier MODULATION Amplitude Modulation Frequency Modulation External Modulation Source Internal 400 Hz Modulation Source internal kHz Modulation Source Modulation Source Off DATA Numerals 0 9 Minus Sign Decimal Point Program codes can be either upper or lower case Kither PC or can be used The RESET STBY ON switch must be in the ON position The source of reverse power must be removed Program Parameter Code UNITS Cont d dBm EMF Volts mV uY Hz kHz MHz Percent Percent OTHER Step Up 1 Step Down 1 Increment Set Standby On Store Recall Sequence Reverse Power Protection Reset 4 3 29 Operation Model 8656A Table 3 10 Commonly Used Code Conversions Hexa Hexa Binary Decimal decimal ASCII Binary Decimal decimal 40 00 000 000 000 00 a 01 000 000 100 00 000 001 001 01 A 01 000 001 101 i 00 000 010 002 gt 02 B 01 000 016 102 65 42 00 000 011 003 3 03 01 000 011 103 67 43 00 000 100 004 4 04 D 01 000 100 104 68 44 00 000 101 005 5 05 E 07 000 101 105 69 45 00 000 110
60. ent Value Change 3 42 Model 8656A Description Keystroke Sequence Keys and Program Codes amp indications Comments Related Instructions Operation Frequency Up Down This instruction details how to change the carrier frequency by the value stored in the internal carrier frequency increment register Press and release the step up or step down keys associated with the carrier frequency function NOTE During remote operation repeated UP hi or DN codes can be sent over the bus e a once the frequency function has been selected The carrier frequency shown in the FREQUENCY Display and the output of the Signal Generator will change by the value stored in the internal carrier frequency increment register Step up and step down keys associated with the carrier frequency function are used to change the carrier frequency by the value stored in the internal carrier frequency increment register Places the instrument in the Frequency Data entry mode and clears any previously selected function Continues to change the carrier frequency by the value stored in the internal carrier frequency increment register if either key remains pressed The MODULATION Display will flash if a change in carrier frequency would cause the FM peak deviation frequency allowed for that frequency band to be exceeded Entering a carrier frequency that would set the instrument in the correct band for the selected deviation frequen
61. er cord set Whenever it is likely that the protection has been impaired the in strument must be made inoperative and be secured against any unintended operation If this instrument is to be energized via an external autotransformer for voltage reduction make sure that the common terminal is connected to the earthed pole of the power source 2 5 Line Voltage and Fuse Selection CAUTION BEFORE PLUGGING THIS INSTRU MENT into the Mains line voltage be sure the correct voltage and fuse have been selected A rear panel line power module permits operation from 100 120 220 or 240 Vac The number visible in the window located on the module indicates the nominal line voltage to which the instrument must be connected 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 Table 2 1 lists the ratings and HP part numbers for the replaceable fuses For protection against fire hazard the line fuse should only be a 250V slow blow fuse with the correct current rating 2 1 Installation 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 firmly into the slot 3 Rotate the FUSE PULL lever to it
62. ertical Sensitivity 10 mV div Bandwidth 50 MHz Oscilloscope Power Meter and Sensor Frequency Range 100 kHz to 990 MHz HP 4364 or P A T Power Range 17 to 25 dBm with HP 8482A HP 436A Option 022 Frequency Range 10 to 990 MHz with HP 8484A and Power Range 20 to 60 dBm with HP 8484A HP 8484A see Table 1 4 Accuracy 20 2 dB Signal Source Frequency 50 to 300 MHz HP 8640B Level 20 dBm Signature Analyzer Provides perferred method for troubleshooting HP 5004A digital circuitry gt E ki Spectrum Analyzer RF Frequency Range 0 1 to 990 MHz HP 8568A or P A T Resolution Bandwidth lt 1 kHz to 3 kHz HP 8558B P 181T or see Table 1 4 Spectrum Analyzer RF Frequency 10 to 990 MHz Model 8568A PLATE Resolution Bandwidth lt 100 kHz Video Average 25 Sweeps Test Oscillator Level 0 0 to 1 Vpk into 50 and 600 ohms HP 651B P T Frequency 25 Hz to 25 MHz Wideband Amplifier Gain 20 or greater HP 8447D Option 010 Frequency Range 10 MHz to 990 MHz Impedance 50 ohms Connector Type N f Use Coaxial 1 BNC to BNC HP 1250 0080 A T Coaxial N f to BNC m HP 1250 0077 A Coaxial Nm to BNC HP 1250 0780 Probe SMC to RF Test Point HP 1250 1598 General Information Model 8656A Table 1 3 Recommended Test Equipment 3 of 3 BNC f to BNCP HP 08662 60080 P Connector UG 210 U HP 11500A P A T Type N m Connecto
63. ey the desired Sequence 2 Function key the desired Data keys and a valid Units key Then press and release the other Source key and the same Function key that was selected previously 3 55 Operation Model 8656A Modulation Mixed Cont d Select FM with a peak deviation frequency of 5 kHz using both an internal 1 kHz modulation source and an external 150 Hz modulation source an SYLIT TO on ome FUNCTION commen Data em em FEES maan NT ikuz 5 kiz KO EXT Exampie 2 LOCAL keystrokes ERE Ran TO BE T Linii Function L Data S1FM T Source program codes Function Keystroke To select three simultaneous modulation signals AM and FM using a common source Sequence 3 rate and AM or FM from a separate source press and release the Source key to provide the common AM and FM rate Then press a Function key the desired Data keys and the valid Units key Press the other Function key the desired Data keys and the valid Units key Press and release the other Source key the appropriate Function key the desired Data keys and the valid Units key Example 3 l LA Simultaneously select AM with a depth of 90 and FM with a peak deviation frequency of 25 kHz using the internal 400 Hz source and AM with a depth of 90 using an external 6 KHz modulation source we SQUECO me ee Function mme Data ma mene y 15 mam LOCAL keystrokes ae or A Units Funct
64. ff if the FM mode has been enabled This applies to FM only or mixed modulation such as FM from two sources or simultaneous AM and FM After the frequency change and FM calibra tion is completed the modulation is turned on Amplitude Switching During an RF amplitude change the final level is always approached from a lower level This means that a critical amplitude level will never be exceeded in the course of normal Signal Generator operation Software correction of amplitude with respect to frequency may cause the amplitude to be uncali brated while a frequency change occurs The soft ware correction is implemented after the final fre quency is reached Software execution time for an amplitude change varies considerably The basic unit for amplitude in the Signal Generator is dBm An input in other units requires calculations This tends to increase the software execution time considerably For example an input in dBm generally will take about 160 ms from the terminator to the end of software execution A change increment or dec rement in dB will take a little less time typically 130 ms Examples of a change with calculations involved are a preset levelin mV with a change in dB 200 ms a level and change in mV 340 ms a level in dBm and a change in mV 460 ms A 10 dB change without modulation narrowband Automatic Level Control ALC may take up to 110 ms in the vernier hardware circuits With modulation wideband
65. frame Finally lift the top cover away from the frame b Locate the time base jumper on the Low Fre quency Loop Assembly A3 see Figure 2 3 c Unsolder one end of the inductive jumper and resolder it in the position that corresponds to the desired time base output or to the external refer ence input Model 8656A 220 240V 220 240V OPERATION PLUG SEV 1011 1959 24507 TYPE 12 CABLE HP 8120 2104 PLUG NZSS 198 AS 0112 CABLE HP 8120 1369 220 240V OPERATION PLUG CEE7 VII CABLE HP 8120 1689 OPERATION PLUG NEMA 5 15P CABLE 8120 1378 PLUG CEE22 V1 CABLE HP 8420 1860 220 240V OPERATION 100 120V OPERATION i FR H Ng sun PLUG NEMA 6 15P CABLE HP 8120 0698 220 240V OPERATION 220 240V OPERATION 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 Time Base Selection Cont d d Reinstall the top cover by reversing the pro cedure given in step a e If the Signal Generator is equipped with Option 001 ensure that the coaxial time base cable A16W2 is connected between the rear panel TIME BASE HIGH STABILITY OPTION con nector and the TIME BASE INPUT connector 2 8 HP IB Address Selection lt gt The Signal Generator is strictl
66. gh Frequency Oscillator Component Locations oooooooooomm o 8 44 8 38 IF Section A4 Assembly Component Locations oooommmooooo 8 45 8 39 High Frequency Oscillator and IF Section Block Diagrams a 8 47 8 40 High Frequency Oscillator and IF Section Schematic Diagram 0 00 00000 8 47 8 41 High Frequency Loop Amplifier and Control Component Locations 8 49 8 42 High Frequency Loop Amplifier and Control Block Diagrams 1 waa labs psi DAGAN 8 51 8 43 High Frequency Loop Amplifier and Control Schematic Diagram aao 8 51 8 44 Frequency Multiplier Component Locations ooooooomomono 8 52 8 45 Frequency Muitiplier Block Diagrams 8 53 8 46 Frequency Multiplier Schematic Diagrams 8 53 8 47 Output Section A7 Assembly Component Locations 0 00 0000 8 55 8 48 Output Section A6 Assembly Component Locations oooooooomom o o 8 56 8 49 Output Section Block Diagrams 8 57 Contents Figure Page 8 50 Output Section Schematic Diagram 8 57 8 51 Heterodyne and Output Control 47 Assembly Component Locations aa 8 58 8 52 Heterodyne and Qutput Control A6 Assembly Component Locations sa 8 59 8 53 Heterodyne and Output Control Block Diagrams iii 8 61 8 54 Heterodyne and Output Control Schematic Diagrams ooomooommomoomo 8 61 8 55 Modulation and RF Ataplitude Control Comp
67. has been removed The step up and step down keys associated with the amplitude function permit the output amplitude to be changed by the value stored in the internal output amplitude increment register The value of the output amplitude increment initially stored is 10 0 dB Its minimum value is 0 1 dB 0 001 xV or 0 001 EMF V and its maximum value is lt 144 0 dB 1 57V or lt 3 15 EMF V The output amplitude will be changed once for each keystroke or repeatedly if either key remains pressed RF OUTPUT Connector Female type N connector J2 provides access to the RF output signal Specified output levels are 13 to 127 dBm 1 00V to 100 uV with a minimum resolution of 0 1 dBm Nominal impedance is 50 ohms Reverse power protection is provided up to 50W and 25 Vde Pressing the AMPTD key restores RF output signal once the source of reverse power has been removed Figure 3 3 Carrier Features 3 7 Operation Model 8656A MODULATION Keys The AM key is one of the four main function keys It is used in conjunction with the SOURCE keys numeric entry keys and UNITS entry keys to enter amplitude modulation parameters In addition it is used in conjunction with the INCR SET key to enter AM depth increment values If the FM peak deviation frequency is being displayed when the AM key is pressed the MODULATION Display will be updated to show the percentage of AM depth The default modulation source internal 1 kHz will automaticall
68. he manual are per formed with power supplied to the instrument while protective covers are removed Any adjustment maintenance and repair of the opened instrument under voltage should be avoided as much as possible and when inevitable should be carried out only by a skilled person who is aware of the hazard involved Capacitors inside the instrument may still be charged even if the instrument has been discon nected from its source of supply SAFETY SYMBOLS AN Instruction manual symbol the appa ratus will be marked with this symbol when it is necessary for the user to refer to the instruction manual in order to vrotect the apparatus against damage Indicates dangerous voltages Earth terminal sometimes used in man ual to indicate circuit common con nected to grounded chassis Je WS The WARNING sign denotes a hazard It calls attention to a procedure practice or the like which if not correctly per formed or adhered to could re sult in injury or loss of life Do not proceed beyond a WARN ING sign until the indicated con ditions are fully understood and met The CAUTION sign denotes a hazard It calls attention to an operating procedure practice or the like which if not correctly performed or adhered to could result in damage to or destruc tion of part or all of the equip ment Do not proceed beyond a CAUTION sign until the indi cated conditions are fully under stood and met 8 CAUTION
