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1. A an r m E septate a car E fat zr tee gt aaa E D Ere Mec a e 5 nea me eee E Se i 5 SE E 5 3 3 CERE 3 i ud Sono cp bo EXE EIS 4 sash NEIN Det ce noone ara E e E E eu E ESSE 2 cst punc TABLE OF CONTENTS List of Hlustrations List of Tables SECTION 1 SECTION 2 SECTION 3 REV A NOV 1975 SPECIFICATION Electrical Characteristics Environmental Physical OPERATING INSTRUCTIONS Installation Front Panel Controls Connectors and Indicators Main Triggering Controls Sweep Controls Delayed Triggering Controls Front Panel Inputs Familiarization Procedure Setup Procedure Sweep Functions Triggering Functions General Operating Information Main Triggering Main Trigger Modes Main Trigger Coupling Main Trigger Source Input impedance Trigger Slope Trigger Level Selecting Sweep Rates Time Measurement Display Modes Delay Time Multiplier Delayed Sweep Triggering Mainframe Operating Modes Applications Time Duration Measurements D
2. UTE RN Effect of LEVEL control SLOPE switch on ert display 1752 05 to be displayed correct setting of the SLOPE switch is im portant to provide a display which starts on the desired slope of the input signal Trigger Level The Main Triggering LEVEL control determines the voltage level on the trigger signal at which the sweep is triggered when operating in the AUTO NORM or SINGLE SWEEP modes When the LEVEL control is set in the region the trigger circuit responds at a more positive point on the trig ger signal When the LEVEL control is set in the region the trigger circuit responds at a more negative point on the trigger signal Fig 2 4 illustrates this effect with different settings of the SLOPE switch To set the LEVEL control first select the Main Triggering MODE COUPLING SOURCE and SLOPE Then set the LEVEL control fully counterclockwise and rotate it clock wise until the display starts at the desired point Less selec tion of the triggering level is available as the trigger signal frequency exceeds 150 megahertz When operating in the Main Triggering HF SYNC Mode the LEVEL control synchronizes the trigger generator frequen cy to a subharmonic of the trigger signal frequency Trigger slope and level cannot be selected Selecting Sweep Rates The TIME DIV OR DLY TIME switch selects calibrated sweep rates for the delaying sweep DLY D Time Divi sion switch selec
3. J reesi N T TRACE SEP p TEKTRONIX 7B92A VARIABLE CALIN 0 f TIME DIV ORDLY TIME Operating Instructions 7B92A Operators SOURCE Switches Select the triggering source Selected source is indica ted by lighted pushbutton INT Trigger signal obtained internally from Ampli fier plug in unit of oscilloscope LINE Trigger signal obtained internally from the line voltage applied to the oscilloscope EXT Trigger signal obtained from an external source applied to the MAIN TRIG IN connector i 5 GP Eri 0 3 1752 17 Fig 2 3 Front panel controls and connectors REV A NOV 1975 Operating Instructions 7B92A Operators 2 4 SOURCE Switches cont EXT 10 Trigger signal obtained from an external source applied to the MAIN TRIG IN connector In this position the external signal is attenuated before it is applied to the trigger circuit Sweep Controls TIME DIV OR DLY TIME Selects the basic sweep rate for normal sweep opera tion and selects the delay time multiplied by the DE LAY TIME MULT dial setting when operating in the Alternate or Delayed sweep modes The VARIABLE control must be in the CAL knob in position for ca librated sweep rate DLY D Time Division Selects the delayed sweep rate for operation in Delay ed and Alternate sweep modes The VARIABLE con trol must be in the CAL knob in position for cali brated s
4. ger signal The LEVEL control should be set for optimum display In the High Frequency Synchronization mode the display is not necessarily stable when the TRIG D indi cator is lit 2 8 When the LEVEL control is adjusted between subharmonics of the trigger signal frequency the trigger repetition rate is below 100 megahertz or outside the frequency range select ed by the COUPLING switch or the trigger signal amplitude is inadequate the sweep free runs at the sweep rate deter mined by the TIME DIV OR DLY TIME switch NORM The NORM pushbutton provides a triggered display with the correct setting of the LEVEL control whenever an adequate trigger signal is applied The TRIG D indicator lights when the display is triggered The NORM trigger mode must be used to produce triggered displays with trigger repetition rates below about 30 hertz When the TRIG D indicator is off no trace will be displayed SINGLE SWEEP When the signal to be displayed is not re petitive or varies in amplitude waveshape or repetition rate a conventional repetitive type display may produce an un stable presentation A stable display can often be obtained under these circumstances by using the single sweep feature of this unit The single sweep mode is also useful to photo graph non repetitive or unstable displays To obtain a single sweep display of a repetitive signal first obtain the best possible display in the NORM mode Then without changing
5. goce e MR je 4 2 Z 4 gt INS T tor Tektronix Inc Beaverton Oregon 97077 P O Box 500 Serial Number irst Printing DEC 1974 070 1752 01 sae MOX Se a rea err meter neges Mere REY ze ees ME uan uendere aa ain 4 ee ee pete eae ned e ror ea se 11 T t4 i gt At IEEE e em 4 A RUE 4 8 n AS hen ene 4 D pues E e ie gt 1 seine eminent chee ae x ea re mere Rs ae MEE ety ERA MO 3 e s Os era Str um 2 wey gt pe OPE I ase Uem near ara SS A n m A ane e e s DA TM merde drm dtd gt 5 K z es Pat tate E a asi PEE Mutat amna an e T arta erar Mgr nee 2 Sac pen gt J 0 X iy des ead true 5 E E CRT 2a ESS Mer ae i gt ance a fa een 2 o Sah ADDE FUE ld murra E DM PUE
6. the display should be stable Rotate the LEVEL control counterclockwise out of the detent and adjust for a stable display Check that stable crt displays can be ob tained with the Delayed Triggering COUPLING switch set to AC and DC Disconnect the high frequency signal from the oscilloscope system 2 7 Operating Instructions 7B92A Operators GENERAL OPERATING INFORMATION Main Triggering The Main Triggering MODE COUPLING and SOURCE pushbutton switches are arranged in a sequence which places the most often used position at the top of each series of pushbuttons With this arrangement stable display can usually be obtained by pressing the top pushbuttons AUTO AC and INT When an adequate trigger signal is applied and the LEVEL control is set correctly the TRIG D indi cator will light If the TRIG D indicator is not lit 1 the LEVEL control is at a setting outside the range of the trig ger signal from the Amplifier plug in unit 2 the trigger signal is inadequate or 3 the trigger signal frequency is below the lower frequency limit of the COUPLING switch position If the desired display is not obtained with these pushbuttons other selections must be made Refer to the following discussions or the instruction manuals for the oscilloscope and Amplifier plug in unit for more information Main Trigger Modes The MODE pushbutton switch selects the mode in which the main sweep is triggered AUTO The AUTO pushbutton pr
7. IN TIME DIV oR DLY TIME S 1752 15 7B92A Features The 7B92A Dual Time Base unit provides normal delayed intensified and alternate sweep operation for Tektronix 7000 Series Oscilloscopes Calibrated sweep rates from 0 2 second to 0 5 nanosecond and triggering to 500 megahertz are pro vided The 7 92 is intended for use with high frequency 7000 Series Oscilloscope systems however mast 7 92 functions are compatible with all 7000 Series Oscilloscopes Other features include lighted pushbutton switches compatibility with indicator oscilloscopes having an alphanumeric read out system and 0 to 9 8 times continuous sweep delay A VARIABLE control allows continuously variable sweep rates be tween calibrated steps Also when operating in the AUTO MAIN TRIGGERING MODE a bright base line is displayed in the absence of a trigger signal 2 Fig 1 1 7 92 Dual Time Base Iv REV A NOV 1975 REJ Not recommended for SYNC mode Section 1 7B92A Operators SPECIFICATION This instrument will meet the electrical characteristics listed under Performance Requirement in Table 1 1 following com plete calibration The following electrical characteristics apply over an ambient temperature range of 0 C to 50 as otherwise indicated Warmup time for given accuracy is 20 minutes TABLE 1 1 Electrical Characteristics Supplemental Characteristic Performance Requirement
8. of ALT Sweep Display Sweep Rates Sweep Accuracy Over Center 8 Div 2 s Div to 20 ns Div 10 ns Div Over Any 2 Div Portion Within 8 Div REV A NOV 1975 TABLE 1 1 cont Electrical Characteristics Performance Requirement 0 2 s div to 0 5 ns div in 27 calibrated steps Specification 7B92A Operators Supplemental Information 50 Q within 7 0 1 p p using 1 GHz Reflectometer Selected by TIME DIV switch Steps in a 1 2 5 sequence Measured in 7900 Series Oscilloscope 15 C to 35 Within 296 0 C to 50 C Within 396 Within 396 Within 496 Within 496 Within 596 Within 5 Within 696 Within 5 Within 596 Within 1096 Within 10 Continuously variable between calibrated sweep rates 0 2 s div to 10 ns div in 23 calibrated steps Measured in 7900 Series Oscilloscope 15 C to 35 C Within 2 Within 3 Within 5 0 C to 50 C Within 3 Extends sweep rate to at least 0 5 5 VARIA BLE control internally switchable between De laying and Delayed Sweeps Selected by TIME DIV OR DLY TIME switch Steps in a 1 2 5 sequence Within 4 Within 5 1 3 Specification 7B92A Operators Characteristic INTENSIFIED SWEEP Delaying Sweep Trace of ALT Sweep Display cont Variable Sweep Rate Trace Separation Alt Off VARIABLE TIME DELAY Delay Time Range DLY TIME DIV Settings 2 s Div to 10 ns Div Differential Delay Time Measurement Accuracy 1
