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1. INSTRUCTION BK PRECISION MANUAL Model 4040A MANUAL DE INSTRUCCI N MODELO 4040A 20 MHz SWEEP FUNCTION GENERATOR with FREQUENCY COUNTER AEE IRF pee Ti f 555 Jij ie K 55355 ll 20 MHz GENERADOR DE BARRIDO FUNCIONES CON CONTADOR DE FRECUENCIA BK EAMAICIAA RLT T ALLTA TEST INSTRUMENT SAFETY WARNING Normal use of test equipment exposes you to a certain amount of danger from electrical shock because testing must sometimes be performed where exposed voltage is present An electrical shock causing 10 milliamps of current to pass through the heart will stop most human heartbeats Voltage as low as 35 volts dc or ac rms should be considered dangerous and hazardous since it can produce a lethal current under certain conditions Higher voltages pose an even greater threat because such voltage can more easily produce a lethal current Your normal work habits should include all accepted practices to prevent contact with exposed high voltage and to steer current away from your heart in case of accidental contact with a high voltage You will significantly reduce the risk factor if you know and observe the following safety precautions 1 Don t expose high voltage needlessly Remove housings and covers only when necessary Turn off equipment while making test connections in high voltage circuits Discharge high voltage capacitors after removing power 2 If possible familiarize yourself with the equipment bei2. Considerations 1 Make sure the tone burst and entire off period is viewed when setting the repetition rate The visible portion of the off period could be incorrectly interpreted as the entire off period To avoid this error use a low sweep speed on the oscilloscope adjusted to view the tone burst off period and the beginning of a second tone burst 2 The BURST WIDTH control does not interact with the SWEEP TIME control and will not affect the repetition rate However both controls affect the tone burst width Since the BURST WIDTH control adjusts the duty cycle percentage of repetition rate cycle in which tone burst is produced any subsequent adjustment of the SWEEP TIME control affects the tone burst width as well as the off period When setting the tone burst width to a specific time period adjust the SWEEP TIME control first then the BURST WIDTH control 3 The tone burst output signal is always in full cycles or half cycles Note that as the BURST WIDTH control is adjusted slowly the tone burst is increased or decreased on half cycle increments This allows synchronization of the waveform for oscilloscope viewing and eliminates transients and frequency components not harmonically related to the frequency being gated This feature is applicable to internal or external tone burst operation OPERATING INSTRUCTIONS AM OPERATION The output of Model 4040A can be amplitude modulated either by the internal 1 kHz signal or b
3. The Model 4040A can be operated as a voltage controlled generator by using an external control voltage applied to the VCG MOD INPUT jack 12 The externally applied voltage OPERATING INSTRUCTIONS will vary the frequency which is pre selected by the range switches and the frequency controls Applying approximately 10 V with the COARSE control at full clockwise decreases the output frequency by about 100 times a 100 1 ratio 1 Select the desired frequency range and waveform 2 Set the starting frequency with the COARSE control Apply a positive DC voltage to the VCG MOD INPUT jack 12 to decrease the frequency A voltage from 0 to 10 V will cause the frequency to decrease by a factor of 100 if the COARSE frequency control is set at maximum CW rotation For example if the starting frequency is 100 kHz applying 10 V will change the output frequency to 1 kHz 3 To operate the function generator as a sweep generator apply a positive going ramp signal to the VCG MOD input jack As the ramp voltage increases the frequency decreases The rate of sweep can be adjusted by varying the frequency of the ramp signal 4 Specific frequencies can be selected by applying a fixed dc voltage to the VCG MOD INPUT jack or the frequencies can be stepped by applying a stepped dc voltage 5 Do not apply more than 15 volts dc or dc ac peak to the VCG MOD INPUT jack Inputs of more than 15 volts will not cause any further shift in the frequen