69. hrough your nearest Hewlett Packard office Its part num ber is listed on the title page of this manual Also listed on the title page of this manual below the manual part number is a Microfiche part number This number may be used to order 100 x 150 millimetre 4 x 6 inch microfilm transparen cles of this manual Each microfiche contains up to 96 photo duplicates of the manual s pages The microfiche package also includes the latest MANUAL CHANGES supplement as well as all pertinent Service Notes 1 2 SPECIFICATIONS Instrument specifications are listed in Table 1 1 These specifications are the performance stan dards or limits against which theinstrument may be tested Supplemental characteristics are listed in Table 1 2 Supplemental characteristics are not warranted specifications but are typical charac teristics 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 documenta tion must be reviewed for familiarization with safety markings and instructions before opera tion Refer to the Safety Considerations page found at the beginning of this manual for a sum mary of the safety information Safety informa tion pertinent to the task at hand thatis installa tion operation performance testing adjustment or service is found throughout this manua
70. iators will also light until the signal level of the external source has been adjusted to 1 Vpk 0 707 Vrms 25 Digits selected beyond the specified resolution for AM depth or FM peak deviation will be truncated Leading zeros will be blanked AM depth Data entries that would cause the peak envelope power of the instrument to exceed 17 dBm are rejected FM peak deviation Data entries that would be out of range for the selected carrier frequency are rejected The MODULATION Display will flashifa change in carrier frequency would cause the FM peak deviation frequency allowed for that frequency band to be exceeded Entering a carrier frequency that would set the instrument in the correct band for the selected deviation frequency will clear the error condition or pressing one of the following keys will automatically adjust the FM peak deviation frequency to the maximum frequency possible for that frequency band Band Carrier Frequency MHz 0 1 123 5 o O 247 494 494 990 AM or FM function will remain selected until a One of the three remaining functions is selected b One of the STORE RECALL DISPLAY keys is pressed c The instrument is reset or unplugged Setting the level of the external modulation source is described under Modulation External Source Modulation AM Modulation AM Up Down Modulation External Source Modulation FM Modulation FM Up Down Modulation OFF Model 8656A Model 8656
71. imultaneous AM and FM may be selected using common or separate modulation sources rate 2 Simultaneous AM or FM at two rates may be selected by using internal and external modulation sources Only one AM depth or one FM deviation can be selected 3 Three simultaneous modulation signals AM and FM using a common source rate and either AM or FM from a separate source may be selected 4 Foursimultaneous modulation signals two AM and two FM may be selected Each AM FM pair must have a common modulation source rate Only one AM depth and one FM deviation can be selected Keystroke To select simultaneous AM and FM press and release the Source key to provide the Sequence 1 desired AM rate the AM Function key the desired Data keys and the Units key Then press and release the Source key to provide the desired FM rate the FM Function key the desired Data keys and the kHz Units key The Source key need not be pressed for FMif the AM and FM rate is the same Example 1 Ron e ard Simultaneously select AM with a depth of 70 and FM with a peak deviation fre quency of 3 kHz using the internal 400 Hz source and an external 1 kHz source respectively yum Source mm Function mr Data men a Units ma LOCAL AM 7 Co C fkeystrokes ext CI 3 khz S2AM70PC or Seung L units Function Data program codes STFM3KZ EN unio Function Data Keystroke To select simultaneous AM or FM press and release the desired Source k
72. ion Data FM25KZ aa nalo Function Jl Units SIAM Source Function 3 56 Model 8656A Keystroke Sequence 4 Example 4 Operation Modulation Mixed Cont d To select four simultaneous modulation signals press and release the appropriate Source key a Function key the desired Data keys and the valid Units key Press and release the other Function key the desired Data keys and valid Units key Press and release the other Source key and then both Function keys Simultaneously select AM with a depth of 10 and FM with a peak deviation of 50 kHz using the internal 1 KHz modulation source AM and FM with the same depth and deviation as selected previously are also selected using an external 5 kHz source ye Source 4 Function mem Ja ta mm ome nits ome m OG LOCAL keystrokes S3AM10PC or Units Source Function Data PERA biggie mako pr gram codes FM5SOKZ Function f Tunis SIAM Source a E Function FM O I 3 57 Operation Keys and Program Codes Indications Comments Related instructions 3 58 Modulation Mixed Cont d Program Codes Gd AM FM EXT INT 400 Hz INT 1 kHz The last selected AM depth or FM peak deviation frequency will be displayed in the MODULATION Display and the source annunciators will light In the case where an external modulation source is used the HI EXT and LO EXT annunc
73. ion parame ters by the set increment values and store up to ten complete front panel settings exclusive of increment values for either selectable or sequen tial recall or display at a later time The two remaining dark gray colored keys located in the upper left hand corner of the front panel select local operation and display the internally set decimal HP IB address The three digital displays show the frequency of the carrier in megahertz the least significant or eighth digit will either be blanked or a numeral 5 depending on the frequency selected the output amplitude of the carrier in one of fourteen possible units and the percentage of AM depth or fre quency of FM peak deviation used to modulate the carrier In addition the FREQUENCY Display can show the value of the carrier frequency incre ment the AMPLITUDE Display can show the value of the output amplitude increment or current contents of the internal sequence counter and the MODULATION Display can show the value of the modulation increment or internally set deci mal HP IB address The 19 LED annunciators are used to indicate remote operation status internal or external mod ulation source and unit information and ampli tude unit information All of the front and rear panel features are described in detail in Figures 3 2 through 3 7 Model 8656A Model 8656A Operation PSEOUERRY 1000000 GE FREQUENCY Display The FREQUENCY Display provides an 8
74. ions and other basic information The other sections contain the following information Section il Installation provides information about initial inspection preparation for use including time base selection and HP IB address selection for remote operation and storage and shipment Section IH Operation provides information about panel features and includes operator s checks operating instructions for both local and remote operation and operator s maintenance information Section IV Performance Tests provides the infor mation required to check performance of the in strument against the critical specifications listed in Table 1 1 Section V Adjustments provides the information required to properly adjust the instrument Section VI Replaceable Parts provides ordering information for all replaceable parts and assemblies Section VII Manual Changes with the backdating information this manual applies to all instru ments as indicated on the title page Section VIH Service provides the information required to repair the instrument Two copies of the operating information are sup plied with the Signal Generator One copy isin the form of an Operating Manual The Operating Manual is simply a copy of the first three sections of the Operating and Service Manual The Operat ing Manual should stay with the instrument for use by the operator Additional copies of the Oper ating Manual may be ordered separately t
75. ive length of connecting cable for any Hewlett Packard Interface Bus system is 20 0 metres 65 6 ft Figure 2 5 Hewlett Packard Interface Bus Connections 2 6 Model 8656A Rack Mounting Cont d Rack mounting information is provided with the rack mounting kits If a kit was not ordered with the Signal Generator as an option it may be ordered through the nearest Hewlett Packard office Slide rack mount kits are discussed in the following paragraphs refer to paragraph 1 11 Mechanical Options in Section I for information and part numbers pertaining to other rack mount kits Slide rack mount kits allow the convenience of rack mounting with the flexibility of easy access The slide kits for the Signal Generator are listed below Standard Slide Kit for HP rack enclosures asaan HP 1494 0018 Standard Tilt Slide Kit for HP rack enclosures oooooommoooo HP 1494 0025 Slide Adapter Bracket Kit for Standard Slides for non HP rack enclosures HP 1494 0023 2 14 STORAGE AND SHIPMENT 2 15 Environment The instrument should be stored in a clean dry environment The following environmental lim itations apply to both storage and shipment Temperature oooomooooo o 55 C to 75 C Humidity sa oc turnduon baw TAS lt 95 relative Altitude 15 300 metres 50 000 feet 2 16 Packaging Original Packaging Containers and materials identical to those used in factory packaging are Ins
76. key Example Set a carrier frequency increment of 1 MHz game Function mma mem NETAMENT mom am ia me ame Units em LOCAL keystrokes INER FREQUENCY MHz FRISIMZ Units Data Function rogram codes prog Increment Set INCR SET FREQUENCY AMPTD AM FM MHz kHz No Key The value of the increment will appear in the display associated with the selected function as the data is entered The frequency increment is rejected if it is not a multiple of 100 Hz or 250 Hz FM peak deviation frequency increments must be selected in units of kHz only Model 8656A Operation Increment Value Change Cont d Comments The minimum allowable increment value for each of the four main functions is listed as Cont d follows Carrier Frequency 0 1 kHz Output Amplitude 0 1dB 0 01 uV 0 001 EMF uV AM Depth 1 FM Peak Deviation Frequency 0 1 kHz The maximum allowable increment value for each of the four main functions is listed as follows Carrier Frequency lt 989 99 MHz Qutput Amplitude lt 144 0 dB lt 1 57V lt 3 15 EMFV AM Depth lt 99 FM Peak Deviation Frequency lt 99 kHz All displays will be restored to reflect the actual Signal Generator output as soon as a valid increment terminator is selected Related Amplitude Up Down instructions Frequency Coarse and Fine Tune Frequency Up Down Modulation AM Up Down Modulation FM Up Down Increment Value Display 3 47
77. ks That is the Signal Generator is connected to the bus controller through the bus controller s HP IB interface via the appropriate cable HP IB Controller HP 9825A 98213A General and Extended I O ROM s HP 9835A 98332A 1 0 ROM HP 9845A 1 0 ROM HP IB Interface oo HP 98034A use revised version with HP 9835A and HP 9845A Address Recognition NOTE OPERATOR S RESPONSE OPERATOR S RESPONSE This check determines whether or not the Signal Generator recognizes when it is being addressed and when it is not It is assumed that the Signal Generator is in local operation and that it can properly handshake on the bus Before beginning this check set the RESET STBY ON switch to RESET then back to ON to initialize the instrument Dardkiniian HP 9825A HP 9B35A and p HPL HP 9845A BASIC Set the Remote Enable REN bus lei 7 LOCAL 7 control line false Send the listen address to the wrt 707 OUTPUT 707 Signal Generator Verify that the Signal Generator s RMT annunciator remains off and that its ADRS annunciator lights CU Verify that the Signal Generator s RMT and ADRS annunciators are both off Unaddress the Signal Generator by sending a different address 3 18 Model 8656A Model 8656A Operation OPERATOR S CHECKS 3 16 HP IB Functional Checks Cont d Remote and Local Messages and the LOCAL Key NOTE OPERATOR S RESPONSE OPERATOR