9. or sub harmonic of the triggering signal to pro vide a stable display RELEASE LATCH 1752 16 Fig 2 2 Location of release latch 2 2 9 SLOPE Switch Permits triggering on the positive or negative slope of the trigger signal except in HF SYNC TRIG D Indicator When lit indicates that the sweep is triggered and will produce a display with correct setting of the POSI TION control and the controls on the associated plifier plug in unit s and oscilloscope MODE Switches Select the desired main triggering mode Selected mode is indicated by lighted pushbutton AUTO Selects a triggered sweep initiated by the ap plied trigger signal at a point determined by the LE VEL control and SLOPE switch when the trigger sig nal repetition rate is above 30 hertz and within the frequency range selected by the COUPLING switches When the LEVEL control is outside the amplitude range the trigger repetition rate is outside the fre quency range selected by the COUPLING switches or the trigger signal is inadequate the sweep free runs to provide a reference trace HF SYNC Sweep initiated by trigger signals with re petition rates above 100 megahertz and within the range selected by the COUPLING switch Stable dis play can be obtained when the LEVEL control adjusts the frequency of the trigger generator to the frequency or subharmonic of the trigger signal When the LE VEL control is adjusted to fr
10. surement points is 5 divisions see Fig 2 7 and the TIME DIV OR DLY TIME switch is set to 1 ms Using the formula horizontal TIME DIV OR Time Duration distance X DLY TIME divisions setting Substituting the given values Time Duration 5x 0 1 millisecond 0 5 millisecond Determining Frequency The time measurement technique can also be used to deter mine the frequency of asignal The frequency of a period ically recurrent signal is the reciprocal of the time duration period of one complete cycle Use the following procedure 1 Measure the time duration of one complete cycle of the waveform as described in the previous application 2 Take the reciprocal of the time duration to determine the frequency Example The frequency of the signal shown in Fig 2 7 which has a time period of 0 5 millisecond is Frequency T Werty time period 0 5 millisecond 2 13 Operating Instructions B92A Operators Risetime Measurements Risetime measurements employ basically the same techniques as time duration measurements The main difference is the points between which the measurement is made The follow ing procedure gives the basic method of measuring risetime between the 10 and 90 points of the waveform Falltime can be measured in the same manner on the trailing edge of the waveform 1 Connect the signal to be displayed to the input of the Amplifier plug in unit 2 Set the Vertical and Horizo
11. 0 times the TIME DIV OR DL Y TIME setting Jitter specification does not apply to the first 2 of the maximum available delay time DELAY TIME MULT dial setting less than 0 20 REV B NOV 1975 TABLE 1 2 Environmental Refer to the Specification for the associated oscilloscope Specification 7B92A Operators TABLE 1 3 Physical Net Weight 3 062 Ibs 1 372 See Fig 1 2 Dimensional Drawing Dimensions OVERALL DIMENSIONS MEASURED AT MAXIMUM POINTS 8d NOTE DIMENSIONS ARE GIVEN WITH TOP FIGURE IN INCHES AND BOTTOM FIGURE IN CENTIMETERS 14 6 37 1 Fig 1 2 Dimensional drawing Section 2 7 92 Operators OPERATING INSTRUCTIONS The 7B92A Dual Time Base Plug In Unit operates with a Tektronix 7000 Series Oscilloscope and 7A Series Amplifier plug in unit to form a complete high frequency oscilloscope system This section describes the operation of the front panel con trols and connectors provides general operating information an Operating Check Out procedure and basic applications for this instrument NOTE The ALT OFF position which allows the Intensified mode of operation is applicable to instruments SN 060000 up INSTALLATION The 7B92A is designed to operate in the horizontal plug in compartment of the oscilloscope This instrument can also be installed in a vertical plug in compartment to provide a vertical sweep on the crt However when used in thi
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13. 5 C to 35 C 2 s Div to 1 us Div Both DELAY TIME MULT dial settings at 0 50 or greater One or Both DELAY TIME MULT dial settings less than 0 50 50 ns Div to 10 ns Div Both delay times equal to or greater than 25 ns One of both delay times less than 25 ns Delay Time Jitter 0 2 s Div to 50 us Div 20 us Div to 10 ns Div TABLE 1 1 cont Electrical Characteristics Performance Requirement Continuously variable between calibrated sweep rates Intensified sweep can be positioned at least 3 5 div above the delayed sweep Intensified sweep of the delaying sweep is dis played when the TIME DIV switch is pulled out and rotated clockwise and the TRACE SEP control is in ALT OFF position 9 8 times the DLY TIME switch setting 0 to 1 96 s Within 0 75 of measurement 0 25 of full scale Within 0 7596 of measurement 0 5 of full scale 5ns Within 1 0 of measurement 0 5 of full scale Within 1 0 of measurement 1 0 of full scale 5 ns 1 part or less in 50 000 of the maximum available delay time 10 times the TIME DIV OR DLY TIME switch setting 1 part or less in 50 000 of the maximum available delay time 10 times the TIME DIV OR DLY TIME switch setting 0 5 ns Supplemental information Extends sweep rate to at least 0 5 s Variable con trol internally switchable between Delaying and Delayed Sweeps Allow Intensified Mode of operation Full scale is 1
14. Fig 2 Area of graticule used for most accurate time measure ments Operating Instructions 7B92A Operators Calibrated sweep rates in the Normal sweep display mode are 0 2 s Div to 0 5 ns Div By using the VARIABLE con trol Time Div Variable Selector connector set for variable Delayed Sweep rates uncalibrated sweep rates to 0 5 s Div are available Triggering in the Normal sweep display mode is controlled by the MAIN TRIGGERING controls ALTERNATE SWEEP DISPLAY To select the Alternate display mode pull out the DLY D Time Division knob and rotate it to a desired sweep rate faster than the TIME DIV OR DLY TIME switch setting In this mode both an inten sified sweep and a delayed sweep are displayed see Fig 2 6 The intensified trace of the Alternate sweep display provides an intensified portion on the delaying sweep during the time the delayed sweep is running The amount of delay time be tween the start of the delaying sweep and the intensified portion is determined by the TIME DIV OR DLY TIME switch and the DELAY TIME MULT dial Triggering for the delaying sweep portion of the intensified trace is con trolled by the MAIN TRIGGERING controls triggering for the intensified portion and the delayed sweep trace 15 controlled by the Delayed Triggering controls The TRACE SEP control vertically positions the intensified trace up to 3 5 divisions above the delayed sweep trace The brightness of the intensified zone may be va
15. IME DIV OR DLY TIME switch to 1 ms and press in the DLY D Time Division knob Normal sweep mode Rotate the Main Triggering LEVEL control for a stable display 16 Check that a stable display can be obtained with the Main Triggering COUPLING switch set to AC AC HF REJ and DC for both the positive and negative positions of the SLOPE switch Main Triggering LEVEL control may be ad justed as necessary to obtain a stable display Remove all connections from the oscilloscope system 17 Connect a 0 4 volt 1 kilohertz signal from the oscillo scope Calibrator to the Amplifier plug in unit and to the MAIN TRIG IN connector Set the Main Triggering SOURCE switch to EXT Set the Amplifier plug in unit Volts Div switch for about 4 divisions of display Check that a stable REV A NOV 1975 display be obtained with the Main Triggering COUPLING switch set to AC AC HF REJ and DC for both the positive and negative positions of the SLOPE switch Main Triggering LEVEL control may be adjusted as necessary for a stable display 18 Change the Main Triggering SOURCE switch to EXT 10 Set the oscilloscope Calibrator for 4 volts at 1 kilo hertz and adjust the Amplifier plug in unit Volts Div switch for about 4 divisions of display Check that a stable display can be obtained with the Main Triggering COUPLING switch set to AC AC HF REJ DC for both the positive and negative positions of the SLOPE switch Main Triggering LEVEL c