4. Output are nA 17 Voltage Controlled Frequency Operation ee 17 Sweep Operation ieies ii hen e 18 Use of Frequency Counter with External Signals 18 Output Protection Considerations eee eeeee eens 19 Function Generator Applications Guidebook 19 MAINTENANCE scenvits nies nude tenes castes eens betes 20 Fuse Replacement ec eeeec ce eeeeeeeaeeeeeaneeeeeaa 20 Instrument Repair Service seereis nintsen 20 Customer SUpPPOLt uren aa o eia Ee a o Ea 21 WARRANTY SERVICE INSTRUCTIONS 22 LIMITED TWO YEAR WARRANTY senere 23 SPANISH MANUAL eee neeeeeeceeeeeaanneeeeeeeeees 25 INTRODUCTION The B amp K Precision Model 4040A Sweep Function Generator is a versatile signal source which combines several functions into one unit waveform generation pulse generation through variable symmetry and frequency sweep Additionally the instrument provides the added convenience of a built in frequency counter This permits more accurate determination of output frequency than is possible with a simple calibrated dial Coarse and fine tuning controls permit precision stability of the output frequency The internal frequency counter can also be used to measure external frequencies The five digit frequency counter displays the generator output frequency or external signals from 5 to 30MHz With this versatility the unit has a vast number of applications in both analog and digital electronic
5. To gain a working familiarity with the unit it is recommended that it be connected initially to an oscilloscope so that the effects of the various controls on the output waveforms can be observed Use this manual as required for reference until becoming accustomed to the operating procedures FREQUENCY AND WAVEFORM SELECTION W Initially verify that the DUTY CYCLE 2 CMOS LEVEL 3 DC OFFSET 4 20dB 5 and SWEEP EXT INT 22 and AM FM 35 switches are in the released position This will produce a symmetrical waveform unaffected by the sweep generator and other controls Plug the unit into an appropriate power source and turn it on by depressing the POWER switch 1 Select the desired waveform SINE SQUARE or TRIANGLE by depressing one of the FUNCTION switches 9 Phase relationships of the waveforms are shown in Fig 2 Select the frequency of the waveform by depressing one of the RANGE switches 6 The output frequency is displayed along with the appropriate measurement units KHz or Hz 31 on the LED display 11 5 Rotate the COARSE 28 frequency control to quickly set the output frequency to the approximate desired value The FINE 26 frequency control can then be used to easily set the output to the specific desired value The frequency selected is available at the OUTPUT jack 13 In addition a digital signal either TTL or CMOS is available at the TTL CMOS jack 15 refer to the T
6. purchase B amp K Precision Corp will without charge repair or replace at its option defective product or component parts Returned product must be accompanied by proof of the purchase date in the form of a sales receipt To obtain warranty coverage in the U S A this product must be registered by completing a warranty registration form on www bkprecision com within fifteen 15 days of purchase Exclusions This warranty does not apply in the event of misuse or abuse of the product or as a result of unauthorized alterations or repairs The warranty is void if the serial number is altered defaced or removed B amp K Precision Corp shall not be liable for any consequential damages including without limitation damages resulting from loss of use Some states do not allow limitations of incidental or consequential damages So the above limitation or exclusion may not apply to you This warranty gives you specific rights and you may have other rights which vary from state to state B amp K Precision Corp 22820 Savi Ranch Parkway Yorba Linda CA 92887 www bkprecision com 714 921 9095 23 TEST INSTRUMENT SAFETY continued from inside front cover 6 Some equipment with a two wire ac power cord including some with polarized power plugs is the hot chassis type This includes most recent television receivers and audio equipment A plastic or wooden cabinet insulates the chassis to protect the customer When the cabinet is re
7. BOOK B K Precision offers a Guidebook to Function Generators which describes numerous applications for this instrument including hook up details It also includes a glossary of function generator terminology and an explanation of function generator circuit operation It maybe downloaded for free off our website at www bkprecision com MAINTENANCE WARNING The following instructions are for use by qualified service personnel only To avoid electrical shock do not perform servicing other than contained in the operating instructions unless you are qualified to do so Remember that ac line voltage is present on line voltage input circuits any time the instrument is plugged into an ac outlet even if turned off Always unplug the function generator before performing service procedures FUSE REPLACEMENT 1 Locate the fuse holder on the input line receptacle 2 Remove the fuse holder and replace the fuse with an equal value fuse INSTRUMENT REPAIR SERVICE Because of the specialized skills and test equipment required for instrument repair and calibration many customers prefer to rely upon B K PRECISION for this service We maintain a network of B K PRECISION authorized service agencies for this purpose To use this service even if the instrument is no longer under warranty follow the instructions given in the WARRANTY SERVICE INSTRUCTIONS portion of this manual There is a nominal charge for instruments out of warranty AC LI