78. l 1 4 INSTRUMENTS COVERED BY THIS MANUAL This instrument has a two part serial number in the form 0000400000 which is stamped on the serial number plate attached to the rear of the instrument The first four digits and the letter con 11 General Information INSTRUMENTS COVERED BY THIS MANUAL Cont d stitute the serial number prefix and the last five digits form the suffix The prefix is the same for all identical instruments It changes only when a change is made to the instrument The suffix however is assigned sequentially and is different for each instrument The contents of this manual apply directly to instruments having the same serial number prefix es as listed under SERIAL NUMBERS on the title page An instrument manufactured after the printing of this manual may havea serial number prefix that is not listed on the title page This unlisted serial number prefix indicates that the instrument is dif ferent from those documented in this manual The manual for this newer instrument is accompanied by a yellow MANUAL CHANGES supplement This supplement contains change information that explains how to adapt the manual to the newer instrument In addition to change information the supple ment may contain information for correcting er rors in the manual To keep this manual as current and accurate as possible Hewlett Packard recom mends that you periodically request the latest MANUAL CHANGES supplement The su
79. ll be changed once for each keystroke or repeatedly if either key remains pressed If an out of range condition exists MODULATION Display flashing pressing either the step up step down or FM key will automatically select the maximum FM peak deviation frequency permitted for the currently selected carrier frequency SOURCE Keys The INT 400 Hz INT 1 kHz EXT and OFF keys are used to select the internal 400 Hz or 1 kHz modulation source enable an external source to be applied through the front panel MOD INPUT OUTPUT connector or disable one or all selected modulation sources The internal modulation signal is available at the MOD INPUT OUTPUT connector when either the 400 Hz or 1 kHz modulation source is selected and the external source is not selected MOD INPUT OUTPUT Connector Female BNC connector J1 accepts either an external modulation signal or a digital unsquelching signal In addition it provides access to the 400 Hz or 1 kHz modulation signal from the internal audio oscillator Source selection is provided by the four MODU LATION SOURCE keys Nominal input impedance is 600 ohms External input rates are ac coupled with 1 dB of bandwidth The input signal should be 25 Hz to 25 kHz at 1 Vpk 0 707 Vrms 5 minimum into a 600 ohm resistive load to produce calibrated AM depths or FM peak deviations The HI EXT and LO EXT annunciators provide an indication of the input level available for calibrated modulation If greater a
80. n lifting to avoid personal injury Use equipment slides when rack mounting Installation Model 8656A E PANAO men NS EET EG PAPIN RASENDE SLM AN ps LLI fm ag Y EL ud JUMPER Base Jumper Locat ime T 3 2 igure F tan 2 5 Installation Model 8656A o SIGNAL GROUND SHIELD CONNECT TO EART PIO TWISTED PAIR WITH 11 25 57 ATN AA P O TWISTED PAIR WITH 10 22 01 sro SHOULD BE GROUNDED P O TWISTED PAIR WITH 9 21 Cod rc EN P O TWISTED PAIR WITH 8 267 Ca NDAC TWISTED PAIR P O TWISTED PAIR WITH 7 15 NRFD P O TWISTED PAIR WITH 6 I Gad 6 DAV REN Ts leo DIO 8 4 DI04 pio7 Gs EI pi03 Dios 4 C7 pio DIO5 CJ p01 iSO METRIC THREAD M3 5 x 0 6 24 PIN 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 Vdc to 0 4 Vde and the false 0 state is 2 5 Vde to 5 0 Vde Programming and Output Data Format Refer to Section III 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 6 ft of connecting cable per instrument 2 The maximum accumulat
81. ncidental Phase Modulation lt 0 3 radian peak 30 AM depth and internal rates Absolute level accuracy includes allowances for detector linearity temperature flatness attenuator accuracy and measurement error 2AM depth is further limited by the Indicator Accuracy specification 1 4 Model 8656A General Information Table 1 1 Specifications 2 of 3 Performance Limits 12 4 of reading Conditions Electrical Characteristics AMPLITUDE MODULATION Cont d Indicator Accuracy Depths lt 90 and internal rates AM Rates Internal External 400 and 1 kHz 3 25 Hz to 25 kHz 1 dB bandwidth ac coupled AM Distortion internal rates lt 1 5 lt 3 lt 5 0 to 30 AM 31 to 70 AM 71 to 90 AM FM MODULATION Maximum Peak Devia tion Afpk 3 Rates 260 Hz 99 kHz 0 1 to 123 5 MHz fc 25 kHz 123 5 to 247 MHz fc 50 kHz 247 to 494 MHz fc 99 kHz 494 to 990 MHz fc Rates 60 Hz 1600 x Rate 0 1 to 123 5 MHz fc 400 x Rate 123 5 to 247 MHz fc 800 x Rate 247 to 494 MHz fe 1600 x Rate 494 to 990 MHz fc FM not specified for fe Afpk lt 100 kHz Resolution 0 1 kHz Deviations lt 10 kHz 1 kHz Deviations 210 kHz Incidental AM lt 0 1 lt 20 kHz peak deviation and internal rates and carrier frequency 2500 kHz Indicator Accuracy3 5 of reading At internal rates
82. nd adapters It provides assurance that most of the front panel controlled functions are being executed by the Signal Generator EQUIPMENT PROCEDURE SPECTRUM ANALYZER FREQUENCY COUNTER RF INAY Figure 3 8 Test Setup for Basic Functional Checks Frequency Counter HP 5328A Option 031 Spectrum Analyzer HP 8558B 182T Preliminary Checks 1 Ensure that the power cableis plugged into a suitable source of Mains power refer to paragraph 2 4 2 Momentarily press and release the left hand side of the RESET STBY ON switch to initialize the Signal Generator then set the switch back to ON An internal memory check will be initiated to test for a failure in ROM read only memory and in RAM read write memory All front panel indicators will light for approximately 1 5 seconds to provide a quick visual inspection of each front panel annunciator and display segment If a memory failure is detected all front panel annunciators and display segments will remain lit until any front panel key is pressed If the memory check was success ful the front panel indicators will display a carrier frequency of 100 0000 MHz an output amplitude of 127 0 dBm and no modulation Only the dBm annunciator will be lit all of the others be off Connect the RF OUTPUT of the Signal Generator to the input of the frequency counter and the 10 MHz reference output from the frequency counter to the TIME BASE IN
83. ng Principles 8 21 Operational Amplifiers 0 8 21 Comparators its 8 22 vi Contents Model 8656A LIST OF ILLUSTRATIONS Figure Page Figure Page 1 1 HP Model 8656A Signal Generator with 5 14 Level and ALC Loop Detector Option 001 and Accessories Supplied 1 0 Adjustment Setup aman 5 18 5 15 Heterodyne Band Accuracy and Flatness 2 1 Line Voltage and Fuse Selection 2 2 Adjustment Setup 2 5 90 2 2 Power Cable and Mains Plug Part Numbers 2 3 5 16 AM and ALC Loop AM Adjustments 2 3 Time Base Jumper Location 2 5 Sean Ledere AA A 5 22 2 4 HP IB Address Switch Location and 5 17 FM Deviation Adjustment Setup 5 24 Settings u s cena n nanan NN KN 2 5 5 18 FM Frequency Response Setup 5 25 2 5 Hewlett Packard Interface Bus Connections 2 6 5 19 Attenuator Adjustment Setup 5 26 3 1 Simplified Front Panel Features 3 2 5 20 Attenuator Adjustment Locations 5 28 3 2 Display and Remote Features 3 5 5 21 10 MHz Reference Oscillator 3 3 Carrier Features oneone asawa 3 7 Frequency Adjustment Setup 5 29 3 4 Modulation Features 0 0 c cee eee ee 3 8 3 5 Data and Units Entry Features 3 9 6 1 Cabinet Parts Identification 6 35 3 6 Miscellaneous Features sseceeeeeee 3 10 6 2 Front Panel Parts Identification
84. ng instructions are for use by qualified per sonnel only To avoid dangerous electric shock do not perform any servicing unless qualified to do so BEFORE SWITCHING ON THE INSTRUMENT the protective earth terminal of the instrument must be connected to the protective conductor of the mains power cord The mains plug shail only be inserted in a socket outlet provided with a pro tective earth contact The protective action must not be negated by the use of an extension cord power cable without a protective conductor grounding Grounding one conductor of a two conductor outlet is not sufficient protection If this instrument is to be energized via an auto transformer for voltage reduction make sure the common terminal is connected to the earth termi nal of the power source Any interruption of the protective grounding conductor inside or outside the instrument or dis connecting the protective earth terminal is likely to make this instrument dangerous Intentional inter ruption is prohibited Whenever it is likely that the protection has been impaired the instrument must be made inoperative and be secured against any unintended operation Make sure that only fuses with the required rated current and of the specified type normal blow time delay etc are used for replacement The use of repaired fuses and the short circuiting of fuse holders must be avoided ii Model 8656A Adjustments described in t
85. ntenance 5 2 2 Vde Reference Adjustment Setup 5 4 and Servicing 25 ones Shae peda e ee sa eae 8 2 5 3 Audio Oscillator Level Adjustment Setup 5 5 8 2 Rear Panel and Fan Shroud Removal 8 7 5 4 AM Offset Adjustment Setup 5 6 8 3 Front Panel Pushbutton Switch Assembly 8 8 5 5 715 MHz Sideband Adjustment Setup 5 7 8 4 Pushbutton Switch Support Anvil 8 9 5 6 Notch Filters Adjustment Setup 5 8 8 5 Heat Staking Tipos bias tag iawn eens 8 9 5 7 High Frequency Loop Offset Adjustment 8 6 Typical Assembly for Heat Staking Setup AA do ap ND EEE 5 11 o A A EE ONENE 8 9 5 8 Tune Voltage Waveform ooooomomo o 5 12 8 7 Basic Logic Symbols and Qualifiers 8 12 5 9 50 MHz Reference Oscillator Frequency 8 8 Indicator Symbols Laudal dad ad wees wees 8 13 Adjustment Setup na AG ANG 5 13 8 9 Contiguous Blocks cs wa eee 8 14 5 10 50 MHz Reference Oscillator Level 8 10 AND Dependency Notation 8 14 Adjustment Setup oscar sad caawess 5 14 8 11 Address Dependency Notation Coder 5 11 60 to 110 MHz Oscillator Flatness Example Using Alpha Characters Adjustment Setup oooooommsocrcaconos 5 15 Letters AA AA AA 8 15 5 12 690 to 740 MHz IF Compensation 8 12 OR and Free Dependency Notation 8 15 Adjustment Setup X pusa ka hn TGA 5 16 8 13 Common Control Block 4 4 Kwak aa 8 15 5 13 400 MHz Bandpass Filter 8 14 Quad D Type Latch
86. nts on a device driven by the Signal Generator Switching times for frequency modulation and amplitude have several characteristics in com Table 3 8 HP 1B Program Codes Alphabetical Order ER Parameter Comments Code Amplitude Modulation Amplitude carrier dB dBf dBm Step Down 1 EMF Frequency Modulation Frequency carrier Hz Increment Set Percent Recall Reverse Power Protec tion Reset Standby On Sequence Store External Modulation Source Internal 400 Hz Modu lation Source i tion Source Modulation Source Off Step Up 1 uV Volts Numerals 0 9 Minus Sign Decimal Point Percent Internal 1 kHz Modula Function Entry Function Entry Units Entry Units Entry Units Entry Function Feature Units Entry Function Entry Function Entry Units Entry Function Qualifier Units Entry Units Entry Units Entry Units Entry Feature Feature Feature Feature Feature Feature Source Qualifier Source Qualifier Source Qualifier Source Qualifier Function Feature Units Entry Units Entry Data Entries Data Entry Data Entry Units Entry Program codes can be either upper or lower case 2 Bither PC or can be used 3 The source of reverse power must be removed 4 The RESET STBY ON switch must be set to the ON position Model 86564 Switching Characteristics Cont d mon In each case a finite am