16. Information MAIN TRIGGERING Trigger Sensitivity Triggering Frequency Minimum Triggering Range Signal Required Operating in AUTO NORM or SINGLE SWEEP MODE COUPLING AC 30 Hz to 20 MHz 0 5 100 20 MHz to 500 MHz 1 500 0 AC LF REJ 30 Hz to 20 MHz 0 5 100 20 MHz to 500 MHz 1 0 500 0 DC Dc to 20 MHz 0 5 100 20 MHz to 500 MHz 1 0 500 Operating in HF SYNC MODE AC 100 MHz to 500 MHz AC LF REJ DC Use NORM or SINGLE SWEEP MODE for signals below about 30 Hz External Trigger Input Level Range Not applicable in HF SYNC MAIN TRIGGERING Mode EXT At least and 3 5 volts EXT 10 At least and 35 volts Maximum Safe Input 1 5 Input 250 V dc peak ac 5022 Input 1 W average 7 V rms Will not trigger on the sine waves of 8 div amplitude or less internal or 3 V or less external at 60 Hz or below For Internal Triggering only the specified 3 dB frequency of the Vertical System replaces any frequencies in the above table when the num ber in the table is greater than the 3 dB frequency of the Vertical System 3 Triggering signal amplitude requirements increased by factor of 10 for EXT 10 operation REV A APR 1975 1 1 Specification 7B92A Operators Characteristic MAIN TRIGGERING cont Input R and C 1 Input 50 Q Input Resistance Reflection Coefficient Time Domain Trigger Jitter Internal or External DELAYED TRIGGERING Trigger Sensitivity COUP
17. LING AC DC Trigger Jitter Internal or External External Trigger Input Level Range EXT Maximum Safe Input 1 9 Input Q Input Input R and C 1 MQ Input specified 3 dB frequency of the Vertical System replaces any frequencies in the above table when the number in the table is greater than TABLE 1 1 cont Electrical Characteristics Performance Requirement 50 ps or less at 500 MHz Minimum Triggering Signal Required Triggering Frequency Range 30 Hz to 20 MHz 20 MHz to 500 MHz 100 1 0 500 Dc to 20 MHz 20 MHz to 500 MHz 50 ps or less at 500 MHz At least 3 5 V to 3 5 V the 3 dB frequency of the Vertical System 1 2 Supplemental Information Approximately 1 MQ paralleled by approxi mately 20 pF 50 within 7 0 1 p p using 1 GHz Re flectometer 250 V dc peak ac 1 W average 7 V rms Approximately 1 MQ paralleled by approxi mately 20 pF REV APR 1975 Characteristic DELAYED TRIGGERING cont Input R and C cont 50 Q Input Resistance Reflection Coefficient Time Domain NORMAL ALT Delayed Sweep Trace and DLY D SWEEP Sweep Rates Sweep Accuracy Over Center 8 Div 2 s Div to 20 ns Div 10 ns Div to 5 ns Div 2 ns Div to 1 ns Div 5 ns Div Over Any 2 Div Portion Within Center 8 Div 2 s Div to 10 ns Div 5 ns Div to 5 ns Div Variable Sweep Rate INTENSIFIED SWEEP Delaying Sweep Trace
18. The Main Triggering COUPLING switches select the method in which the trigger signal is connected to the trigger circuits lt Each position permits selection or rejection of some frequen cy components of the trigger signal which trigger the sweep REV A APR 1975 The AC pushbutton blocks the dc component of the trigger signal Signals with low frequency components be low about 30 hertz are attenuated In general ac coupling can be used for most applications However if the signal contains unwanted frequency components or if the sweep is to be triggered at a low repetition rate or dc level one of the other COUPLING switch positions will provide a better display AC LF REJ The AC LF REJ pushbutton rejects dc and attenuates low frequency trigger signals below about 30 kilohertz Therefore the sweep is triggered only by the higher frequency components of the trigger signal This position is particularly useful for providing stable triggering if the trigger signal contains line frequency components Also the AC LF REJ position provides the best alternate mode vertical displays at fast sweep rates when comparing two or more unrelated signals AC HF REJ The AC HF REJ pushbutton passes all low frequency signals between about 30 hertz and 50 kilohertz Dc is rejected and signals outside the above range are atten uated When triggering from complex waveforms this po sition is useful to provide a stable display of the low fr
19. e delaying sweep rate indicated by the TIME DIV OR DLY TIME switch gives the calibrated delay time before the start of the delayed sweep 2 12 DELAYED ae TRACE Fig 2 6 Typical alternate sweep display 1752 07 Delayed Sweep Triggering The Delayed Triggering LEVEL control determines the de layed triggering mode and delayed triggering level When the LEVEL control is in the RUNS AFTER DLY TIME detent position fully clockwise the delayed sweep starts immediately after the delay time determined by the TIME DIV OR DLY TIME switch and DELAY TIME MULT dial This mode permits selection of continuously variable delay times by rotating the DELAY TIME MULT dial The De layed Triggering LEVEL control and SLOPE COUPLING and SOURCE switches are inoperative When the delayed sweep is triggerable Delayed Triggering LEVEL out of the RUNS AFTER DELAY detent the delayed sweep does not start at the completion of the delay time Instead it waits until a trigger pulse is received by the Delayed Triggering circuits The delay time in this mode is dependent not only on the settings of the delay time controls but on the Delayed Triggering controls and the occurence of the delayed sweep triggering signal as well The primary purpose of this mode is to eliminate jitter from the delayed sweep waveform Since the delayed sweep is triggered by the input waveform jitter is eliminated from the delayed sweep display even though it may be inhe
20. e start of the intensified portion with the DE LAY TIME MULT dial to the part of the display to be mag nified Delayed Trigger LEVEL control must be in the RUNS AFTER DELAY TIME detent 7 Set the DLY D Time Division switch to a setting which intensifies the full portion of the display to be magnified The start of the intensified trace will remain as positioned in step 6 REV B NOV 1975 Operating Instructions 7B92A Operators ENKAN LA AA bes PAT NET LJ TL PLA SM A This portion of display cannot be viewed adequately because the main sweep is triggered on larger amplitude signals at the start of the display B Area of interest displayed by delaying the main sweep DLY D SWF mode _ 1752 12 Fig 2 11 Displaying complex signal using delayed sweep 8 Press in the DLY D Time Division switch for the Delayed Sweep mode 9 Slight re adjustment of the Main Triggering LEVEL con trol may be necessary to produce a stable display 10 Pulse jitter is shown by horizontal movement on the pulse take into account inherent jitter of the Delayed Sweep 11 Multiply the distance measured in step 10 by the DLY D Time Division switch setting to obtain pulse jitter in time 2 17 Operating Instructions 7B92A Operators 1752 13 Fig 2 12 Measuring pulse jitter 2 18 Example Assume that the horizontal movement is 0 6 divi sion see Fig 2 12 and the DLY D Time Division switch setti
21. ed if the LEVEL or POSITION control settings are changed 7 Rotate the DELAY TIME MULT dial to move the inten sified portion of the trace to the first pulse 8 Press in the DLY D Time Division switch for the DLY D SWP display mode 9 Adjust the DELAY TIME MULT dial to move the pulse or the rising portion to the center vertical graticule line Note the exact setting of the dial 16 Turn the DELAY TIME MULT dial clockwise until the second pulse is positioned to the same point as the first pulse If several pulses are displayed return to the ALT mode to locate the correct pulse Again note the exact dial setting 11 Subtract the first dial setting from the second and mul tiply by the delay time shown by the TIME DIV OR DLY TIME switch This figure is the time interval between pulses Example Assume the first dial setting is 2 60 and the se cond dial setting is 6 80 with the TIME DIV OR DL Y TIME switch set to 1 us see Fig 2 9 Time delay time Difference Second first TIME DIV Delayed dial dial x ORDLY Sweep setting setting TIME switch setting Substituting the given values Time Difference 6 80 2 60 x 1 millisecond 4 2 milliseconds Delayed Sweep Magnification The delayed sweep feature of the 7B92A provides apparent magnification of the displayed waveform The following me thod uses the RUNS AFTER DLY TIME mode to allow the delayed portion of the display to be positioned wi
22. ektronix Field Office or representative for assistance in making specific measurements Time Duration Measurements To measure the time between two points a waveform use the following procedure 1 Connect the signal to be displayed to the input of the Amplifier plug in unit 2 Set the Vertical and Horizontal Mode switches on the oscilloscope to display the plug in units used 3 Set the Volts Division switch of the Amplifier plug in unit to display about 4 divisions of waveform 4 Set the MAIN TRIGGERING controls to obtain a stable display 5 Set the TIME DIV OR DL Y TIME switch to the fastest sweep rate that displays less than 8 divisions between the time measurement points see Time Measurement discussion and Fig 2 7 6 Adjust the Amplifier plug in Position control to move the points between which the time measurement is made to the center horizontal graticule line 7 Adjust the horizontal POSITION control to position the time measurement points within the center 8 divisions of the graticule 8 Measure the horizontal distance between the time mea surement points Be sure the VARIABLE control is set to CAL REV A APR 1975 Operating Instructions 7B92A Operators 1752 08 Fig 2 7 Measuring the time duration between points on a wave form 9 Multiply the distance measured in step 8 by the setting of the TIME DIV OR DLY TIME switch Example Assume that the distance between the time mea
