Tektronix 7B15 User's Manual
Contents
1. TESTE 2S ND ACE CRT DISPLAY OBTAINED WITH SLOPE SWITCH SET TO NEGATIVE UW ALATA AN TVA AIN ACI H MAV VEE Vv vi E NEN C1958 7 Figure 2 2 Effects of LEVEL control and SLOPE switch on crt display 2 7 Operating Instructions 7B15 TRIGGER LEVEL The TRIGGERING LEVEL control determines the voltage level on the trigger signal at which the sweep is triggered When the LEVEL control is set in the region the trigger circuit responds at a more positive point on the trigger signal When the LEVEL control is set in the region the trigger circuit responds at a more negative point on the trigger signal Figure 2 2 illustrates this effect with different settings of the SLOPE switch To set the LEVEL control first set the TRIGGERING MODE COUPLING SOURCE and slope Then set the LEVEL control fully counterclockwise and rotate it clockwise until the display starts at the desired point Less selection of the triggering level is available as the trigger signal frequency exceeds 150 megahertz In the HF SYNC mode the trigger LEVEL control varies the sensitivity of the trigger generator The LEVEL control is set to provide a stable display HORIZONTAL SWEEP RATES The TIME DIV switch provides calibrated sweep rates from 0 2 seconds division to 2 nanoseconds division in a 1 2 5 sequence The VARIABLE TIME DIV control must be in the cali2. OUT 890 IWATE MAX EXT TRIG IN A TIME FRACE SEP SWP Tektronix CAL 7815 DELAYING TIME BASE Q Figure 2 1 Front panel controls connectors and indicators 2 2 i 000000 0000000 9 9 00 Operating Instructions 7B15 TRIGGERING LEVEL Control Selects a point on the trigger signal where triggering occurs SLOPE Switch Permits sweep to be triggered on negative or positive going portions of the trigger signal READY indicator ilturninates when sweep circuit is armed SINGLE SWP MODE TRIG D indicator Nluminates when the display is triggered MODE Pushbuttons Selects the operating mode of the triggering circuits COUPLING Pushbuttons Selects the method of coupling the trigger signal to triggering circuit SOURCE Pushbuttons Selects source of the trigger signat SWEEP POSITION Control Provides horizontal positioning FINE Controi Provides precise horizontal positioning HOLD OFF Controi Permits hold off period to be varied to improve triggering stability of repetitive complex waveforms MAG Pushbutton Selects X10 magnified or unmagnified sweep TIME DIV Switch Selects the sweep rate of the sweep generator VARIABLE Control and CAL Switch Selects calibrated or uncalibrated sweep rates Uncalibrated sweep rates be continuously reduced to at least the sweep rate of the next slower position SWP CAL Adjustment Compensates for basic tim
3. TIME MEASUREMENT AREA C1752 06 Figure 2 3 Area of graticule used for most accurate time measurements form see Fig 2 4 The equivalent length of the magnified sweep is more than 100 divisions any 10 division portion can be viewed by adjusting the POSITION and FINE POSITION controls to bring the desired portion into the viewing area When the MAG switch is set to X10 OUT the equivalent magnified sweep rate can be determined by dividing the TIME DIV setting by 10 the equivalent magnified sweep rate is displayed on the crt readout VARIABLE HOLD OFF The HOLD OFF control improves triggering stability on repetitive complex waveforms by effectively changing the repetition rate of the horizontal sweep signal The HOLD OFF control should normally be set to its minimum setting When a stable display cannot be obtained with the TRIGGERING LEVEL control the HOLD OFF control can be varied for an improved display a stable display cannot be obtained at any setting of the LEVEL and HOLD OFF controls check the TRIGGERING COUPLING and SOURCE switch settings DELAY TIME OPERATION A 7B15 installed in the mainframe horizontal compartment can delay a companion time base unit installed in the horizontal compartment When operating the 7B15 in a delaying mode B DELAY MODE switch set to B STARTS AFTER DLY or B TRIGGERABLE AFTER DLY an intensified zone is provided on the delaying sweep display during the time that
4. MEASURED FROM 90 TO lt PUSH FALL TIME A 1 000 us PULSE WIDTH 04 00 us PULSE WIDTH A 1960 35 Figure 2 8 Measuring risetime fall time period frequency or pulse width the A differential time mode 2 13 Operating Instructions 7B15 DELAYED SWEEP MAGNIFICATION By selecting the mainframe alternate or chopped horizontal mode a dual trace display of both the delaying sweep and the delayed sweep can be obtained In the delay time mode i e TRACE SEP control in the OFF position the delayed B sweep appears as a magnified display of the single intensified portion on the delaying sweep trace In the delta differential time mode i e TRACE SEP control rotated counterclockwise out of the OFF position the delayed B sweep appears as a dual magnified display of both intensified portions of the delaying A sweep trace The dual delayed B sweep displays can be superimposed or separated by rotating the TRACE SEP control The following procedures use alternate or chopped horizontal dual trace operation to Magnify a selected segment of the delaying A sweep and determine apparent magnification in the delay time mode 2 make more accurate time interval measurements in the delay time and A differential time modes and 3 examine an event that occurs within a selected time interval after a known delay time in the delay ti