87. nversion aaa 3 34 Amp1ltude UpZ DOWN vasse Ea 3 36 Display vask tied iad aes be ee ai 3 37 Display Sequence ces naa ese cas 3 38 PINE ON leader Gere 3 39 Frequency Coarse and Fine Tune 3 41 Frequency Un Down aka nk NGANGA NANG 3 43 HP IB Address Display saa 3 44 increment Value Change lt 0 aaa pans kme 3 46 Increment Value Display EET 3 48 Modulation AM las heel ah de 3 49 Modulation AM Up Down 0 0 ea ee 3 50 Modulation External Source ooocmomooo 3 51 Modulation BM aa RA 3 52 Modulation FM Up DowWN oomooomocrcoo 3 54 Modulation Mixed io oomorsoossororaronos 3 55 Modulation ODER cies soe aaa 3 59 A Paa ha a HG 3 61 SEQUE is ci cts TAN ina aaa 3 62 SON A GA LA bahag sn DAANG 3 63 Section IV PERFORMANCE TESTS a ios cobb acne NAL GP he ewe ANA NE DOT DA 4 1 Equipment Required sawaan 4 1 Performance Test Record aa 4 1 Calibration ONG id when DAGANG pha KE sn Ka KANA 4 1 Abbreviated Performance Testing 4 1 Test Pee SED 4 1 Spectral Purity Test pak aa Na NANANA 4 3 High Level Accuracy and Flatness Tests 4 8 Low Level Accuracy Tests oooooooooommo 4 11 Modulation Tests 000 cccccerececersceese 4 13 Output Leakage Tests oooocormmomomoooo 4 21 Section V ADJUSTMENTS Introduction Grossister AAA NA WANG 5 1 Safety Considerations ooooooooo
88. ocal operation Local Lockout The Signal Generator will return to local operation REN RLI Lockout and local lockout will be cleared when the REN bus Set Local control line goes false Pass Control The Signal Generator has no control capability CO Take Control Require The Signal Generator does not have the capability to Service request service ES The Signal Generator does not have the capability to Byte respond to a serial poll a Commands control lines and interface functions are defined in EEE Standard 488 and the identical ANS Standard MCI Knowledge of these might not be necessary if your controller s manual describes programming in terms of the twelve HP IB Messages shown in the left hand column above The Signal Generator does not have the capability to respond to a parallel poll The Signal Generator stops listening Complete HP B compatibility as defined in IEEE Standard 488 and the identical ANSI Standard MOL 1 is SHO AH1 TO L2 SRO RELI PPO DC1 DTO and CO ngi 3 24 Model 8656A Local Operation Cont d ables the LOCAL key and allows return to local only under program control NOTE Return to local can also be accom plished by setting the RESET STBY ON switch first to RESET then back to ON This technique however has some potential disadvantages e It defeats the purpose and advantage of local lockout that is the system controller will loos
89. oes not affect the actual output of the Signal Generator Does not change the contents of the internal sequence counter Does not affect the current increment settings Clears any previously selected function Feature is not accessible via HP IB All displays are restored to reflect the actual Signal Generator output when the Data key is released Related Display Sequence Instructions Recall Sequence Store 3 37 Operation Description Keystroke Sequence Example Keys and Indications Comments Related instructions 3 38 Model 8656A Display Sequence This instruction details how to display the contents of the internal sequence counter Press and release the DISPLAY key then press and hold the SEQ key Display the contents of the internal sequence counter am Display Sequence Counter Contents sus LOCAL keystrokes SEQ JP B This feature is not accessible via HP IB program codes DISLPAY SEQ The stored contents from the sequence counter will be displayed in the least significant digit of the AMPLITUDE Display as long as the SEQ key remains pressed Program Codes CEB Does not affect the actual output of the Signal Generator Does not change the contents of the internal sequence counter Clears any previously selected function Feature is not accessible via HP IB The AMPLITUDE Display is restored to reflect the actual Signal Generator output when the SEQ key is rele
90. on 3 31 Receiving the Pass Control Message The Signal Generator does not respond to the Pass Control message because it does not have a control capability 3 32 Sending the Require Service Message The Signal Generator does not have the capability to require service by setting the Service Request bus control line SRQ true 3 33 Sending the Status Byte Message The Signal Generator does not have the capability to respond to a Serial Poll Enable SPE bus com mand therefore it cannot send the Status Byte message 3 34 Sending the Status Bit Message The Signal Generator does not have the capability to respond to a Parallel Poll Enable PPE bus command therefore it cannot send the Status Bit message 3 35 Receiving the Abort Message The Abort message is the means by which the controller sets the Interface Clear bus control line IFC true When the Abort message is received the Signal Generator becomes unaddressed and stops listening 3 36 Switching Characteristics The Signal Generator s switching characteristics are an important consideration in applications involving a computer controller For most func tions the Signal Generator has the ability to accept new Data Messages before the hardware can settle to the required output If the timing requirements are not taken into account in the controller s pro 3 28 Model 8656A gram it will be impossible in many situations to make meaningful measureme
91. on using the internal modula tion source Operating Characteristics Depth 0 99 to 7 dBm 0 30 to 10 dBm Resolution 1 Rate internal 400 Hz and 1 kHz 3 Press and release an Internal Source key the AM Function key the desired Data keys and a valid Units key Select AM with a depth of 75 using the internal 400 Hz source omar SOUTCE men as FUNCTION mm aan JALA men suson LETS mm LOCAL keystrokes 5 S2AM75PC or Ganti tong Function Data program codes Program Codes Ree INT 400 Hz INT 1 kHz AM Selected AM depth will be displayed in the MODULATION Display and the source annunciators INT AM 400 Hz and will light Digits selected beyond the specified resolution for AM depth will be truncated Leading zeros will be blanked AM depth Data entries that would cause the peak envelope power of the instrument to exceed 17 dBm are rejected AM function will remain selected until a One of the three remaining functions is selected b One of the STORE RECALL DISPLAY keys is pressed c The instrument is reset or unplugged d The External Source key may be selected in place of the Internal Source key Modulation AM Up Down Modulation External Source Modulation Mixed Modulation Off 3 49 Operation _ Operation Description Keystroke Sequence Keys and Program Codes indications Comments Related instructions 3
92. onent Locations ooooooooom o o 8 65 8 56 Modulation and RF Amplitude Control Block Diagrams 7in0 cir 8 67 8 57 Modulation and RF Amplitude Control Schematic Diagram sis ved can IN KAG naa 8 67 8 58 Attenuator Component Locations Fon Veras sende 8 68 8 59 Attenuator Component Locations Bottom View hase nt AA 8 68 8 60 Attenuator Control Component Locations o oooooooo 8 69 8 61 Reverse Power Protection Component Locations ooooooooormommo 8 70 8 62 Attenuator Attenuator Control and Reverse Power Protection Block Diagrams 8 71 8 63 Attenuator Attenuator Control and Reverse Power Protection Schematic Diagram 8 71 8 64 LF Loop VCO Component Locations 8 72 8 65 LF Loop VCO Block Diagrams 8 73 8 66 LF Loop VCO Schematic Diagrams 8 73 8 67 LF Loop Data and Timing Control Component Locations 0 oooomoooomoc 8 81 8 68 LF Loop Data and Timing Control Block Diagrams an 8 83 8 69 LF Loop Data and Timing Control Schematic Diagrams cece eee 8 83 8 70 LF Loop Phase Lock Circuit Component TL OCALIONS a Coa Cae aa best 8 86 8 71 LF Loop Phase Lock Circuit Bloek Dass 8 87 8 72 LF Loop Phase Lock Circuit schematic Diagram 2 ccceedsasecvevewvres 8 87 8 73 LE Loop FM Calibrator Component Locations aa 8 91 8 74 LF Loop FM Calibrator Block Diagramme isi ASEAN Aga NN ere 8 93 8 75 LF Loop
93. ontents will be displayed but the actual output of the Signal Generator will not be affected The SEQ key is used to sequence the Signal Generator through each of its ten internal storage registers As the stored contents are sequentially recalled the output will be changed so that it agrees with the recalled parameter values When the DISPLAY key is used in conjunction with the SEQ key the stored contents of the internal sequence counter will be displayed in the least significant digit of the AMPLITUDE Display INCR SET Key A single key used in conjunction with any one of the four main function keys to store an increment value for that function The initialized value of each stored increment is listed as follows Carrier Frequency 10 0000 MHz Output Amplitude 10 0 dB AM Depth 1 FM Peak Deviation Frequency 1 0 kHz The minimum allowable increment value for each of the four main functions is listed as follows Carrier Frequency 0 1 kHz Output Amplitude 0 1 dB AM Depth 1 FM Peak Deviation Frequency 0 1 kHz e Figure 3 6 Miscellaneous Features 1 of 2 3 10 Model 8656A Operation INCR SET Key Cont d The maximum allowable increment value for each of the four main functions is listed as follows Carrier Frequency lt 989 99 MHz Output Amplitude lt 144 0 dB AM Depth lt 99 FM Peak Deviation Frequency lt 99 kHz The stored value of the increment will be displayed in the display associated with the sele
94. otection against fire haz ard replace the line fuse with only a 250V slo blo fuse of the same rating Do not use repaired fuses or short circuited fuseholders The only maintenance that the operator should normally perform is the replacement of the prim ary power fuse located within the Line Power Module A15 For instructions on how to change the fuse see Figure 2 1 steps 1 and 3 3 4 Fuses may be ordered under HP Part Numbers 2110 0305 1 25A 250V slo blo for 100 120 Vac operation and 2110 0016 0 6A 250V slo blo for 220 240 Vac operation 3 13 DETAILED PANEL FEATURES The Signal Generator is designed to be simple and easy to operate through the front panel The front panel primarily consists of 48 pushbutton keys three digital displays and 19 LED annunciators Each key has a single purpose and only one key should ever be pressed at any given time In most cases keys are pressed then released with the action occurring as the key is pressed In some cases a key must be pressed and held for the action to occur The four main functions of the Signal Generator are selected by the four dark gray colored keys labeled FREQUENCY AMPTD AM and FM The 27 medium gray colored keys are used to control the modulation source enter nu meric data and select the unit s which terminates the data entry The 15 light gray colored keys are used to set an increment value for each of the four main functions change main funct
95. ount of time passes from the command manual or computer gener ated until the required output occurs Software execution time is required for the microprocessor and related digital circuits to process the data This begins with a valid final terminator keys troke or data entry and ends with the execution in the hardware The software time may vary con siderably depending on the function Examples are internal instructions to more than one hard ware location may be serial parallel or both and differing amounts of control data and calculations Hardware execution time will also vary consider ably This depends on the number of circuits affected the length of time each takes to change and whether the changes occur one at a time or concurrently Frequency Switching The Signal Generator will typically be within 100 Hz of the final frequency within 2 seconds after receiving the valid units data terminator Figure 3 11 shows the sequence of events and the typical error frequency relative to time Area I shows the software execution time Areas II through IV make up the hardware execu tion time At times certain events in the frequency switching cycle may be bypassed For example small fre quency changes will often eliminate event II the fast slew rate mode or event IV the FM calibration mode However the frequency change that allows these events to be bypassed depends on an in volved algorithm that is a function of frequ