23. en changing indicator oscilloscopes DELAY TIME MULT Dial Provides variable delay of 0 to 9 8 times the basic de lay time selected by the TIME DIV OR DLY TIME switch Delayed Triggering Controls LEVEL Control Determines the delayed trigger mode and the delayed trigger level RUNS AFTER DELAY TIME LEVEL control turned fully clockwise into detent Delayed sweep runs im mediately following the delay time selected by the TIME DIV OR DLY TIME switch and the DELAY TIME MULT dial Delayed SLOPE COUPLING and SOURCE functions are inoperative Delayed Sweep Triggerable When the Delayed Trig gering LEVEL control is turned counter clockwise out of detent the delayed sweep is triggerable The Delayed Triggering LEVEL control can now be rota REV B NOV 1975 l LEVEL Control cont ted to select the amplitude point on the trigger signal at which the delayed sweep is triggered In the Delayed Sweep Triggerable mode the delayed SLOPE COUP LING and SOURCE functions are activated 17 SLOPE Switch Two position switch to select the slope of the trigger signal which starts the delayed sweep The delayed sweep can be triggered on the positive slope of the trigger signal The delayed sweep can be triggered on the nega tive slope of the trigger signal SOURCE Switch Two position pushbutton switch to select the source of the delayed trigger signal INT The delayed trigger signal is obtained fro
24. equen cy components AC HF REJ Coupling should not be used when operating in the HF SYNC triggering mode DC The DC pushbutton can be used to provide stable trig gering from low frequency signals which would be attenua ted in the other modes It can also be used to trigger the sweep when the trigger signal reaches a dc level set by the LEVEL control When using internal triggering the setting of the Amplifier plug in unit Position control affects the triggering point Main Trigger Source The Main Triggering SOURCE pushbutton switches select the source of the trigger signal which is connected to the main trigger circuits INT The INT pushbutton connects the trigger signal from the Amplifier plug in unit Further selection of the internal trigger signal may be provided by the Amplifier plug in unit or oscilloscope see the instruction manuals for these in struments for more information For most applications the internal source can be used However some applications require special triggering which cannot be obtained in the INT position In such cases the LINE or EXT positions of the SOURCE switches must be used LINE The LINE pushbutton connects a sample of the power line voltage from the oscilloscope to the trigger cir cuit Line triggering is useful when the input signal is time related multiple or submultiple to the line frequency It is also useful for providing a stable display of a line frequency Operating Instruc
25. equencies between sub harmonics the sweep free runs NORM Sweep initiated by the applied trigger signal at a point selected by the LEVEL control and SLOPE switch over the frequency range selected by the COU PLING switches Triggered sweep can be obtained only over the amplitude range of the applied trigger signal When the LEVEL control is either outside the amplitude range the trigger repetition rate 15 outside the frequency range selected by the COUPLING swit ches or the trigger signal is inadequate there is no trace SINGLE SWEEP RESET When the SINGLE SWEEP RESET pushbutton switch is pressed a single trace will be presented when the next trigger pulse is re ceived The SINGLE SWEEP RESET pushbutton re mains lit until a trigger is received and the sweep is completed The SINGLE SWEEP RESET pushbutton switch must be pressed again before another sweep can be displayed COUPLING Switches Select trigger signal coupling Selected coupling is in dicated by lighted pushbutton REV B NOV 1975 AC Rejects dc and attenuates ac signals below approxi mately 30 hertz Accepts signals between 30 hertz and 500 megahertz AC LF REJ Rejects dc and attenuates signals below 30 kilohertz Accepts signals between 30 kilohertz and 500 megahertz y AC HF REJ Rejects dc and attenuates signals above 50 kilohertz Accepts signals from 30 hertz to 50 ki lohertz DC Accepts all signals from dc to 500 megahertz
26. etermining Frequency Risetime Measurements Delayed Sweep Measurements Delayed Sweep Magnification Triggered Delayed Sweep Magnification Displaying Complex Signals Using Delayed Sweep Pulse Jitter Measurements OPTIONS 7B92A Operators PAGE 1 1 1 1 1 5 1 5 2 1 2 1 2 2 2 2 2 4 2 4 2 5 2 5 2 5 2 6 2 6 2 8 2 8 2 8 2 8 2 9 2 9 2 9 2 11 2 11 2 11 2 11 2 12 2 12 2 13 2 13 2 13 2 13 2 14 2 14 2 15 2 16 2 16 2 17 3 1 7B92A Operators FIGURE NO 1 1 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 2 9 2 10 2 11 2 12 LIST OF ILLUSTRATIONS 7B92A Dual Time Base Location of Variable and Mainframe Selector multi pin connectors Location of release latch Front panel controls and connectors Effect of LEVEL control and SLOPE switch on crt display Area of graticule used for most accurate time measurements Typical alternate sweep display Measuring the time duration between points on a waveform Measuring risetime Measuring time difference using delayed sweep Using delayed sweep for magnification Displaying a complex signal using delayed sweep Measuring pulse jitter PAGE 2 1 2 2 2 3 2 10 2 11 2 12 2 13 2 14 2 15 2 16 2 17 2 18 TABLE 1 1 1 2 1 3 2 1 LIST OF TABLES Electrical Characteristics Environmental Physical Risetime Measurements 7B92A Operators PAGE 1 1 1 5 2 14 7B92A Operators T VARIABLE CAL
27. fied The start of the intensified trace will remain as positioned 6 Measurement and magnification are as described in the in step 6 Delayed Sweep Magnification discussion 8 Press in the DLY D Time Division switch for the Delayed Sweep mode Displaying Complex Signals Using Delayed Sweep 9 Time measurements can be made from the display in the Complex signals often consist of a number of individual events conventional manner Sweep rate is set by the DLY D Time of differing amplitudes Since the trigger circuits are sensitive Division switch to changes in signal amplitude a stable display can normally be obtained only when the sweep is triggered by the event s 10 The apparent sweep magnification can be calculated by having the greatest amplitude However this may not produce dividing the TIME DIV OR DLY TIME switch setting by the the desired display of a lower amplitude portion which follows DLY D Time Division switch setting the triggering event The delayed sweep feature provides a means of delaying the start of the delayed sweep by a selected Example The apparent magnification of the display shown amount following the event which triggers the Main Sweep in Fig 2 10 with a TIME DIV OR DLY TIME setting of Generator Then the part of the waveform which contains the information of interest can be displayed at the delayed sweep rate 2 16 Use the following procedure 1 Set up the display as given in steps 1 t
28. ger output signal 50 ns and 1 V High Amplitude output 100 V 0502 01 Comparator output can be alter nately chopped to a reference voltage 190B Amplitude range 40 mV to 10 V p p 191 Frequency range 350 kHz to 100 MHz 0532 01 Frequency range 65 MHz to 500 MHz 180A Marker outputs 5 sec to 1 us Sinewave available at 20 10 and 2 ns Trigger pulses 1 10 100 Hz 1 10 and 100 kHz Multiple time marks can be generated simultaneously 181 Marker outputs 1 10 100 1000 and 10 000 plus 10 ns sinewave 184 Marker outputs 5 sec to 2 ns Sine wave available at 50 20 10 5 and 2 ns Separate trigger pulses of 1 and 1 sec 10 1 and 1 ms 10 and 1 us Marker amplifier pro vides positive or negative time marks of 25 V min Marker intervals of 1 and 1 sec 10 1 and 1 ms 10 and 1 ws 2901 Marker outputs 5 sec to 0 1 us Sinewave available to 50 10 and 5 ns Separate trigger pulses from 5 sec to 0 1 us Multiple time marks can be gene rated simultaneously NOTE All TM 500 generator outputs short proof All TM 500 plug in instruments require TM 500 Series Power Module REV A OCT 1975
29. he front panel of the oscilloscope Even though the gain of the oscilloscope is standardized the sweep calibration of the 7B92A should be checked when installed The procedure for checking the unit is given under Sweep Calibration in the Operating Checkout procedure in this section 1752 02 Fig 2 1 Location of Variable and Mainframe Selector multi pin connectors REV B NOV 1975 2 1 Operating Instructions 7B92A Operators To remove the 7B92A pull the release latch see Fig 2 2 to disengage the unit from the oscilloscope and pull it out of the plug in compartment FRONT PANEL CONTROLS CONNECTORS AND INDICATORS All controls connectors and indicators required for the operation of the 7B92A except the Time Div Variable and Mainframe Selectors are located on the front panel A brief description of the front panel controls connectors and indicators is given here More detailed information is given under General Operating Information Fig 2 1 shows the Time Div Variable and Mainframe Selectors Fig 2 3 shows the front panel controls connectors and indicators Main Triggering Controls LEVEL Control Selects amplitude point on trigger signal where sweep triggering occurs when the Main Triggering Mode AU TO NORM or SINGLE SWEEP switches are pressed When the Main Triggering Mode HF SYNC switch 15 pressed the LEVEL control adjusts the frequency of the trigger generator to synchronize with the frequen cy