8. Internal External Modulation Ratio 0 To 100 INT Modulation 1kHz EXT Modulation DC to 500KHz EXT Sensitivity Less than 10V p p for 100 modulation FM MODULATION CHARACTERISTICS Source Internal External Deviation 0 to 5 INT Modulation 1kHz EXT Modulation EXT Sensitivity DC to 500kHz Less than 10V p p for 100 modulation BURST CHARACTERISTICS Source Internal External Burst Width Continuously variable from 5 to 90 of internal gating frequency Repetition Rate Burst Frequency FREQUENCY COUNTER Accuracy Time Base Accuracy Display External Input Frequency Resolution Sensitivity Impedance AC INPUT 0 5Hz to 50Hz internal or DC to 500kHz external Determined by the main generator frequency setting Tone burst is in integral cycles of frequency being gated Time Base Accuracy 1 count 10PPM 23 C 5 C 5 digit LED 5Hz to 30MHz 0 1 1 10 100 1 kHz lt 25 mV rms 1 MQ 100 Pf 120 230VAC 10 50 60Hz internal jumper selectable DIMENSIONS H x W x D 10 1 2 x 5 1 2 x 12 3 8 26 67cm x 13 97cm x 31 43cm WEIGHT 5 3 Ib 2 4 kg ACCESSORIES Output Cable BNC to Alligator Clips Instruction Manual NOTE See Maintenance section for AC Line Selection and fuse information Specifications and information are subject to change without notice Please visit www bkprecision com for the most current product information T CONTROLS AND INDICATORS F
9. NE SELECTION This instrument can operate on 120 or 230 VAC source at 50 or 60 Hz The internal jumper allows you to select the line voltage Before connecting the power plug to an AC line outlet be sure to check that voltage selector plug is set in the correct position corresponding to the line voltage in your location and the fuse rating is as shown in the table Line Voltage Fuse 120V 250 V0 2 A 230V 250 V0 1A 20 CUSTOMER SUPPORT 1 800 462 9832 B K Precision offers courteous professional technical support before and after the sale of their test instruments The following services are typical of those available from our toll free telephone number Technical advice on the use of your instrument Technical advice on special applications of your instrument Technical advice on selecting the best instrument for a given task Information on optional accessories for your instrument Information on instrument repair and recalibration services Replacement parts ordering Availability of service publications Information on other B K Precision instruments Requests for a new B K Precision catalog The name of your nearest B K Precision distributor Call toll free 1 800 462 9832 Monday through Thursday 8 00 A M to 5 00 P M Friday 8 00 A M TO 11 30 A M Pacific Standard Time Pacific Daylight Time summer 21 BK CISION ji Service Information Warranty Service Please return t
10. RONT PANEL Refer to Fig 1 1 POWER Switch Turns power on and off 2 DUTY CYCLE Switch When engaged enables operation of DUTY CYCLE control 7 3 CMOS LEVEL Switch When engaged changes the TTL signal to CMOS signal at the TTL CMOS jack and enables operation of CMOS LEVEL Control 8 4 DC OFFSET Switch When engaged enables operation of the DC OFFSET control 11 5 20dB Switch When engaged the signal at the OUTPUT jack is attenuated by 20dB 6 RANGE Switch Selects output frequency range Eight ranges from 2Hz to 20MHz Switch indicates maximum frequency of range and is adjusted with COARSE FREQUENCY control to 0 1 times the maximum For example if the 200 kHz range is selected the output frequency can be adjusted from 20kHz to 200kHz 7 DUTY CYCLE Control Activated by the DUTY CYCLE Switch 2 Rotation from center position adjusts the duty cycle of the main OUTPUT signal and TTL CMOS signal 8 CMOS LEVEL Control Rotating this control clockwise increases the amplitude of the CMOS signal at the TTL CMOS jack 9 FUNCTION Switch Selects sine square or triangle waveform at OUTPUT jack 10 11 12 13 14 15 16 OUTPUT LEVEL Control Controls the amplitude of the signal at the OUTPUT jack Output level can be decreased by approximately 20dB with this control DC OFFSET Control Activated by the DC OFFSET Switch 4 Clockwise rotation from center changes the DC offset in a positive directi