96. peration occurs Operation The front panel RMT and ADRS annunciators will both light once the Signal Generator has received the Remote message and is addressed to listen 3 28 Receiving the Local Message The Local message is the means by which the controller sends the Go to Local GTL bus com mand If addressed to listen the Signal Generator will return to local operation full front panel con trol when it receives the Local message If the instrument is in local lockout when the Local mes sage is received full front panel control will be returned but local lockout will remain in effect Unless the Signal Generator receives the Clear Lockout Set Local message it will return to local lockout the next time it receives a Remote mes sage All instrument settings remain unchanged when the transition from remote to local opera tion occurs The front panel RMT annunciator will be turned off when the Signal Generator switches to local operation However the front panel ADRS an nunciator will remain litifthe Signal Generator is still being addressed to listen whether in remote or local operation The front panel LOCAL key can also be used to return the Signal Generator to local operation However pressing the LOCAL key when the instrument is not in local lockout might interrupt a Data message being sent to the Signal Genera tor This would leave the Signal Generator in a state unknown to the controller This situation i
97. performing the basic functional checks as outlined in paragraph 3 15 o The bus controller properly executes HP IB operations e The bus controller s HP IB interface properly transfers the controller s instructions The select code of the bus controller s interface is set to 7 The HP IB address of the Signal Generator is set to 07 the factory set address e The select code address combination that is 707 is not necessary for these checks to be valid however the program lines presented in the following procedures would have to be modified for any other combination Ifthe Signal Generator appears to fail any of the remote functional checks the validity of the preceding assumptions should be confirmed before attempting to service the instrument 3 17 Operation OPERATOR S CHECKS AA Ea 3 16 HP 1B Functional Checks Cont d INITIAL SETUP EQUIPMENT If all of these checks are performed successfully the Signal Generator s HP IB capabil ity can be considered to be operating properly These procedures do not check whether or not all of the Signal Generator s program codes are being properly interpreted and executed by the instrument however if the front panel operation is confirmed to be working properly and its HP IB capability operates correctly then there is a high probability that the Signal Generator will respond properly to all of its program codes The test setup is the same for all of the chec
98. pple ment for this manual is identified with the manual print date and part number both of which appear on the manual title page Complimentary copies of the supplement are available from Hewlett Packard Forinformation concerning a serial number prefix that is not listed on the title page or in the MAN UAL CHANGES supplement contact your near est Hewlett Packard office 1 5 DESCRIPTION The Hewlett Packard Model 8656A is a synthe sized signal generator with a carrier frequency range of 100 kHz to 990 MHz Its output amplitude is leveled and calibrated from 13 to 127 dBm AM and or FM functions can be individually selected The carrier frequency output amplitude and modulation functions can be remotely pro grammed via the Hewlett Packard Interface Bus The unique modular design and incorporated ser vice features permit rapid and easy calibration and service 1 2 Model 8656A 1 6 Carrier Frequency The Signal Generator covers a carrier frequency range of 100 kHz to 990 MHz 10 kHz to 990 MHz with underrange which can be extended to 1 8 GHz with an external doubler Frequency resolu tion is 100 Hz or 250 Hz depending on the carrier frequency selected An 8 digit LED display of the carrier frequency in MHz is provided Pushbutton keys permit coarse tuning fine tuning and incre menting of the carrier frequency Frequency accuracy and stability are dependent on the reference source being used either the internal
99. preselected functions will remain unchanged when the local to remote transition occurs 3 20 Local Operation Local Capability In local operation the Signal Generator s front panel is fully operational and the instrument will respond to the Remote mes sage Whether addressed or not the Signal Gener ator will also respond to the Clear Local Lockout Clear Lockout Set Local and Abort messages It will not however respond to the Data message unless it has been previously addressed Remote to Local Change The Signal Generator returns to local operation upon receipt of the Local message GTL or Clear Lockout Set Local mes sage The Clear Lockout Set Local message sets the Remote Enable bus control line REN false The instrument can always be set to local opera tion by pressing the front panel LOCAL key pro vided that local lockout is not in effect The output signal will remain unchanged and all preselected functions will remain unchanged when ane remote to local transition occurs Local Lockout When a data transmission is inter rupted which can happen by returning the Signal Generator to local operation with the LOCAL key the data could be lost This would leave the Signal Generator in an unknown state To prevent this a local lockout is recommended Local lockout dis ables the LOCAL key and allows return to local 3 23 Operation Model 8656A Table 3 4 HP IB Message Reference Table
100. put amplitude down to 80 dBm and observe the level dis played on the spectrum analyzer The level should decrease in relatively uniform 5 dB steps FM Check 18 Set the output amplitude of the Signal Generator to 0 0 dBm Leave the carrier frequency set to 600 MHz Select FM with a peak deviation frequency of 99 kHz using the internal 1 kHz source Set the FM peak deviation frequency increment value to I kHz 19 Set the spectrum analyzer for a 50 kHz frequency span division a resolution band width of 3 kHz and a reference level of 0 dBm The waveform displayed should be similar to that shown in Figure 3 9 20 Slowly decrease the FM peak deviation frequency to zero The deviation displayed on the spectrum analyzer should decrease in relatively uniform steps 21 Press FM then OFF to turn off the FM function TU a TG ae MUA A E il ES ENE mau am CL Ma a HL re E L T Figure 3 9 FM Functional Check Waveform 3 16 Model 8656A Operation OPERATOR S CHECKS 3 15 Basic Functional Checks Cont d AM Check 22 Leave the carrier frequency set to 600 MHz and the output amplitude set to 0 0 dBm Select AM with a depth of 50 using the internal 400 Hz source 23 Set the spectrum analyzer to the linear amplitude mode Set a frequency span divi sion of zero Increase the resolution bandwidth then fine tune for the maximum level of the demodulated signal The displayed demodulated
101. r UG 210 U HP 11500B PA T Type N m TA Adjustments P Performance Tests T Troubleshooting 2The residual AM specification of both the HP 8901A Modulation Analyzer and HP 11715A AM FM Test Source are stated in a 50 Hz to 3 kHz bandwidth In order to assure the validity of the residual AM measurement in the bandwidths stated for the HP 8656A Signal Generator namely 50 Hz to 15 kHz the combined performance of both the HP 8901A and HP 11715A must be verified to be better than 0 022 rms for the 50 Hz to 15 kHz bandwidth See paragraph 4 7 step 4 for the verification procedure The incidental AM specification of the Signal Generator is not equivalent to the published specification of the Model 8901A Modulation Analyzer In order to assure the validity of the incidental AM measurement the incidental AM of the modulation analyzer must be verified to be less than 0 02 for the 300 Hz to 3 kHz bandwidth and 20 kHz peak deviation at internal rates Refer to paragraph 4 10 step 18 for the verification procedures Table 1 4 Alternate Test Equipment Recommended Model Suggested Alternative Advantages of Alternative Controller HP IB HP 9825A 98213A 98034A Digital Voltmeter HP 3465A HP 3455A DVM HP 339A HP 8903A HP 1B Compatible Frequency Counter HP 5328A Option 031 HP 5328A Options 001 HP IB Compatible and 031 HP 436A HP 436A Option 022 HP IB Compatible Oscilloscope HP 1222A HP
102. rator s Maintenance The only maintenance that the operator should normally perform is the replacement of the primary power fuse All other maintenance should be referred to qualified service personnel 3 7 GENERAL OPERATING INSTRUCTIONS WARNINGS Before the Signal Generator is switched on all protective earth terminals extension cords autotransformers and devices con nected 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 For continued protection against fire hazard replace the line fuse with only a 250V slo blo fuse of the same rating Do not use repaired fuses or short circuited fuseholders CAUTIONS Before the Signal Generator is switched on it must be set to the same line voltage as the power source or damage to the instru ment may result The Signal Generator is protected against reverse power applica tions up to 50 watts however for greatest protection of expensive internal components be careful not to apply any reverse power to the RF OUTPUT connector 3 8 Power On Procedure The Signal Generator has a standby state and an on state Whenever the power cable is plugged in the internal power supply is activated If the instrument is equipped with the high stability reference Option 001 the oven will be energized to keep the reference oscillator stable If the Signal
103. reviated Performance Tests 4 2 1 2 Supplemental Characteristics 1 7 4 2 Performance Test Record 4 23 1 3 Recommended Test Equipment 1 8 L Rene Hd do paaa Ki 5 1 Factory Selected Components 5 1 2 1 Line Fuse Ratings and Part Numbers 2 2 5 2 Post Repair Adjustments a 5 2 2 2 Allowable HP IB Address Codes 2 4 5 3 Attenuator Pad Adjustment Information 5 27 3 1 Initialized Conditions 43 6530 6 beatae wees ets 31 3 2 Operating Characteristics ol 6 1 Reference Designations ooooooomm 6 3 3 3 Index of Detailed Operating Instructions 33 6 2 Abbreviahonsius sa oak KENA LAS BONGGA se wees 6 3 3 4 HP IB Message Reference Table 3 24 6 3 Replaceable Parts aaa sw wawa an a 6 5 3 5 Valid Decimal Values vs Equivalent 6 4 Code List of Manufacturers oooocoommo o 6 34 ASCII Characters tada ie 3 25 a Input Data Restrictions vssedrsyesasrsskaree 3 26 7 1 Manual Changes by Serial Number 7 1 3 7 Response to Clear Message 3 27 7 2 Summary of Changes by Component 7 9 3 8 HP IB Program Codes TE a ga ny te Bee N Alphabetical Orden ira tienes er 3 28 3 9 HP IB Program Codes 8 1 Assembly Access Information 8 6 Functional Order decias es bi 3 29 8 2 Etched Circuit Soldering Equipment
104. rnal carrier frequency increment register The value of the carrier frequency increment initially stored is 10 0000 MHz Its minimum value is 100 Hz and its maximum value is lt 989 99 MHz The carrier frequency will be changed once for each keystroke or repeatedly if either key remains pressed The COARSE TUNE and FINE TUNE keys are used in conjunction with the frequency step up and step down keys to tune the carrier frequency They are used to increase COARSE TUNE or decrease FINE TUNE the carrier frequency tuning value by a factor of 10 The affect of these keys is disabled and the original carrier frequency increment value is enabled when the INCR SET key is pressed If a changein carrier frequency causes the FM peak deviation frequency allowed for that frequency band to be exceeded the MODULATION Display will flash until a carrier frequency within the correct band is selected or the FM FM step up or FM step down key is pressed In this later case the maximum FM peak deviation frequency permitted for the currently selected carrier frequency will automatically be selected The AMPTD key is one of the four main function keys Itis used in conjunction with all of the Data and UNITS entry keys to enter output amplitude parameters In addition it is used in conjunction with the INCR SET key to enter output amplitude increment values Further it is used to reset the internal reverse power protection feature once the source of reverse power