30. hrough 8 under Delayed Sweep Magnification 2 Time measurements can be made from the display in the conventional manner Sweep rate is set by the DLY D Time Division switch Example Fig 2 11 shows a complex waveform as displayed on the crt The circled portion of the waveform cannot be viewed in any greater detail because the sweep is triggered by the larger amplitude pulses at the start of the disolay and a faster sweep rate moves this area of the waveform off the graticule The second waveform shows the area of interest magnified 4 times using the Delayed Sweep The DELAY TIME MULT dial has been adjusted so the delayed sweep starts just before the area of interest Pulse Jitter Measurements In some applications it is necessary to measure the amount of jitter on the leading edge of a pulse or jitter between pul ses See Fig 2 12 1 Connect the signal to be displayed to the Amplifier plug in unit Set the Vertical and Horizontal Mode switches on the oscilloscope to display the plug in units used 2 Set the Volts Division switch of the Amplifier plug in unit to produce about 4 divisions of display amplitude 3 Adjust the MAIN TRIGGERING controls for a stable display 4 Set the TIME DIV OR DL Y TIME switch to a sweep rate which displays the complete waveform 5 Pull out the DLY D Time Division switch for the Alter nate Display Mode Rotate the TRACE SEP control clock wise from the ALT OFF position 6 Position th
31. ibed may produce too much jitter at high apparent magnification The Delayed Sweep Triggerable mode provides a more stable display since the delayed sweep display is triggered at the same point each time 1 Set up the display as given in steps 1 through 7 in the Delayed Sweep Magnification procedure 2 Rotate the Delayed Triggering LEVEL control counter clockwise out of the RUNS AFTER DELAY TIME detent Select the desired Delayed Trigaering SLOPE COUPLING and SOURCE 3 Adjust the Delayed Triggering LEVEL control to produce an intensified portion on the display 4 Inability to produce an intensified zone on the display indicates that the Delayed Triggering controls are incorrect 1752 11 ly set If the condition cannot be remedied with the Delay ed Triggering controls by increasing the display amplitude lower volts division setting externally trigger the delayed a Fig 2 10 Using delayed sweep for magnification sweep 6 Position the start of the intensified portion with the DE 5 When the correct portion of the display is intensified LAY TIME MULT dial to the part of the display to be mag press in the DLY D Time Division switch for the Delayed nified Sweep mode slight readjustment of the Delayed Triggering LEVEL control may be necessary to produce a stable delay 7 Set the DLY D Time Division switch to a setting which ed sweep display intensifies the full portion of the display to be magni
32. igger output signal at least 1 V High Amplitude out put 60 V Does not have chopped feature Amplitude range 5 mV to 5 5 V p p Frequency range 250 kHz to 250 MHz Frequency range 250 kHz to 250 MHz Marker outputs 5 sec to 1 ns Sinewave available at 5 2 and 1 ns Trigger output slaved to marker output from 5 sec through 100 ns One time mark can be generated at a time TG 501 Marker outputs 5 sec to 1 ns Sine wave available at 5 2 and 1 ns TG 501 Marker outputs 5 sec to 1 ns Sine wave available at 5 2 and 1 ns Trigger output slaved to marker output from 5 sec through 100 ns One time mark can be generated at a time Marker outputs 5 sec to 1 ns Sine wave available at 5 2 and 1 ns Trigger output slaved to marker output from 5 sec through 100 ns One time mark can be generated at a time 107 Risetime less than 3 0 ns into 50 0 i 108 10 V output pulse 1 ns Risetime 111 Risetime 0 5 ns 30 to 250 ns Pretrigger Pulse delay 114 10 V output Short proof output 115 Paired Burst Gated and Delayed pulse mode 10 V output Short proof output 108 10 V output 111 Risetime 0 5 ns 30 to 250 ns Pretrigger pulse delay 114 10 V output Short proof output 115 Paired Burst Gated Delayed amp Un delayed pulse mode 10 V output Short proof output 2101 Paired and Delayed pulse 10 V output 106 Positive and Negative going trig
33. lay period as selec ted by the TIME DIV OR DL Y TIME switch and the DELAY TIME MULT dial setting 0 VARIABLE Two position switch actuated by the VARIABLE con trol to select calibrated or uncalibrated sweep rates In the CAL position knob in the VARIABLE con trol is inoperative and the sweep rate is calibrated When pressed and released the knob moves out to activate the VARIABLE control for uncalibrated sweep rates The sweep rate in each TIME DIV switch position can be reduced to at least the sweep rate of the next slower position The VARIABLE control will operate with either the delaying or delayed sweep by means of the internal Time Div Variable Selector POSITION Control Positions the display horizontally on the graticule CONTRAST Control Varies the relative brightness of the intensified portion of the delaying trace when in the Alternate mode TRACE SEP ALT OFF Control This control vertically positions the delaying sweep display up to 3 5 divisions above the delayed sweep display when in the Alternate mode The ALT OFF position allows the Intensified sweep mode of oper ation permitting the display of an intensified portion of the delaying sweep INTENSITY Control Varies the intensity of the Intensified sweep only when operating in the INTENS or ALT mode SWP CAL Adjustment Screwdriver adjustment sets the basic timing of the 7B92A to compensate for slight differences in input sensitivity wh
34. m the vertical amplifier of the oscilloscope EXT The delayed trigger signal is obtained from an external source connected to the DLY D TRIG IN connector COUPLING Switch Two position pushbutton switch to determine the method of coupling the trigger signal to the delayed trigger circuit AC Rejects and attenuates signals below 30 hertz Accepts trigger signals from 30 hertz to 500 mega hertz DC Accepts trigger signals from dc to 500 mega hertz Front Panel Inputs MAIN TRIG IN Connector Serves as an external trigger input for the main trigger ing circuit when the Main Triggering Source EXT or EXT 10 pushbutton switches are pressed 21 TERM Switch Two position pushbutton switch to select 50 ohms out position or 1 megohm position input impedance for the MAIN TRIG IN and DLY D TRIG IN connec tors REV B NOV 1975 Operating Instructions 7B92A Operators 22 DLY D TRIG IN Connector Serves as an external trigger input for the delayed trig gering circuit when the Delayed Triggering SOURCE switch is set to EXT CAUTION Do not exceed 7 volts rms of external signal when 50 termination is selected FAMILIARIZATION PROCEDURE The following procedure may be used for familiarization or as a check of basic instrument operation The procedure is divided into two parts Sweep Functions and Triggering Functions A complete operating check of the 7B92A func tions can be made by perfo
35. ng is 1 microsecond Using the formula horizontal DEY D Pulse Jitter jitter Time Division divisions setting Substituting the given values Pulse Jitter 0 6 x 1 microsecond 0 6 microsecond REV APR 1975 Section 3 7B92A Operators OPTIONS No Options available at the time of this printing Refer to the CHANGE INFORMATION in the back of this manual for Options available after this printing MANUAL CHANGE INFORMATION At Tektronix we continually strive to keep up with latest electronic developments by adding circuit and component improvements to our instruments as soon as they are developed and tested Sometimes due to printing and shipping requirements we can t get these changes immediately into printed manuals Hence your manual may contain new change information on following pages A single change may affect several sections Since the change information sheets are carried in the manual until all changes are permanently entered some duplication may occur If no such change pages appear following this page your manual is correct as printed SERVICE NOTE Because of the universal parts procurement problem some electrical parts in your instrument may be different from those described in the Replaceable Electrical Parts List The parts used will in no way alter or compromise the performance or reliability of this instrument They are installed when necessary to ensure prompt delivery to the cust