11. TL CMOS OUTPUT section of this manual TTL a ame eae moe Seek BS Figure 2 Output Waveform and Phase Relationship OPERATING INSTRUCTIONS 6 Adjust the amplitude of the output as desired using the OUTPUT LEVEL control 10 Rotation of this control varies the amplitude from maximum to 20dB below maximum An additional attenuation of 20dB is available by pushing in the 20dB switch 5 The attenuation factors can be combined for a total of 40dB The maximum signal level is 10V p p into 50Q A DC component can be added to the output signal by pushing in the DC OFFSET switch 4 to enable operation of the DC OFFSET control 11 Rotation of this control adds a positive or negative DC component to the output signal The DC component introduced is independent of the OUTPUT LEVEL control and can be varied by 10 volts open circuited or 5 volts into 50Q The DC Offset does not affect the TTL CMOS output jack The effect of DC OFFSET is shown in Fig 3 Considerations l Counterclockwise rotation of the COARSE frequency control decreases the output frequency to approximately one tenth of the maximum for the range selected 10 1 For example if the 10K range is selected and the COARSE frequency control is set to full counterclockwise the output frequency is approximately 1 kHz It is advisable to set the FINE frequency control to the approximate center of its rotation before setting the COARSE frequency
12. cessary Training in CPR cardio pulmonary resuscitation first aid is highly recommended 24 BK PreGrsrore 22820 Savi Ranch Parkway Yorba Linda CA 92887 2005 B amp K Precision Printed in U S A
13. control This assures that the FINE control will not reach its limit while trying to finalize the frequency setting 12 10V b A Ea A Zero OC Offset With Maomum Vv 4 Signai 10W AMM WN 8 Offset Limits Without Clipping OV Positive Negative OC Offset OC Offset 10V m eo C Excessive Offset ov e AN Te O Negatve OC Offset DC Offset Figure 3 Use of DC OFFSET Control 3 The FINE frequency control provides approximately 5 frequency deviation from the COARSE control setting This provides vernier adjustment to easily set the frequency to a precise value OPERATING INSTRUCTIONS 4 When the 2 Hz range is selected the gate time is 10 seconds and the display is updated once every 10 seconds The result of a frequency change will not be displayed until 10 seconds later Adjust the frequency in progressively smaller steps waiting for the display to update until the desired frequency is obtained 5 When outputting square waves or when using the TTL output Pulse terminate the cable into 50Q to minimize ringing Also keep Square cables as short as possible 6 Remember that the output signal swing of the generator is limited to 10 volts open circuited or 5 volts into 50Q and applies to the combined peak to peak signal and DC offset Clipping occurs slightly above these levels Fig 3 illustrates the Pa a ies various operating conditions encountered when
14. cy and could cause damage to the generator OPERATING INSTRUCTIONS SWEEP OPERATION 1 Select LINEAR sweep by leaving the SWEEP LIN LOG switch 23 in the released position or select LOG sweep by engaging the SWEEP LIN LOG switch 2 Rotate COARSE FREQUENCY Control to minimum CCW to obtain maximum sweep width 3 Engage the RUN SET switch to adjust the start and stop sweep frequencies 4 With the START STOP switch set to START released position adjust the starting frequency of the sweep by adjusting the START control and observing the counter To achieve a start frequency that is gt 30 of range use both SWEEP START and COURSE FREQUENCY control 5 Engage the START STOP switch to the STOP position and adjust the stop sweep frequency by adjusting the STOP control 6 Release the RUN SET switch for sweep operation The sweep rate can be adjusted with the SWEEP TIME control Clockwise rotation increases the sweep rate If the output of the circuit to be tested is connected to the vertical scope input and the GCV output to the horizontal setting the scope to X Y mode produces the amplitude vs frequency plot However note that switching to LOG sweep still produces a linear display on the scope This is because the horizontal sweeping signal the internal log ramp also becomes logarithmic when the sweep does To view a true logarithmic graph put the scope back in time base operation and use the Sweep output solely as a scope