105. rough an external switch closure connected at the rear panel SEQ connector J5 Related Display instructions Display Sequence Recall Store 3 62 Model 8656A Description Keystroke Sequence Example Keys and Program Codes indications Comments Related instructions Operation Store This instruction details how to store complete front panel setups exclusive of incre ment settings for either selectable or sequential recall or display at a later time Press and release the STORE key then a Data key a single digit register number 0 9 Store the current front panel settings in register 2 mm Store Settings in Register 2 sum LOCAL keystrokes 2 ST2 Store Settings in Register 2 No visible front panel change Ten internal registers are available 0 9 Each is capable of storing complete front panel setups exclusive of increment settings Clears any previously selected function Initialized conditions of the Signal Generator are stored in each of the ten internal storage registers when the instrument is powered up or reset Display Recall Sequence 3 63 3 64
106. rsvebaskenes 8 3 Parts and Cable Locations 0 0000 8 3 Test Points and Adjustment Locations 8 3 Service Aids on Printed Circuit Boards 8 3 Other Service Documents 000s romo 8 3 Troubleshooting GS saaan na hnd Hea Tia ka Nag ee 8 3 entra dd AE 8 3 Operator Error AAP 8 3 Instrument Out of Specification 8 4 Catastrophic Failures oooomomo os 8 4 DELAS bis 8 4 Overall Troubleshooting Service Sheet BD1 8 4 Functional Section Troubleshooting Service Sheets BD2 BD4 sd ts 8 4 Cireuit Troubleshooting Service Sheets 1 22 o aaa 8 4 Signature Analysis 2 sasa 8 4 Additional Information aaa 8 5 FREDO da bae 8 5 Disassembly Procedures ccccuccvceceee 8 5 Front Panel Removal o ooooooomo o 8 5 Al Keyboard and A2 Display Assembly Removal ven cited E lea ead Siew de 8 5 Cover Removal Top and Bottom Levels Land ACCOR ba aaa sd 8 5 A3 Assembly Service Position 8 6 PA havin vate eeu cuter eae PY NT 8 6 A10 A11 Assemblies Service Position 8 7 Level 3 ACCESS daa 8 7 Rear Panel Removal omic 8 7 Contents Page Fan Shroud Removal o o ooooo 8 8 Replacement of Key Cap and Pushbutton Switches AA RA 8 8 Key Cap Replacement asaan 8 8 Switch Replacement 0 cc anan 8 8 Factory Selected Components 8 10 Manual Backdating F
107. rtion Analyzer Distortion Range lt 0 1 HP 339A or HP 8903A P T Range 25 Hz to 25 kHz see Table 1 4 Range 10 MHz Resolution 1 Hz HP 5328A Option 031 or HP 5328A Options 001 and 031 see Table 1 4 Frequency Counter Range 990 MHz Resolution 10 Hz Frequency Counter HP 5328A Option 031 HP 008640 60501 To ensure measurement accuracy no substitution is possible Fabrication depends upon machining and assembling to close tolerances Loop Antenna 2 5 cm 1 in Frequency Range 150 kHz to 990 MHz 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 0 396 for 50 depth lt 0 6 for 90 depth Incidental PM lt 0 05 radians for 50 depth at 1 kHz rate 50 Hz to 3 kHz bandwidth Residual AM Modulation Analyzer HP 8901A P A 1 8 Model 8656A General Information Table 1 3 Recommended Test Equipment 2 of 3 Critical Specifications Recommended Model Use HP 1222A or A T HP 1801A 1820C 181A see Table 1 4 Frequency Modulation Rates 25 Hz to 25 kHz Deviation to 99 kHz Accuracy 2 at 1 kHz Demodulated Output Distortion lt 0 3 Incidental AM3 Residual FM lt 8 Hz rms at 1300 decreasing linearly with frequency to lt 1 Hz rms for 100 MHz and below 50 Hz to 3 kHz bandwidth Modulation Analyzer Cont d V
108. s REMOTE OPERATION HP IB IEEE 488 Capability Interface Hewlett Packard Interface Bus HP IB HP IB is Hewlett Packard s imple mentation of IEEE Standard 488 and the identical ANSI Standard MC1 1 The Signal Generator s compatibility with HP IB is defined by the follow ing list of interface functions SHO AH1 To L2 SRO RL1 PPO DC1 DTO and CO All functions controlled from the front panel with the exception of DIS PLAY DISPLAY in conjunction with SEQ Backspace COARSE TUNE FINE TUNE and display HP IB ADRS are programmable with the same accuracy and resolution as in local operation Functions Controlled 1 6 Model 8656A General Information Table 1 2 Supplemental Characteristics Supplemental characteristics are intended to provide information useful in applying the instrument by giving typical but non warranted performance parameters FREQUENCY Accuracy and Stability same as internal time base Time Base Characteristics a Standard Option 001 Characteristic Time Base 1 x 10 8 day 10 ppm 7X 10 9 0 55 0 055 C 2X 10 9 5 to 10 Frequency 50 MHz 10 MHz Time Base Available at a level of 50 15 Vrms Reference Signal into 50 ohms output of 10 5 or Rear Panel 1 MHz is selectable via internal jumper If the Option 001 or another external reference is used only that reference frequency is available as an output External Reference Accepts any 10 5 or 1 MH
109. s undesirable and can be avoided by sending the Local Lockout message to disable the LOCAL key 3 29 Receiving the Local Lockout Message The Local Lockout message is the means by which the controller sends the Local Lockout LLO bus command If the Signal Generator is in remote operation it will respond to the Local Lockout message by disabling the front panel LOCAL key Local lockout prevents the loss of data or system control due to someone accidentally pressing any of the front panel keys If the Signal Generator is in local operation when it is enabled to remote operation that is REN is set true and it receives the Local Lockout message it will switch to remote with local lockout operation the first time it is addressed to listen Once in local lockout the Signal Generator can only be returned to local operation by the controller or by unplugging or resetting the instrument 3 27 Operation 3 30 Receiving the Clear Lockout Set Local Message The Clear Lockout Set Local message is the means by which the controller sets the Remote Enable bus control line REN false The Signal Generator will return to local operation full front panel control when it receives the Clear Lock out Set Local message All instrument settings remain unchanged when the transition from re mote with lockout to local operation occurs The front panel RMT annunciator will be turned off when the Signal Generator switches to local operati
110. s Selection Feature is not accessible via HP IB The MODULATION Display is restored to reflect the actual Signal Generator output when the HP IB ADRS key is released Model 8656A Model 8656A Operation i ver Serre agarang an baa Comments Allowable HP 18 Address Codes Coni d EQUIVALENT EQUIVALENT ADDRESS SWITCH ASCII DECIMAL CHARACTER VALUE Palm ee 0 EE PA bd hd pi pod ht OOOO OOO OR O ODO ID OA WNH Dn Hee OOOCORP HER OOD OM HM m HE OOO Om mi pi HM OOOO MOOR FOC ODO OOR FOO Rr MODO RH OO mem OO CHOH OH OM OH OP DH OR OH OR OH OM OH OR OR 0 0 0 0 0 0 J i I I 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 i Be Indicates factory set address Related None Instructions 3 45 Operation Description Keystroke Sequence Keys and Program Codes Indications Comments 3 46 Model 8656A This instruction details how to change the value of the stored increments which are controlled by the step up and step down keys associated with each of the four main functions Increment values for the carrier frequency output amplitude AM depth and FM peak deviation frequency can be stored The initialized value of each stored increment is listed as follows Carrier Frequency 10 0000 MHz Output Amplitude 10 0 dB AM Depth 1 FM Peak Deviation Frequency 1 0 kHz Press and release a Function key the INCR SET key the desired Data keys and a valid Units
111. s assumed that the Signal Generator is able to handshake recognize its own address and properly make remote localtransitions The Data message that is sent will cause the 7 least significant HP IB data lines to be placed in both their true and false states Before beginning this check set the RESET ST BY ON switch to RESET then back to ON to initialize the instrument 3 19 Operation OPERATOR S CHECKS 3 16 HP IB Functional Checks Cont d Description HP 9825A HP 9835A and HPL HP 9845A BASIC Send the first part of the rem 707 REMOTE 707 Remote message which enables the Signal Generator to remote wrt 707 Fr990mz OUTPUT 707 FR990MZ Address the Signal Generator to listen which completes the Remote message and send the Data message which tunes the Signal Generator to 990 MHz OPERATOR S Verify that the Signal Generator s RMT and ADRS annunciators both light and that the RESPONSE FREQUENCY Display shows a carrier frequency of 990 0000 MHz Local Lockout and Clear Lockout Set Local Messages NOTE This check determines whether or not the Signal Generator properly receives the Local Lockout message which disables all of the front panel keys In addition this check determines whether or not the Clear Lockout Set Local message is properly received and executed by the Signal Generator It is assumed that the Signal Generator is able to handshake recogniz
112. s normal position Insert a fuse of the correct value in the holder Close the cover door WARNING To avoid the possibility of hazardous electri cal shock do not 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 Figure 2 1 Line Voltage and Fuse Selection Table 2 1 Line Fuse Ratings and Part Numbers 1 25A 250V SLO BLO HP 2110 0305 0 6A 250V SLO BLO HP 2110 0016 2 6 Power Cables BEFORE CONNECTING THIS INSTRU MENT the protective earth terminal of the instrument must be connected to the protective conductor of the Mains power cord The Mains plug shall only be inserted in a socket outlet provided with a protective earth contact The pro tective action must not be negated by the use of an extension cord power cable without a protective conductor grounding Grounding one conductor 2 2 Model 8656A of a two conductor outlet is not suffi cient protection This instrument is equipped with a three wire power cable When connected to an appropriate ac power receptacle this cable grounds the instru ment cabinet The type of power cable plug shipped with each instrument depends on the country of destination Refer to Figure 2 2 for the part num bers of the power cables and Mains plugs available 2 7 Time Base Selection One of three time base output signals 1 5 or 10
113. slide the cover in the direction of the arrow then lift the side cover away from the frame Finally lift the bottom cover away from the frame b Locate the HP IB address switches S3 and S4 on the Microprocessor Memory HP IB Assembly All see Figure 2 4 c Use a pencil to set the switches to the desired HP IB address in binary see Figure 2 4 The five switches are labeled Al through A5 where Al is the least significant address bit and A5is the most 2 3 Installation Installation gt Table 2 2 Allowable HP IB Address Codes Equivalent Equivalent Address Switch ASCH Decimal Character Value LISTEN LISTEN os Ka O OO mn o m id n OD OD DD KH KH mme D ODO Gs N mm ON O Mm HD Ut a Co bl kot kot hw fk ok forf rt hub jab hek bab hb DD DD DD O TB 2 O o fa bs po a a ar DD O O O O O O FP ka ka pa a h l m DD a Km Or a DD RF RP OD mm FP OOo a o Drm DH Q me QD HD HD a Cr Om OD nm Oe Onu Q ndicates factory set address HP iB Address Selection Cont d significant address bit Pressing the right hand side of the switch as viewed from the front of the instrument sets the corresponding address bit bit 1 while pressing the left hand side clears the bit bit 0 Setting all of the address bits to 1 will result in an invalid HP IB address 31 deci mal In this case an HP IB address of 30 deci mal will be stored in memory once the instrument is powered up or reset 2 4
114. storing complete front panel setups exclusive of increment settings Clears any previously selected function Updates the contents of the internal sequence counter so that it agrees with the numerical location of the recalled register Does not affect the current increment settings Display Store Sequence 3 61 Operation Model 8656A Sequence Description This instruction details how to sequentially recall the stored contents from each ofthe internal storage registers Keystroke Press and release the SEQ key Sequence Example Sequentially recall the stored contents from each of the internal storage registers ans Recall Contents fram Next Sequential Storage Register em LOCAL keystrokes seq SQ program codes Recali Contents from Next Sequential Storage Register Keys and Program Codes Program Codes 4 N indications The stored contents from each internal storage register will be recalled and the output of the Signal Generator will be changed so that it agrees with the recalled parameter values Comments Ten internal registers are available 0 9 Each is capable of storing complete front panel setups exclusive of increment settings Does not clear any previously selected function Updates the contents of the internal sequence counter so that it agrees with the numerical location of the recalled register Does not affect the current increment settings Remote sequence operation is permitted th