36. ntal Mode switches on the oscilloscope to display the plug in units used 3 Set the Volts Division switch and the Variable Volts Division control of the Amplifier plug in unit to produce a signal an exact number of divisions in amplitude 4 Center the display about the center horizontal graticule line with the Amplifier plug in unit Position control 5 Set the MAIN TRIGGERING controls to obtain a stable display 6 Set the TIME DIV OR DLY TIME switch to the fastest sweep rate that displays less than 8 divisions between the 1096 and 90 points on the waveform 7 Determine the 10 and 90 points on the rising portion of the waveform The figures given in Table 2 1 are for the points 1096 up from the start of the rising portion and 1096 down from the top of the rising portion 9095 point TABLE 2 1 Risetime Measurements Divisions Vertical 10 and 90 vertically display points between divisions divisions 10 and 90 points 4 0 4 3 6 3 2 5 0 5 4 5 4 0 6 0 6 and 5 4 4 8 7 0 7 and 6 3 5 6 8 0 8 and 7 2 6 4 8 Measure the horizontal distance between the 10 and 9095 points Be sure the VARIABLE control is set to CAL 9 Multiply the distance measured in step 8 by the setting of the TIME DIV OR DLY TIME switch 2 14 Example Assume that the horizontal distance between the 1096 and 9096 points is 4 divisions see Fig 2 8 and the TIME DIV OR DLY TIME switch is set to 20 ns Applying the time dura
37. omer Order replacement parts from the Replaceable Electrical Parts List E 43 CALIBRATION TEST EQUIPMENT REPLACEMENT Calibration Test Equipment Chart This chart compares TM 500 product performance to that of older Tektronix equipment Only those characteristics where significant specification differences occur are listed In some cases the new instrument may not be a total functional replacement Additional support instrumentation may be needed or a change in calibration procedure may be necessary DM 501 replaces 7D13 PG 501 replaces 107 108 111 114 115 PG 502 replaces 107 108 111 114 115 2101 PG 506 replaces 106 067 0502 01 SG 503 replaces 190 190A 190B 191 067 0532 01 TG 501 replaces 180 180A 181 184 2901 Comparison of Main Characteristics PG 501 Risetime less than 3 5 ns into 50 0 PG 501 5 V output pulse 3 5 ns Risetime PG 501 Risetime less than 3 5 ns 8 ns Pretrigger pulse delay PG 501 5 V output PG 501 Does not have Paired Burst Gated or Delayed pulse mode 5 V dc Offset Has 5 V output PG 502 5 V output PG 502 Risetime less than 1 ns 10 ns Pretrigger pulse delay PG 502 5 V output PG 502 Does not have Paired Burst Gated Delayed amp Undelayed pulse mode Has 5 V output PG 502 Does not have Paired or Delayed pulse Has 5 V output Positive going tr
38. ontrol may be adjusted as necessary to obtain a stable display Remove all connections from the oscillo scope system 19 Set the Main Triggering COUPLING switch to AC and SOURCE switch to INT Connect 1 kilohertz Calibrator signal from the oscilloscope to the Amplifier plug in unit Input and adjust for about 4 divisions of display amplitude Adjust the Main Triggering LEVEL control for a stable dis play Set the MODE switch to NORM and check for a sta ble display Change the MODE switch to AUTO and adjust the LEVEL control for a free running display Change the MODE switch to NORM and check for no display 20 Adjust the Main Triggering LEVEL control for a stable display Change the Main Triggering MODE switch to SIN GLE SWEEP Press the RESET button and check for one sweep as the RESET button is pressed Remove the 1 kilo hertz signal from the Amplifier plug in unit and press the RESET button Check for no display and READY light on Connect the 1 kilohertz signal to the Amplifier plug in unit Input and check for one sweep as the signal is applied Remove all connections from the oscilloscope system 21 Set the Main Triggering MODE switch to AUTO and SOURCE switch to AC Turn the Delayed Triggering LE VEL control fully clockwise to the RUNS AFTER DLY TIME position Pull out the DLY D Time Division switch and rotate to 0 2 ms Alternate mode Connect a 0 4 volt 1 kilohertz signal from the oscilloscope Calibrator to the Am
39. ovides a triggered display with the correct setting of the LEVEL control see Trigger Level discussion whenever an adequate trigger signal is ap plied The TRIG D indicator lights when the display is trig gered When the trigger repetition rate is outside the frequency range selected by the COUPLING switch or the trigger signal is inadequate the sweep free runs at the sweep rate indicated by the TIME DIV OR DLY TIME switch TRIG D indicator off An adequate trigger signal ends the free running condi tion and a triggered display is presented When the LEVEL control is at a setting outside the amplitude range of the trig ger signal the sweep also free runs at the sweep rate indica ted by the TIME DIV OR DL Y TIME switch This type of free running display can be useful when it is desired to mea sure only the maximum peak to peak amplitude of a signal without observing the waveshape such as in bandwidth measurements HF SYNC The HF SYNC pushbutton permits stable dis plays of repetitive signals with only 0 5 division of internal trigger signal 100 millivolts external signal required for frequencies between 100 megahertz and 500 megahertz A triggered display is obtained when the LEVEL control ad justs the frequency of the trigger generator to the frequency or subharmonic of the trigger signal Stable displays may be obtained several times between the limits of the LEVEL con trol depending on the amplitude and frequency of the trig
40. play HIGH FREQUENCY SYNCHRONIZATION Perform the following procedure to obtain a triggered alternate normal or delayed sweep with a 100 megahertz to 500 megahertz input signal NOTE To check HF SYNC operation a signal source frequen cy between 100 megahertz and 500 megahertz is quired If a 100 to 500 megahertz signal source is not desired to check the HF SYNC operation the last two steps of this procedure may be deleted 25 Change the Main Triggering MODE switch to HF SYNC Connect a high frequency signal source 100 to 500 mega hertz to the Amplifier plug in unit Input and adjust for 4 divisions of vertical deflection Adjust the TIME DIV OR DLY TIME switch and DLY D Time Division switch for about 6 cycles of display Rotate the Main Triggering LE VEL control throughout its range and note that the sweep is alternately stable then free running several times during the rotation stable display indicates that the trigger genera tor frequency is adjusted to a subharmonic of the trigger signal frequency Check that stable displays can also be obtained with the Main Triggering COUPLING switch set to AC AC LF REJ and DC Main Triggering LEVEL con trol may be adjusted as necessary for a stable display 26 Pull out the DLY D Time Division switch rotate it to the next fastest sweep rate from the setting of the TIME DIV OR DLY TIME switch Alternate mode When the LEVEL control is in the detent RUNS AFTER DELAY TIME
41. plifier plug in unit Input and adjust for about 2 divisions of display amplitude Rotate the Main Triggering LEVEL control for a stable intensified display The INTENSITY control may need to be adjusted to view the intensified dis play Rotate the DELAY TIME MULT dial and note that the delay time before the intensified portion of display 15 continuously variable 22 Set the Delayed Triggering SLOPE COUPLING and SOURCE switches to AC and INT Rotate the Delay ed Triggering LEVEL control counterclockwise out of the detent and adjust for a stable display Rotate the DELAY TIME MULT dial and note that the intensified sweep does not start at the completion of the delay time but waits for the next trigger pulse REV A NOV 1975 Operating Instructions 7B92A Operators 23 Check that a stable display can be obtained with the Delayed Triggering COUPLING switch set to AC and DC for both the and positions of the SLOPE switch Delayed Triggering LEVEL control may be adjusted as necessary for a stable display 24 Change the Delayed Triggering SOURCE switch to EXT Connect a 0 4 volt 1 kilohertz signal from the oscil loscope Calibrator to the DLY D TRIG IN connector Check that a stable display can be obtained with the Delayed Trig gering COUPLING switch set to AC and DC for both the and positions of the SLOPE switch Delayed Trig gering LEVEL control may be adjusted as necessary for a stable delayed sweep dis
42. rent in the input waveform When jitter in the delayed sweep display is not a problem the RUNS AFTER DLY TIME mode should be used In the Delayed Sweep Triggerable mode the Delayed Trig gering LEVEL control is rotated to select the amplitude point on the trigger signal at which the delayed sweep is triggered The SLOPE COUPLING and SOURCE func tions are the same for delayed triggering as for MAIN TRIG GERING see Main Triggering SLOPE COUPLING SOURCE and TERM switch discussions in this section REV A NOV 1975 Mainframe Operating Modes The 7B92A may be operated in a 7000 Series Oscilloscope with two horizontal compartments as an independent time base or as a delayed sweep unit in the RUNS AFTER DE LAY TIME or Triggerable After Delay Time modes The instrument can be operated independently in either Hori zontal plug in compartment or as a Delayed Sweep plug in unit in the B Horizontal compartment Refer to the appro priate oscilloscope manual for additional mainframe hori zontal operating information APPLICATIONS The following information describes the procedures and tech niques for making basic measurements with a 7B92A install ed a 7000 Series Oscilloscope These applications are not described in detail since each application must be adapted to the requirements of the individual measurement This in strument can also be used for many applications not des cribed in this manual Contact your local T