15. esolution Tuning Range Variable Duty Cycle Operating Modes Frequency Stability Sine Square Triangle Pulse Ramp 0 2Hz to 20MHZ in 8 ranges Coarse 10 1 Fine 5 of Coarse Setting 15 85 15 Continuously Variable Normal Sweep VCG AM FM Burst The output will change less than 0 09 over 15 minutes after 1 hour warmup OUTPUT CHARACTERISTICS Impedance 50Q 10 Level 20V p p Open circuit 10V p p into 50Q Amplitude Control Attenuation Dc Offset Sine Wave Distortion Flatness to 1OMHz Variable 20dB range typical 20dB 1dB Preset 0 V typical Variable 10V open circuit 5V into 50Q 0 1Hz to 10OKHz lt 3 5 0 45 dB 10Hz to 8MHZ 20 2 0 dB 8MHZ to 20MHZ 3Vp p Square Wave Symmetry Rise Time Overshoot amp Undershoot TRIANGLE WAVE Linearity TTL OUTPUT Level Rise Time Duty Cycle CMOS OUTPUT Max Frequency Level Rise Time lt 2 0 2Hz to 100kHz lt 30ns Typical lt 5 gt 98 to 100kHz 0 8V to 2 4V lt 20 nS 50 typical 2MHz 4V to 14V 0 5V p p continuously variable lt 120nS VCG Voltage Controlled Generator INPUT Input Voltage Impedance 0 10V 1V causes a 100 1 frequency change 10kQ 5 SPECIFICATIONS SWEEP OPERATION Mode LIN LOG Width 100 1 Continuously variable Rate 20mS to 2 sec continuously variable Sweep Output 0 to 2V Start Stop Frequencies Adjustable AM MODULATION CHARACTERISTICS Source
16. he product in the original packaging with proof of purchase to the address below Clearly state in writing the performance problem and return any leads probes connectors and accessories that you are using with the device Non Warranty Service Return the product in the original packaging to the address below Clearly state in writing the performance problem and return any leads probes connectors and accessories that you are using with the device Customers not on open account must include payment in the form of a money order or credit card For the most current repair charges please visit www bkprecision com and click on service repair Return all merchandise to B amp K Precision Corp with pre paid shipping The flat rate repair charge for Non Warranty Service does not include return shipping Return shipping to locations in North American is included for Warranty Service For overnight shipments and non North American shipping fees please contact B amp K Precision Corp B amp K Precision Corp 22820 Savi Ranch Parkway Yorba Linda CA 92887 www bkprecision com 714 921 9095 Include with the returned instrument your complete return shipping address contact name phone number and description of problem 22 Limited Two Year Warranty B amp K Precision Corp warrants to the original purchaser that its products and the component parts thereof will be free from defects in workmanship and materials for a period of two years from date of
17. itch 4 The amount of deviation can be varied by rotating the MODU LATION control External 1 Set the carrier frequency using the main FREQUENCY controls and RANGE switches 2 Engage the MODULATION ON switch and release the MODU LATION FM AM switch 3 Place the EXT MODULATION switch in the released position 16 4 Connect a suitable modulation signal to the VWCG MOD INPUT jack on the front panel 5 Adjust the amplitude and frequency of the external signal as required Typically a signal less than 10V p p will provide 10 modulation of the carrier TTL CMOS OUTPUT The TTL CMOS output jack provides a fast rise time square wave output Either a fixed TTL or a variable CMOS output level is available The output is positive with respect to ground and can be used as an external sync pulse for oscilloscopes or as a variable frequency signal source for exercising logic circuits Because of the fast rise time of this output cable length should be minimized to limit ringing and overshoot 1 Select the desired frequency range and adjust the frequency controls as required The OUTPUT LEVEL and DC OFFSET controls have no effect on the signal at the TTL CMOS jack 2 When the CMOS LEVEL switch 3 is released a TTL signal is output at the TTL CMOS jack Select a CMOS signal by engaging the CMOS LEVEL switch and adjust the level of the signal by rotating the CMOS LEVEL control 8 VOLTAGE CONTROLLED FREQUENCY OPERATION
18. ment of the starting and stopping sweep frequencies The actual adjustment is performed by the SWEEP START and SWEEP STOP controls 29 and 27 START STOP selection is enabled only when the SET RUN switch 21 is set to SET RUN SET Switch Selects sweep set or sweep run operation In the SET position the starting or ending sweep frequency is continuously present at the output In the RUN position the generator sweeps between the low and the high frequencies at a rate set by the SWEEP TIME control SWEEP EXT INT Switch When engaged INT enables the sweep mode of operation Sweep rate is controlled by SWEEP TIME control 25 and sweep length is controlled by the SWEEP STOP control 27 and the start frequency is controlled by the SWEEP START control 29 When released EXT allows external control of generator output frequency by a DC voltage input at the VCG MOD INPUT jack 12 SWEEP LIN LOG Switch When engaged LOG selects logarithmic sweep characteristic and when released LIN selects a linear sweep characteristic CNTR INT EXT Switch Selects the input source for the counter input SWEEP TIME Control In sweep mode rotation determines amount of time to sweep from the start frequency to the stop frequency FINE FREQUENCY Control Vernier adjustment of the output frequency for ease of setting frequency 10 27 28 29 30 31 32 33 34 35 36 SWEEP STOP Control Adjusts the ending sweep freq