115. strings Figure 3 10 provides some examples of Data messages Keyboard to Program Code Correlation Thereis a program code that corresponds to nearly every front panel key The exceptions are DISPLAY DISPLAY in conjunction with SEQ Backspace COARSE TUNE FINE TUNE and display HP IB ADRS In addition the program code HZ is available for carrier frequency entries RP is avail able to reset the reverse power protection circuitry after the source of reverse power has been re moved and RO and RI are available to program matically place the instrument in the STBY and ON states respectively Value Selectable Parameters Carrier parameters are set using a Function Data Units sequence of program codes while modulation parameters are set using a Source Function Data Units sequence of program codes Single value parameters such as INT 400 Hz INT 1 kHz and so forth are set with a single program code sequence Model 8656A Data The term Data in each program sequence refers to the numeric value and not to the entire Data message Data can be any number of arbi trary length in fixed point notation Digits that exceed the maximum data length for the particular function will be truncated This maximum limit includes any embedded decimal point In the case of the Amplitude function this maximum limit also includes the minus sign The minus sign is only applicable during Amplitude Data entries Table 3 6 summarizes these inp
116. stroke Sequence Keys and Program Codes Indications Comments Related instructions Operation Modulation External Source This instruction details how to apply an external modulation signal via the front panel MOD INPUT OUTPUT connector Operating Characteristics Rate for AM or FM 25 Hz to 25 kHz 1 dB bandwidth ac coupled Input Imperiance 600 ohms resistive Input Level 1 Vpk 0 707 Vrms Press and release the EXT key to enable the front panel MOD INPUT OUTPUT connector then set the signal level of the external modulation source to 1 Vpk 0 707 Vrms for calibrated internal control of the AM depth or FM peak deviation frequency Program Codes The HI EXT annunciator will light if the external modulation signal is greater than 1 02 Vpk 0 721 Vrms and the LO EXT annunciator will light if the signal is less than 0 98 Vpk 0 693 Vrms NOTE If greater accuracy is required use a calibrated voltmeter to measure the external modulation signal In addition to being able to accept an external modulation signal the MOD INPUT OUTPUT connector provides access to the internally generated 400 Hz or 1 kHz signal whenever either is selected and the external modulation source is not selected Its signal level is 1 Vpk 0 707 Vrms and it cannot be adjusted by the operator Modulation AM Modulation FM Modulation Mixed Modulation Off 3 51 Operation Model 8656A Modulation FM Description This instru
117. t Locations 8 103 Component Locations s 8 120 8 85 Microprocessor Interrupt Processing and 8 105 Frequency Displays Block Diagrams 8 121 Restart Block Diagrams 8 105 8 106 Frequency Displays Schematic Diagram 8121 8 86 Microprocessor Interrupt Processing and 8 107 Amplitude Modulation and Annunciator Restart Schematic Diagram 8 105 Displays Component Locations 8 123 8 87 Address Buffering and Decoding Serial I O 8 108 Amplitude Modulation and Annunciator and Control Component Locations 8 106 Displays Block Diagrams 8 125 8 88 Address Buffering and Decoding Serial 1 O 8 109 Amplitude Modulation and Annunciator and Control Block Diagrams 8 107 Displays Schematic Diagram 8 125 8 89 Address Buffering and Decoding Serial I O 8 110 Voltage Regulator and Control Schematic Diagram 8 107 Component Locations o ooo oooo 8 126 8 90 Memory Component Locations 8 110 8 111 Filter Bank Component Locations 8 126 8 91 Memory Block Diagrams 8 111 8 112 Power Supply A10 Assembly 8 92 Memory Schematic Diagram 8 111 Component Locations oooooooroo 8 127 8 93 HP IB Connector Component Locations 8 112 8 113 Power Supply Schematic Diagram 8 127 TABLES Table Page Table Page 1 1 Specifications A nA KAKO APANG ANG 1 4 4 1 Abb
118. tainer for damage If the shipping container or cushioning material is dam aged 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 Figure 1 1 Procedures for checking electrical performance are given in Sec tion IV If the contents are incomplete if there is mechanical damage or defect or if the instrument does not pass the electrical performance test not ify the nearest Hewlett Packard office If the ship ping 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 WARNING To avoid the possibility of hazardous electrical shock do not operate this in strument at line voltages greater than 126 5 Vac with line frequencies greater than 66 Hz Leakage currents at these settings may exceed 3 5 mA The Signal Generator requires a power source of 115 90 to 126 Vac or 230 198 to 252 Vac 48 to 66 Hz single phase Power consumption is 125 VA maximum WARNINGS This is a Safety Class I product fi e provided with a protective earth termi nal An uninterruptible safety earth ground must be provided from the Mains power source to the product input wiring terminals power cord or supplied pow
119. tallation available through Hewlett Packard offices If the instrument is being returned to Hewlett Packard for servicing attach a tag indicating the type of service required return address model number and full serial number Also mark the container FRAGILE to assure careful handling In any cor respondence refer to the instrument by model number and full serial number Other Packaging The following general instruc tions should be used for repackaging with com mercially available materials a Wrap the instrument in heavy paper or plas tic If shipping to a Hewlett Packard office or ser vice center attach a tag indicating the type of service required return address model number and full serial number 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 millimetre layer 3 to 4inches around all sides of the instrument to provide a firm cushion and to 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 2 7 2 8 Model 8656A 0 O OC aaaaaa 3 1 INTRODUCTION This section provides complete operating infor mation for the Signal Generator Included are both general and detailed operating instructions detailed descriptions of each front and rear panel
120. tant demodulated signal is less than 8 at 1 kHz deviation for a 10 Hz square wave modulating signal Simultaneous Modulation internal and external AM and FM Internal external AM FM FM AM AM AM and FM FM AM Incidental to FM lt 1 for 200 kHz lt f lt 500 kHz and lt 5 for 100 kHz lt fe lt 200 kHz 1 7 General Information Model 8656A Table 1 3 Recommended Test Equipment 1 of 3 Critical Specifications Recommended Model AM FM Test Source Range 10 to 400 MHz HP 11715A required for Residual AM modulation analyzer FM Flatness 1 de to 250 kHz verification Peak Deviation to 100 kHz Attenuation 20 dB HP 8491A Option 020 Frequency Range 10 MHz to 990 MHz SWR lt 1 2 Attenuator Fixed Attenuation 60 dB Frequency Range 100 kHz to 990 MHz Accuracy 2 dB 0 16 dB at Standards Calibra tion Lab Frequencies of 10 100 201 801 901 and 990 MHz SWR lt 1 3 Attenuator Fixed HP 8491A Option H56 Controller HP IB HP IB compatibility as defined by IEEE Standard HP 9825A 98034A A T 488 and the identical ANSI Standard MC1 1 98213A or HP 9835A SHO AH1 T4 TEO LO LEO SRO RLO PPO DCO 98332A 98034A DTO and C1 2 3 28 see Table 1 4 Digital Multimeter Accuracy 4 1 2 digit 0 02 of reading 1 digit HP 3465A or P A T Ranges 20 mV to 30 Vde and 2 Vac HP 3455A Sensitivity 100 uV see Table 1 4 Disto
121. tor does not have the capability to respond to the trigger message 3 26 Receiving the Clear Message The Signal Generator will respond to a Clear mes sage by setting each function parameter to the value listed in Table 3 7 The Signal Generator will respond equally to the Selected Device Clear SDC bus command when addressed to listen and to the Device Clear DCL bus command whether addres sed or not Table 3 7 Response to Clear Message Carrier Frequency 100 0000 MHz Output Amplitude 127 0 dBm AM Depth 0 FM Peak Deviation Frequency 0 0 kHz Carrier Frequency Increment 10 0000 MHz Output Amplitude Increment 10 0 dB AM Depth Increment 1 FM Peak Deviation Frequency 1 0 kHz Increment Coarse and Fine Tune Pointer 10 0000 MHz Sequence Counter 0 All 10 Internal Storage Registers Remain unchanged 3 27 Receiving the Remote Message The Remote message is comprised of two parts First the Remote Enable bus control line REN is held true then the device listen address is sent by the controller These two actions combine to place the Signal Generator into remote operation There fore the instrument is enabled to go into remote operation when the controller begins the Remote message but it does not actually make the transi tion until itis addressed to listen for the first time All instrument settings remain unchanged when the transition from local to remote o
122. ts ooooooomommmom 6 1 Parts List Backdating 7 oooooomommomm or 6 1 Parts List Updating Change Sheet 6 1 Illustrated Parts Breakdowns 6 1 Ordering Information o ooooomoomommoroo 6 1 Recommended Spares List o oo o eooo o 6 2 Section Vi MANUAL CHANGES a iia cased BA A 7 1 Manual Changes sura ratita 7 1 Manual Change Instructions 0 0 0 ee eens 7 3 Instrument Improvement Modifications 7 10 Improving Power Supply Reliability 7 10 Decreasing Spurious Signal Output 7 10 Improving Low Level Accuracy 7 10 Improving RF Frequency Response 7 11 Loss of Signal Generator Control by the Keyboard A IN ER 7 11 Section Vill SERVICE Introduci n da oak ca dah LNG KA ma tech etek ee ba 8 1 Model 8565A CONTENTS Cont d Page Service Sheets AA A id 8 1 Block Diagrams 242242 daa wih ARAWAN NAA k ne 8 1 Circuit Schematic Diagrams 8 1 Safety Considerations oooooomcosmommo s 8 1 Before Applying Power oooooomcccorommmo 8 1 Warnings and Cautions aaa 8 1 Recommended Test Equipment and KOSE A ade 8 2 Service Tools Aids and Information 8 2 Service A Wu OS PANA Kee 8 2 Pozidriv Screwdrivers oooooconcconmmmm o o o 8 2 Tuning Tools od aha paa Suan Gul DEE SA ite 8 2 Heat Staking DO as 8 2 Assembly Locations sarsessvmsnsre
123. tt Packard Interface Bus 1 3 Time Base Selection YAN AA AA AN aes sa Compatibility 8 Operator s Maintenance nananana 34 Selecting the HP IB Address 1 3 Detailed Panel Features cece eee eee 3 4 Accessories Supplied Jl 1 3 Operator s Checks BRENT WG rrr em ree ee 3 13 Recommended Test Equipment 13 Basic Functional Checks EEE 3 13 HP IB Functional Checks ooooommomomomo 3 17 Section II Remote Operation Hewlett INSTALLATION Packard Interface Bus sa sana amen NAL 3 23 EE ENE aha ngana 2 1 HP IB Compatibility ocultos 3 23 Initial Inspection sia NAGANA NANG WA 2 1 Remote Operation SEN Pe eee de 3 28 Preparation for Use ccscecceccccccuccecceee 2 1 Remote Capability rare KARGA GANG 3 23 Power Requirements 0 roca 24 Local to Remote Change anal gaga draw 3 23 Line Voltage and Fuse Selection 2 1 Local Op Gration o 0 sees eee eee ee eee e tees 3 23 Por AA 2 9 Local Capability rei edi 3 23 Time Bare Selection o Irra tis a ea 9 9 Remote to Local Change ooomoomomo o 3 23 HP IB Address Selection 2 3 Local Lockout o oooronsonornoccncconono coo 3 23 Interconnection A DAN 2 4 Addressing 2 1 1 1 6s sieeve settee eee nananana 3 25 Mating Conneelors ret bka 24 Data Messages oia KLANG AN deras are 3 25 Fase AA 2 4 Receiving the Data Message 3 25 Interface Connector aa 2 4 Data Message