43. ried by the CON TRAST control The brightness of the intensified sweep may be varied by the 7 92 INTENSITY control INTENSIFIED SWEEP MODE The intensified sweep mode Intens is selected when the DLY D Time Division switch is pulled out rotated to the desired sweep rate faster than the TIME DIV or DLY TIME switch setting and the TRACE SEP control is rotated counterclockwise to the ALT OFF position DELAYED SWEEP DISPLAY The Delayed sweep display mode is selected when the DLY D Time Division switch is pulled out rotated to the desired sweep rate and then push ed in In this mode only the delayed sweep is displayed Calibrated sweep rates in the Delayed sweep mode are avail able from 0 2 s Div to 0 5 ns Div By using the VARIABLE control Time Div Variable Selector connector set for varia ble delayed sweep rates uncalibrated delayed sweep rates to 0 5 s Div are available Triggering for the delayed sweep is controlled by the Delayed Triggering controls Delay Time Multiplier The DELAY TIME MULT dial functional in the Delayed Alternate or Mainframe Delaying modes provides 0 to 9 8 times continuous sweep delay The amount of time that the delaying sweep runs before the start of the delayed sweep is determined by the settings of the TIME DIV OR DLY TIME switch and the DELAY TIME MULT dial For example a DELAY TIME MULT dial setting of 3 55 corresponds to 3 55 crt divisions of delaying sweep Thus 3 55 multiplied by th
44. rming both parts or each part may be performed separately If performing the Familiari zation Procedure reveals a malfunction or improper calibra tion first check the operation of the associated plug in units then refer to the 7B92A Service manual NOTE For optimum high frequency performance the 7B92A should be installed in an oscilloscope system with simi lar frequency and sweep rate capabilities Setup Procedure 1 Install the 7B92A a horizontal compartment of the oscilloscope 2 Install the Amplifier plug in unit in a vertical compart ment 3 Turn on the oscilloscope and allow at least 20 minutes warmup 4 Set the 7B92A controls as follows Main Triggering SLOPE MODE AUTO COUPLING AC SOURCE INT Delayed Triggering RUNS AFTER DELAY TIME LEVEL 2 5 Operating Instructions 7B92A Operators Delayed Triggering cont SLOPE COUPLING AC SOURCE INT Sweep Controls POSITION Midrange INTENSITY As desired TIME DIV OR 1 ms DLY TIME DLY D Time Division 1 ms knob in VARIBLE CAL Time Div Variable Selector Internal DELAY TIME MULT 1 00 TRACE SEP Delayed Sweep Midrange Set the oscilloscope to display the plug in units and ad just for a well defined display See oscilloscope and Amplifier plug in unit instruction manuals for detailed operatinc instruc tions Sweep Functions NORMAL SWEEP Perform the following procedure to ob tain a normal sweep and demons
45. s man ner there are no internal triggering or retrace blanking pro visions and the unit may not meet the specifications given in Section 1 Before proceeding with installation check the settings of the Time Div Variable Selector multi pin connector and the Mainframe Selector multi pin connector see Fig 2 1 The Time Div Variable Selector determines whether the front panel Time Div VARIABLE control operates in con junction with the delaying or delayed sweeps The Main frame Selector adapts the 7B92A to the oscilloscope main frame being used The two mainframe selections are 1 7800 and 7900 Series Oscilloscopes 2 All other 7000 Series Oscilloscopes 7800 MAINFRAME 7800 PB34 SELECTOR OTHER a P535 7000 DELAYED TIME DIV P760 VARIABLE SELECTOR amp mmmmm P761 DELAYING NOTE The 7871 will not delay the 7B92A for displaying alternating Delaying and Delayed sweeps Instead it causes a sweep lock up to occur under the follow ing conditions with the 7B71 in the A Horizontal compartment and the 7B92A in the B Horizontal compartment the sweep locks up if the 7B92A is in its Alternate mode and the Mainframe Horizontal Mode is Alt Lock up can be avoided by changing the Mainframe Horizontal Mode to Chop or B This allows both 7B92A sweeps to be displayed To install the 7B92A in a plug in compartment push it in until it fits firmly into the compartment The front panel of the 7B924A should be flush with t
46. th the DELAY TIME MULT dial If there is too much jitter in the delayed sweep display use the Triggered Delayed Sweep Magnification procedure which follows this procedure REV A NOV 1875 Operating Instructions 7B92A Operators DELAY TIME MULT DIAL 6 80 DELAY TIME MULT DIAL TIME DIFFERENCE Fig 2 9 Measuring time difference using delayed sweep 1 Connect the signal to be displayed to the Amplifier plug in unit Set the Vertical and Horizontal Mode switches on the oscilloscope to display the plug in units used 2 Set the Volts Division switch of the Amplifier plug in unit to produce about 4 divisions of display amplitude 3 Adjust the MAIN TRIGGERING controls for a stable display 4 Set the TIME DIV OR DLY TIME switch to a sweep rate which displays the complete waveform see Fig 2 10 Pull out the DLY D Time Division switch for the Alter nate display mode Turn the Delayed Triggering LEVEL control clockwise into the RUNS AFTER DLY TIME de tent Rotate the TRACE SEP control clockwise from the ALT OFF position 2 15 Operating Instructions 7B92A Operators 200 ns and a DLY D Time Division switch setting of 20 ns is Apparent TIME DIV OR DLY TIME setting Magnification DLY D Time Division setting Substituting the given values Apparent 200 nanoseconds _ Magnification 20 nanoseconds 10 Triggered Delayed Sweep Magnification The delayed sweep magnification method just descr
47. the other MAIN TRIGGERING controls press the SINGLE SWEEP RESET pushbutton A single trace is presented each time the pushbutton is pressed Fur ther sweeps cannot be presented until the SINGLE SWEEP RESET pushbutton is pressed again If the displayed signal is a complex waveform composed of pulses of varying am plitude successive single sweep displays may not start at the same point on the waveform To avoid confusion due to the crt persistence allow the display to disappear before pressing the SINGLE SWEEP RESET pushbutton again At fast sweep rates it may be difficult to view the single sweep display The apparent trace intensity can be increased by reducing the ambient light level or using a viewing hood as recommended in the oscilloscope instruction manual When using the single sweep mode to photograph waveforms the graticule must be photographed separately in the normal manner to prevent over exposing the film Be sure the came ra system is well protected against stray light or operate the system in a darkened room For repetitive waveforms press the SINGLE SWEEP RESET pushbutton only once for each waveform unless the signal is completely symmetrical Ot herwise multiple waveforms may appear on the film For random signals the lens can be left open until the signal triggers the unit Further information on photographic tech niques is given in the appropriate camera instruction manual Main Trigger Coupling
48. tion formula to risetime Time horizontal TIME DIV OR Duration distance DLY TIME Risetime divisions setting Substitute the given values Risetime 4 x 20 nanoseconds 80 nanoseconds HORIZONTAL DISTANCE 1752 09 Fig 2 8 Measuring risetime Delayed Sweep Measurements The delayed sweep mode can be used to make accurate time measurements The following measurement determines the time difference between two pulses displayed on the same trace This application may also be used to measure time difference from two different sources dual trace or to measure time duration of a single pulse 1 Connect the signal to be displayed to the Amplifier plug in unit 2 Set the Vertical and Horizontal Mode switches on the oscilloscope to display the plug in units used 3 Set the Volts Division switch of the Amplifier plug in unit to produce a display about 4 divisions in amplitude 4 Adjust the MAIN TRIGGERING controls for a stable display 5 If possible set the TIME DIV OR DLY TIME switch to a sweep rate which displays about amp divisions between pulses 6 Set the DLY D Time Division switch to a setting 1 100 of the TIME DIV or DLY TIME switch setting and pull out the DLY D Time Division switch for the Alternate display mode Rotate the TRACE SEP control clockwise from the ALT OFF position This produces an intensified portion approximately 0 1 division in length NOTE Measurement accuracy will be affect