19. moved for servicing a serious shock hazard exists if the chassis is touched Not only does this present a dangerous shock hazard but damage to test instruments or the equipment under test may result from connecting the ground lead of most test instruments to a hot chassis To test hot chassis equipment always connect an isolation transformer between the ac outlet and the equipment under test The B K Precision Model TR 110 or 1604 Isolation Transformer or Model 1653 or 1655 AC Power Supply is suitable for most applications To be on the safe side treat all two wire ac equipment as hot chassis unless you are sure it has an isolated chassis or an earth ground chassis 7 On test instruments or any equipment with a 3 wire ac power plug use only a 3 wire outlet This is a safety feature to keep the housing or other exposed elements at earth ground 8 B K Precision products are not authorized for use in any application involving direct contact between our product and the human body or for use as a critical component in a life support device or system Here direct contact refers to any connection from or to our equipment via any cabling or switching means A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause failure of that device or system or to affect its safety or effectiveness 9 Never work alone Someone should be nearby to render aid if ne
20. ng tested and the location of its high voltage points However remem ber that high voltage may appear at unexpected points in defective equipment 3 Use an insulated floor material or a large insulated floor mat to stand on and an insulated work surface on which to place equipment and make certain such surfaces are not damp or wet 4 Use the time proven one hand in the pocket technique while handling an instrument probe Be particularly careful to avoid contacting a nearby metal object that could provide a good ground return path 5 When testing ac powered equipment remember that ac line voltage is usually present on some power input circuits such as the on off switch fuses power transformer etc any time the equipment is connected to an ac outlet even if the equipment is turned off continued on inside back cover Instruction Manual for Model 4040A 20 MHz SWEEP FUNCTION GENERATOR with FREQUENCY COUNTER BX PRECIO 22820 Savi Ranch Parkway Yorba Linda CA 92887 TABLE OF CONTENTS TEST INSTRUMENT SAFETY inside front cover INTRODUCTION 0000 eee a A A 5 SPECIFICATIONS ndoa ae E Aaa iiia 6 CONTROLS AND INDICATORS uo eee cere 8 OPERATING INSTRUCTIONS ooeec 11 Frequency and Waveform Selection eeee 11 Duty Cycle Control 7a r 2s eves eae aaar ENa Ea 13 Burst Opera Oe a a oss EN ae teak Ea 14 AM Operation sicdecsscteceeacndhteGeae bethe diets eaS 15 FM Operation neran na ee eee tee 16 TIL CMOS
21. nnecting the output of the function generator to a voltage in the equipment under test The following protective measures are strongly recommended The user should understand the equipment under test well enough to identify valid signal injection points e g the base of a transistor a logic input of a gate etc The voltage at valid signal injection points is rarely high enough to damage the instrument If in doubt about the safety of a signal injection point measure the voltage present at the intended point of signal injection before connecting the function generator output to that point When applying the main output of the function generator to a circuit point containing a dc level adjust the DC OFFSET control so that the dc level at the main output matches the circuit voltage Connect the TTL output only to TTL level circuits Connect the CMOS output only to CMOS circuits Measure the Vcc of the 19 OPERATING INSTRUCTIONS 150 0 2 W TTL FUNCTION GENERATOR 5 6V vane TTL OUTPUT iW CIRCUIT GROUND Figure 7 Circuit for Protection of TTL Output circuit under test and adjust the CMOS LEVEL control as instructed in the manual When the function generator is used by students or other inexperienced users the circuit shown in Fig 7 could be added into your TTL output probe or test clip set It will protect the TTL output of the generator against external voltages up to 20 volts FUNCTION GENERATOR APPLICATIONS GUIDE