124. uency would cause the FM peak deviation frequency allowed for that frequency band to be exceeded Entering a carrier frequency that would set the instrument in the correct band for the selected deviation frequency will clear the error condition or pressing one of the following keys will automatically adjust the FM peak deviation frequency to the maximum frequency possible for that frequency band Band Carrier Frequency MHz 1935 247 247 494 494 990 FM function will remain selected until a One of the three remaining functions is selected b One of the STORE RECALL DISPLAY keys is pressed c The instrument is reset or unplugged d The External Source key may be selected in place of the Internal Source key Modulation FM Up Down Modulation External Source Modulation Mixed Modulation Off Operation Description Keystroke Sequence Keys and Program Codes indications Comments Related instructions 3 54 Model 8656A Modulation FM Up Down This instruction details how to change the FM peak deviation frequency by the value stored in the internal FM peak deviation frequency increment register Press and release the step up or step down keys associated with the frequency modulation function Program Codes NOTE During remote operation repeated UP or DN codes can be sent over the bus once the FM function has been selected The FM peak deviation frequency shown in the MODULA
125. ument Included are instructions for setting carrier functions setting modulation func tions and changing parameter values This is a good starting point for the first time user Table 3 3 provides an index in functional order to the detailed operating instructions This index is in tended to direct the user to the more complete oper Operation ating instructions which are arranged alphabeti cally at the end of this section General Operating instructions Instructions relat ing to the Signal Generator s power on procedure power on sequence various keystroke sequences and time base selection are presented to acquaint the user with the general operation of the instrument Detailed Panel Features Front and rear panel fea tures are described in detail in Figures 3 2 through 3 7 Detailed Operating Instructions The detailed oper ating instructions present the most comprehen sive information about all of the Signal Genera tor s functions These instructions are arranged alphabetically by subject and are included at the end of this section for easy reference They are indexed in functional order in Table 3 3 3 4 Remote Operation 4 b kaka sts The Signal Generator is capable of remote opera tion via the Hewlett Packard Interface Bus Know ledge of local operation is essential for HP IB pro gramming since most of the data messages con tain the same keystroke like sequences HP IB information is present
126. ut amplitude increment register This stored value is used in conjunction with the step up and step down keys associated with the amplitude function to change the output amplitude Further the least significant digit of the AMPLITUDE Display is used te display the stored contents of the internal sequence counter Also whenever a reverse power condition is detected all segments and all seven LED annunciators associated with the AMPLITUDE Display will flash until the source of reverse power is removed and the AMPTD key is pressed Seven LED annunciators are used to display output amplitude unit information Fourteen unit combinations are possible which will cause one or more LED s to light The valid output amplitude units are listed as follows dBm dB uV V EMF mV dBf dB EMF V mV EMF V dB V dB EMF mV uV dB mV dB EMF V EMF V MODULATION Display The MODULATION Display provides a 2 digit display of AM depth from 0 to 99 with a resolution of 1 or FM peak deviation frequency from 0 to 99 kHz with a resolution of 0 1 kHz for deviations lt 10 kHz or 1 kHz for deviations 210 kHz AM depth is always displayed in percent Figure 3 2 Display and Remote Features 1 of 2 MODULATION Display Cont d and FM peak deviation frequency is always displayed in kHz Digits selected beyond the specified resolution will be truncated and leading zeros will be blanked If one modulation parameter is being displayed when the other modul
127. ut amplitude function are used to change the output amplitude by the value stored in the internal output amplitude increment register Places the instrument in the Amplitude Data entry mode and clears any previously selected function Continues to change the output amplitude by the value stored in the internal output amplitude increment register if either key remains pressed Initialized value and limits of the output amplitude increment are as follows Inittalized Minimum Maximum Value Value Value 10 0 dB 0 1 dB lt 144 0 dB 0 001 nV lt 1 57V 0 001 EMF uV lt 3 15 EMF V Related Increment Value Change Instructions Increment Value Display 3 36 Model 8656A Operation Display Description This instruction details how to selectively display the stored contents of an internal storage register Keystroke Press and release the DISPLAY key then press and hold the Data key a single digit Sequence register number 0 9 Example Display the stored contents from register 2 LOCAL um Display Contents of Register 2 keystrokes 2 gt This feature is not accessible via HP IB program codes Keys and Program Codes Keys CEE NGA DISPLAY indications The stored contents from the selected register will be displayed as long as the Data key remains pressed Comments Ten internal registers are available 0 9 Each is capable of storing complete front panel setups exclusive of increment settings D
128. ut data restrictions Table 3 6 input Data Restrictions Maximum Function Data Length Allowed Allowed 9 Digits 9 Digits 1 2 Digits 2 Digits Increment Same as for sel Set ected function Frequency Amplitude NOTES Inthe Amplitude function leading zeros are not counted 2 Unused or unidentifiable characters are ignored 3 Either upper or lower case letters can be used in Data messages Only the following ASCII characters are recognized by the Signal Generator A 2 az 0 9 LF Ali other characters including spaces are ignored EXAMPLE 1 CONTROLLER S TALK ADDRESS FR123 4MZ AP 10DM AMS4 END OF SIGNAL STRING GENERATOR S Set frequency Set Amplitude Set Amplitude MESSAGE LISTEN ADDRESS to 123 4 MHz to 10 dBm Modulation Off EXAMPLE 2 CONTROLLER S APIS10DB UP UPUP UP TALK ADDRESS ay is a END OF SIGNAL Set Amplitude Step Up Step Up STRING GENERATOR S increment In this case in this case MESSAGE LISTEN ADDRESS to 10 dB one increment multiple of amplitude increments of amplitude Figure 3 10 Data Message Examples 3 26 Model 8656A Receiving the Data Message Cont d A complete list of ASCII characters with conver sions to binary octal decimal and hexadecimal is provided in Table 3 10 3 24 Sending the Data Message The Signal Generator does not have the capability to talk therefore it cannot send Data messages 3 25 Receiving the Trigger Message The Signal Genera
129. y a listener never talker and therefore only its HP IB listen ad dress can be selected This HP IB address is switch selectable through five miniature rocker switches located inside the Signal Generator on the Microprocessor Memory HP IB Assembly A11 These switches provide the means to select one of 31 valid HP IB addresses 00 through 30 HP IB addresses greater than 30 decimal are invalid Refer to Table 2 2 for the allowable HP IB address codes Listed are the valid address switch settings and the equivalent ASCII character and decimal value When the instrument is shipped from the factory the HP IB address is preset to 07 decimal In binary this is 00111 the ASCII equivalent character is an apostrophe This pre set address is shown shaded in Table 2 2 The bottom cover of the Signal Generator will have to be removed to gain access to the HP IB switches The following procedure describes how to change the settings of the HP IB address switches NOTE The HP IB address stored in memory will only change when the instrument is powered up or reset Therefore the in strument must be unplugged or reset once the settings of the HP IB address switches have been changed otherwise the stored HP IB address will remain unchanged a Remove the bottom cover from the Signal Generator by first removing the two screws used to secure the strap handle to each side of the instru ment Next remove the front and rear caps
130. y be selected when the AM key is pressed if no other source has been selected The step up and step down keys associated with the AM function permit the percentage of AM depth to be changed by the value stored in the internal AM depth increment register The value of the AM depth increment initially stored is 1 This is its minimum value Its maximum value is lt 99 The percentage of AM depth will be changed once for each keystroke or repeatedly if either key remains pressed The FM key is one of the four main function keys It is used in conjunction with the SOURCE keys numeric entry keys and UNITS entry keys to enter frequency modulation parameters In addition it is used in conjunction with the INCR SET key to enter FM peak deviation frequency increment values If the percentage of AM depth is being dispiayed when the FM key is pressed the MODULATION Display will be updated to show the FM peak deviation frequency The default modulation source internal I kHz will automati cally be selected when the FM key is pressed if no other source has been selected The step up and step down keys associated with the FM function permit the FM peak deviation frequency to be changed by the value stored in the internal FM peak deviation frequency increment register The value of the FM peak deviation frequency increment initially stored is 1 0 kHz Its minimum value is 0 1 kHz and its maximum value is lt 99 kHz The FM peak deviation frequency wi
131. y will clear the error condition or pressing one of the following keys will automatically adjust the FM peak deviation frequency to the maximum frequency possible for that frequency band 3 39 Operation Operation Comments Cont d Related Instructions 3 40 Model 8656A Frequency Cont d Carrier Frequency MHz 0 1 123 5 123 5 247 247 494 494 990 The carrier frequency increment is rejected if it is not a multiple of 100 Hz or 250 Hz Frequency function will remain selected until a One of the three remaining functions is selected b One of the STORE RECALL DISPLAY keys is pressed c The instrument is reset or unplugged Frequency Coarse and Fine Tune Frequency Up Down Model 8656A Description Keystroke Sequence Example Keys and Indications Comments Operation Frequency Coarse and Fine Tune This instruction details how to quickly tune the carrier frequency in decade steps using the step up and step down keys associated with the carrier frequency function This feature is enabled by pressing either the COARSE TUNE or FINE TUNE key Pressing either key will increase COARSE TUNE or decrease FINE TUNE the carrier frequency tuning value by a factor of 10 Pressing the step up key will then increase the carrier frequency by the newly selected carrier frequency tuning value while pressing the step down key will decrease the carrier ferquency This f
132. z 0 002 input Rear Panel frequency standard at a level 50 15 Vrms into 50 ohms Frequency Switching Speed lt 2 seconds to be within 100 Hz of selected frequency SPECTRAL PURITY SSB o Noise CW only Offset 0 1 te 123 5 te 247 te 494 to from 123 5 MHz 247 MHz 494 MHz 990 MHz Carrier dBc Hz dBe Hz dBc Hz dBe Hz 20 kHz lt 115 lt 127 lt 121 lt 115 500 kHz lt 125 lt 135 lt 131 lt 125 SSB P NOISE in 1Hz BW db BELOW CARRIER 10 107 105 19 107 OFFSET FROM CARRIER Hz Typical SSB o Noise fo 450 MHz OUTPUT SWR lt 2 0 1 to 990 MHz and lt 13 dBm lt 1 5 1 0 to 990 MHz and lt 5 dBm Impedance 50 ohms nominal Reverse Power Protection protects Signal Generator from application of up to 50 watts of RF power to 990 MHz into RF OUTPUT connector de voltage cannot exceed 25V OUTPUT POWER dBm 0 1 250 500 750 1000 OUTPUT FREQUENCY MHz Typical maximum power output versus frequency output set to 17 dBm MODULATION Amplitude and Frequency Modulation External Sensitivity 1V peak for indicated accuracy Front panel annunciators indicate application of 1V peak signal 15 External Modulation Input front panel BNC ac coupled 600 ohms Modulating Signal Output internal modulating signal is provided at the front panel BNC connector at 1V peak 5 into 600 ohm resistive load Digital FM Modulation will accept digital unsquelching signals Sag of resul

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