49. tions 7B92A Operators component in a complex waveform Line triggering cannot be used when operating in the HF SYNC triggering mode EXT The EXT pushbutton connects the signal from the MAIN TRIG IN connector to the trigger circuit The exter nal signal must be time related to the displayed waveform for a stable display An external trigger signal can be used to provide a triggered display when the internal signal is too low in amplitude for correct triggering or contains signal components on which triggering is not desired It is also useful when signal tracing in amplifiers phase shift networks wave shaping circuits etc The signal from a single point in the circuit can be connected to the MAIN TRIG IN connec tor through a probe or cable The sweep is then triggered by the same signal at all times and allows amplitude time rela tionship or waveshape changes of signals at various points in the circuit to be examined without resetting the MAIN TRIGGERING controls EXT 10 The EXT 10 pushbutton operates the same as described for EXT except that the external signal is attenua ted Attenuation of high amplitude external trigger signals is desirable to increase the effective range of the LEVEL control Input Impedance The input impedance of the MAIN TRIG IN and DLY D TRIG IN connectors may be selected by the front panel TERM switch IN 1MX2 The 1 MQ position is suitable for most low and medium frequency applications or
50. tors VARIABLE control is activated for uncalibrated sweep rates The sweep rate can be returned to the calibrated position by pressing the VARIABLE knob in This feature is useful when a specific uncalibrated sweep rate has been obtained and it is desired to switch between calibrated and uncalibrated sweep rates Switching from uncalibrated to calibrated and vice versa does not affect the setting of the VARIABLE control The VARIABLE control allows the sweep rate in each Time Division switch position to be de creased to at least the next adjacent switch position Time Measurement When making time measurements from the graticule the area between the second and tenth vertical lines of the gra ticule provides the most linear time measurements see Fig 2 5 Position the start of the timing area to the second vertical line and adjust the TIME DIV OR DLY TIME switch so the end of the timing area falls between the fourth and tenth vertical lines Display Modes Four display modes can be selected by appropriate settings of the TIME DIV OR DLY TIME and DLY D Time Division switches NORMAL SWEEP OPERATION To select the Normal sweep display mode press in the DLY D Time Division switch and set it to the same sweep rate as the TIME DIV OR DLY TIME switch Rotate the Delayed Triggering LE VEL control clockwise into the RUNS AFTER DELAY TIME position SECOND VERTICAL TENTH VERTICAL LINE H TIME MEASUREMENT e AREA 1752 06
51. trate the function of the related sweep controls 1 Perform the Setup Procedure 2 Connect a 4 volt 1 kilohertz signal from the oscilloscope Calibrator to the Amplifier plug in unit Input 3 Adjust the Amplifier plug in unit Volts Division switch for two divisions of display 4 Rotate the Main Triggering LEVEL control for a stable display 5 Rotate the POSITION control and note that the trace moves horizontally 6 Check the crt display for one complete cycle per division If necessary adjust the SWP CAL screwdriver adjustment for one complete cycle per division over the center 8 graticule divisions Be sure that the timing of the Calibrator signal is accurate within 0 596 ALTERNATE AND DELAYED SWEEP Perform the fol lowing procedure to obtain alternate delayed sweeps and demonstrate the function of the related sweep controls 7 Pull out the DLY D Time Division knob and rotate clock wise to 0 1 ms for the Alternate sweep mode Note both an intensified trace and a normal intensity delayed sweep trace on the crt Increased oscilloscope intensity may be required for viewing the delayed sweep 2 6 8 Rotate the INTENSITY control and note that it varies the intensity of the delaying sweep 9 Rotate the CONTRAST adjustment for adequate identi fication of the intensified portion of the delaying sweep when alternating with delayed sweep NOTE When operating in the Intensified Mode the intensi fied zone is con
52. trolled by the intensity of the test oscilloscope instead of the 7B92A Contrast and Intensity controls 10 Rotate the TRACE SEP control to vertically position the delaying sweep trace with respect to the delayed sweep trace With the TRACE SEP control in the ALT OFF posi tion only the Intensified sweep will be displayed 11 Rotate the DELAY TIME MULT dial and note that the amount of delay time before the intensified portion of the display is controlled by the DELAY TIME MULT dial 12 Press the DLY D Time Division switch in for the Delay ed sweep mode Note the delayed display with sweep rate determined by the DLY D Time Division switch 13 Press and release the VARIABLE control Rotate the VARIABLE control and note that the sweep rate indicated by the DLY D Time Division switch can be varied to at least the sweep rate of the next adjacent position 0 2 ms The internal Time Div Variable Selector must be set to Delayed Sweep position Return the VARIABLE control to the CAL position knob in Triggering Functions MAIN AND DELAYED TRIGGERING Perform the fol lowing procedure to obtain a triggered alternate normal or delayed sweep and demonstrate the function of the re lated controls 14 Perform the Set Up Procedure Connect the 1 kilohertz Calibrator signal from the oscilloscope to the Amplifier plug in unit Input and adjust for about 4 divisions of vertical dis play 15 Set the DLY D Time Division switch and the T
53. ts calibrated sweep rates for the delayed sweep The sweep rate for the delaying sweep is bracketed by the black lines on the clear plastic flange of the TIME DIV OR DLY TIME switch Sweep rate of the delayed sweep is indicated by the white line on the DLY D Division knob When the white line on the outer knob is set to the same position as the lines on the inner knob the two knobs lock together and the sweep rate of both genera tors is changed at the same time However when the DLY D Time Division knob is pulled outward the clear plastic flange is disengaged and only the delayed sweep rate is changed This allows changing the delayed sweep rate without chang ing the delaying sweep rate The TIME DIV OR DLY TIME switch and the DLY D Time Division switch also select dis play modes See Display Mode discussion in this section for further information A VARIABLE control is provided concentric with the TIME DIV OR DLY TIME and DLY D Time Division switches see Fig 2 3 This control can be used with either the delaying or delayed sweeps as determined by the Time Div Variable Selector multi pin connector internal see Fig 2 1 for loca tion The VARIABLE control also incorporates a two posi tion switch to determine if the applicable sweep is calibrated or uncalibrated When the VARIABLE control is pressed in it is inoperative However when pressed and released the REV A APR 1975 Operating Instructions 7B92A Opera
54. weep rate Four display modes can be selected by the following switch settings Normal Sweep A normal sweep is selected when the TIME DIV OR DLY TIME switch and the DL Y D Time Division switches are locked together at the same sweep rate The DLY D Time Division knob must be pressed in for normal sweep mode Calibrated sweep rates from 0 2 second division to 0 5 nanosecond divi sion can be selected ALT Sweep The Alternate mode is selected when the DLY D Time Division switch is pulled out and rotated clockwise and the TRACE SEP control is turned clock wise from the ALT OFF position In this mode the delaying sweep is displayed with an intensified zone during the time that the delayed sweep runs alternat ely with the delayed sweep Intensified Sweep The intensified sweep mode Intens is selected when the DLY D Time Division switch is pulled out and rotated to the desired sweep rate faster than the TIME DIV or DLY TIME switch setting and the TRACE SEP control is rotated counterclockwise to the ALT OFF position see Fig 2 3 In this mode a portion of the delaying sweep is intensified during the time that the delayed sweep generator runs DLY D Sweep The delayed sweep mode is selected when the DLY D Time Division switch is pulled out rotated for the desired delayed sweep rate and then pushed in this mode the delayed sweep is dis played at a rate determined by the DLY D Time Div ision switch at the end of each de
55. when using a 10X probe The 1 position provide a high input impedance for minimum loading on the trigger signal source OUT 50 The 5022 position is recommended for high frequency applications requiring maximum overall band width The ohm termination should be used when ex ternally triggering from a 50 ohm system Trigger Slope The Main Triggering SLOPE switch concentric with the Main Triggering LEVEL control determines whether the trigger circuit responds on the positive going or negative going portion of the trigger signal The trigger slope cannot be selected when operating in the high frequency synchroni zation mode When the SLOPE switch is in the positive going position the display start on the positive going por tion of the waveform in the negative going position the display starts on the negative going portion of the wave form see Fig 2 4 When several cycles of a signal appear in the display the setting of the SLOPE switch is often un important However if only a certain portion of a cycle is 2 9 Operating Instructions 7B92A Operators 2 10 CRT DISPLAY OBTAINED WITH SLOPE SWITCH SET TO POSITIVE POSITIVE SLOPE VA EE dE POSITIVE m SLOPE CRT DISPLAY OBTAINED WITH SLOPE SWITCH SET TO NEGATIVE Fig 24 NEGATIVE SLOPE NEGATIVE SLOPE

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