22. on while counterclockwise rotation from center changes the DC offset in a negative direction VCG MOD INPUT Jack Controlled by MODULATION OFF ON Switch 33 When MODULATION OFF is selected jack is the Voltage Controlled Generator input and permits external control of generator output frequency by a DC voltage input at this jack A positive voltage will decrease frequency When MODULATION ON is selected jack becomes modulation input source OUTPUT Jack Waveform selected by FUNCTION Switch as well as the superimposed DC OFFSET voltage is available at this jack BURST INPUT Jack Input for external gating signal for Burst operation TTL CMOS Jack TTL or CMOS square wave depending on the position of the CMOS LEVEL switch 3 is output at this jack This output is independent of the OUTPUT LEVEL and DC OFFSET controls EXT COUNTER INPUT Jack Input for external frequency measurements 32 33 34 35 1 23 4 3 6 TF 8 9 10 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 Figure 1 Model 4040A Front Panel 17 BURST WIDTH Control Adjusts the duty 19 BURST OFF ON Switch Selects external or cycle of the internal burst gate internal burst gate Continuous output is obtained 18 MODULATION Control Adjusts the with switch in the OFF position and no external percentage of AM or FM modulation burst gate is applied CONTROLS AND INDICATORS 20 21 22 23 24 25 26 START STOP Switch Enables adjust
23. r output is switched on and off gated either by an internally generated signal or by an externally applied signal Both the repetition rate and the duty cycle are variable Fig 5 illustrates the type of waveform generated and summarizes the control settings used to obtain the desired waveform Internal Triggering 1 Select the waveform to be gated by pushing in the appropriate FUNCTION switch Display the output of the generator on an oscilloscope 2 Adjust the frequency amplitude symmetry and dc offset of the signal by using the main generator controls 3 Enable the burst mode by pushing in the BURST ON switch 4 Set the repetition rate of the burst with the SWEEP TIME control 5 Adjust the tone burst duty cycle or adjust the tone burst width to a specific time period with the BURST WIDTH control External Triggering 1 Select the waveform to be gated by pushing in the appropriate FUNCTION switch on the front panel 2 Adjust the frequency amplitude symmetry and dc offset of the signal by using the main generator controls 14 Frequency ot Tone Burst Tone Of Period Set by FREQ Controis and Burst RANGE Pa Adjust Tone Burst Duty Cycie Tone Burst vs Off Period with BURST WIDTH Control Adjust Repetition Rate with SWEEP TIME Control Figure 5 Tone burst generator output waveform 3 With BURST ON OFF switch in OFF position apply a TTL gating signal of the proper width to the front panel BURST INPUT jack
24. s in the engineering manufacturing servicing educational and hobbyist fields The heart of the function generator is a VCG voltage controlled generator that produces precision sine square or triangle waves over the 0 2Hz to 20MHz range This encompasses subaudible audio ultrasonic and RF applications A continuously variable dc offset allows the output to be injected directly into circuits at the correct bias level The sweep generator offers linear or log sweep with variable sweep rate and adjustable sweep time Front panel controls allow the start and stop frequencies to be set Burst operation enables the output to be gated by an internal adjustable signal or by an externally applied signal Variable symmetry of the output waveform converts the instrument to a pulse generator capable of generating rectangular waves or pulses ramp or sawtooth waves and slewed sine waves The output can be either amplitude modulated or frequency modulated Modulation can be by a 1 kHz internal adjustable signal or by an externally applied signal In addition to the above features an external voltage may be used to control operating frequency This is useful in situations where an externally controlled frequency is desirable Many functions can be operated simultaneously making possible such complex outputs such as gated pulse trains with external or internal sweep SPECIFICATIONS FREQUENCY CHARACTERISTICS Waveforms Range R
25. trigger Use the scope s linear time base as a horizontal deflection source 18 USE OF FREQUENCY COUNTER WITH EXTERNAL SIGNALS The frequency counter display in the Model 4040 is normally used to monitor the internally generated output However it can also be used as a stand alone frequency counter up to 30 MHz em Set the CNTR INT EXT switch to EXT 2 Apply the signal to be measured to the EXT CNTR INPUT jack on the front panel 3 Obtain the desired display resolution by selecting the appropriate gate period using the GATE pushbutton switch The resolution obtained with each of the four gate settings is as follows given an input signal of exactly 2 KHz Gate Setting Reading Indicator 0 01S 2 0 KHz 0 1S 2 00 KHz 1S 2000 Hz 10S 2000 0 Hz OUTPUT PROTECTION CONSIDERATIONS Use care when connecting the function generator output to a signal injection point Excessive voltage at the point of signal injection of the function generator can cause internal damage Under normal operation the generator output should never be connected to an external voltage other than low dc values that can be matched with the DC OFFSET control The Model 4040 is overload protected so that shorting the output even continuously will not cause damage A fuse has been added in series with the OUTPUT jack to help protect the instrument from damage by connection to excessive external voltage Damage of this type usually occurs by accidentally co
26. uency COARSE FREQUENCY Control Coarse adjustment of the output frequency from 0 1 to 1 times the selected range SWEEP START Control Adjusts the starting sweep frequency GATE LED Indicates when the frequency counter display is updated When the 200K through 20M ranges are selected the LED will flash 10 times per second every 0 1 seconds When the 20 through 20K ranges are selected the LED will flash once every second and when the 2 range is selected the LED will flash every 10 seconds As the LED turns off the display is updated Hz and KHz LED Indicates whether the counter is reading in Hz or KHz COUNTER DISPLAY Displays frequency of internally generated waveform or external signal when CNTR EXT is selected MODULATION ON OFF Switch Enables or disables modulation of the generator MODULATION EXT INT Switch Selects whether generator modulation is from the internal 1 KHz source or from a signal applied to the VCG MOD INPUT jack MODULATION FM AM Switch Selects Frequency modulation or Amplitude modulation GCV OUTPUT Located on back panel Generator control voltage output Voltage is proportional to the generator frequency When Sweep mode is selected sweep voltage is present at this jack for connection to an oscilloscope OPERATING INSTRUCTIONS The B amp K Precision Model 4040A Sweep Function Generator is a versatile instrument capable of producing a variety of output waveforms over a broad range of frequencies
27. using the DC Triangle offset If the desired output signal is large or if a large DC offset o ese Nee is required an oscilloscope should be used to make sure that the desired signal is obtained without undesirable clipping DUTY CYCLE CONTROL Slewed oo a ka Sine Sine The DUTY CYCLE control can be used to alter the symmetry of i a the output waveform to produce waveshapes such as those shown in Fig 4 For a square wave symmetry variation amounts to changing the duty cycle ratio of high to low time effectively converting the instrument into a pulse generator For a triangle wave the result is Figure 4 Effects of Symmetry Variation a ramp and with a sine wave a distorted waveshape called a slewed 2 Engage the DUTY CYCLE switch 2 and adjust sine is produced The Model 4040 provides for symmetry variation the DUTY CYCLE control 7 for the desired from 15 to 85 waveshape Clockwise rotation from center results in an increase in square wave duty cycle and 1 Select the waveform desired either SINE SQUARE or changes the sine and triangle waves as shown in the TRIANGLE top waveform of each pair of Fig 4 Counter clockwise rotation results in the bottom waveform in each pair 13 OPERATING INSTRUCTIONS 3 Varying the duty cycle setting results in a slight change in frequency Adjust the COARSE and FINE frequency controls as required BURST OPERATION In gated burst mode of operation the generato
28. y an external signal applied to the VCG MOD INPUT jack Internal 1 Set the carrier frequency using the main FREQUENCY controls and RANGE switches 2 Engage the MODULATION ON and AM MODULATION switches Engage the INT MODULATION switch 4 Set the percent of modulation by rotating the MODULATION control Modulation can be set in excess of 100 Fig 6 shows the appearance of a carrier modulated by a sine wave and the quantities A and B which are used in measuring percentage of modulation The formula is w Percent modulation 2B A x 100 Where A unmodulated carrier level B modulation depth External 1 Set the carrier frequency using the main FREQUENCY controls and RANGE switches 2 Engage the MODULATION ON and AM MODULATION switches 15 OPERATING INSTRUCTIONS y i Figure 6 Examples of AM modulation 3 Place the EXT MODULATION switch in the released position 4 Connect a suitable modulating signal to the VWCG MOD INPUT jack on the front panel 5 Adjust the modulation level as described previously FM OPERATION The output of the Model 4040 can be frequency modulated either by the internal 1 kHz internal signal or by an external signal applied to the front panel VCG MOD INPUT jack Internal 1 Set the carrier frequency using the main FREQUENCY controls and RANGE switches 2 Engage the MODULATION ON switch and release the MODU LATION FM AM switch 3 Engage the INT MODULATION sw
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