5. COUPLING visa casis do ek a grag eda ee eis AC SOURCE oy DELAY INDEPENDENT ees OFF fully clockwise POSITION EX RECTE RAN ERA na Midrange TIMEZDIV aco annie cun ous 1 ms VARIABLE CAL IN Calibrated Pushed in HOLD OFF MIN fully counterclockwise MAG riv e EA X1 pushed in EXT TRIG OUT 500 4 Turn on the oscilloscope and allow at least 20 minutes warmup 5 Set the mainframe vertical and horizontal modes to display the plug in units used and adjust the intensity and focus for a well defined display See the oscilloscope mainframe and amplifier unit instruction manuals for detailed operating instructions SWEEP FUNCTIONS Normal Sweep Perform the following procedure to obtain a normal sweep and to demonstrate the function of the related controls 1 Perform the preceding Setup Procedure 2 Connect 0 4 volt 1 kilohertz signal from the mainframe calibrator to the amplifier plug in unit input 3 Set the amplifier plug in unit deflection factor for 4 divisions of display 4 Adjust the LEVEL control for a stable display 5 Turn the POSITION control and note that the trace moves horizontally 6 Turn the FINE control and note that the display can be precisely positioned horizontally 7 Check the display for one complete cycle per d
6. and differential time mode with mainframe alternate or chopped operation 2 15 Operating Instructions 7B15 NOTE If there is excessive jitter in the delayed sweep display refer to the Triggered Delayed Sweep Magnification discussion Turn the DELAY TIME and delta TIME control s to position the intensified zone s for the precise time interval to be measured using the magnified delayed B sweep waveform s See the examples in Figure 2 10 NOTE For a better look at the delayed B sweep waveform set the mainframe to the B horizontal mode and the amplifier unit deflection factor to increase the display amplitude Do not change the 7815 TIME DIV setting d Read the desired time interval directly on the crt readout 7 To examine an event that occurs within a selected time interval after a known delay time in the delay time mode a Perform the procedures in steps 1 through 4 b Set the appropriate triggering position deflection factor and sweep rate controls for the desired dual trace display See the example in Figure 2 11 NOTE If there is excessive jitter in the delayed B sweep display refer to the Triggered Delayed Sweep Magnification discussion 100 us 10 us KNOWN DELAY TIME ae 1 1l INTENSIFIED ZONE peepee KNOWN DELAY TIME 500 0 us c 1960 38 Figure 2 11 Examining an event that occurs within a selected time interval after a know
7. display produced by 7B15 in the A horizontal compartment Delayed sweep display produced by companion time base unit in the B horizontal compartment Delay time measurements must be made with the B DELAY MODE switch set to B STARTS AFTER DLY When the B DELAY MODE switch is set to B TRIGGERABLE AFTER DLY the delayed sweep starts with the first trigger pulse after the delay time shown on the crt readout Therefore precision time measurements cannot be made in this mode because the time delay is only partially dependent on the DELAY TIME control The crt readout displays the greater than symboli gt preceding the delay time when operating in the B TRIGGERABLE AFTER DLY mode to indicate that the delay time is uncalibrated However the B TRIGGERABLE AFTER DLY mode is useful for triggering on waveforms with excessive jitter A TIME OPERATION The A TIME delaying mode provides the best means of making differential time measurements The 7B15 can delay a companion time base unit at 2 separate delay times At the end of the first delay time determined by the 7B15 DELAY TIME control and TIME DIV switch an 2 9 Operating Instructions 7B15 intensified zone is provided on the delaying sweep trace Further a separate delayed sweep trace corresponding to the first intensified zone is provided At the end of the second delay time determined by the 7B15 TIME DIV switch the DELAY TIME and A TIME controls a second intensified zone a
8. the ES Tel eS CRINES MAG X10 1960 16 Figure 2 4 Effect of sweep magnifier on crt display companion time base unit runs see Fig 2 5 A delayed sweep trace is provided by the companion time base unit corresponding to the intensified zone on the delaying trace at the sweep rate set by the time div switch of the companion time base unit see Fig 2 5 The delay time between the triggering event which starts the delaying sweep trace and the start of the intensified zone and corresponding delayed sweep is determined by the 7B15 TIME DIV switch and DELAY TIME control The amount of calibrated delay time is displayed on the crt readout To view the delaying sweep trace intensified display set the mainframe horizontal mode switch to A to view the corresponding delayed sweep trace set the mainframe horizontal mode switch to B To view the delaying trace intensified and the corresponding delayed sweep trace on the same display set the mainframe horizontal mode switch to alternate or chop Triggering for the delaying sweep trace is controlled by the 7815 TRIGGERING controls Triggering for the intensified zone on the delaying sweep trace and the corresponding delayed sweep trace is controlled by the triggering controls of the companion time base unit when the 7B15 is in the B TRIGGERABLE AFTER DLY mode Operating Instructions 7B15 INTENSIFIED PORTION 1960 17 Figure 2 5 Delaying sweep
9. the delaying A sweep in the delay time mode with mainframe alternate or chopped horizontal operation c Turn the DELAY TIME control to position the intensified zone to the portion of the delaying A sweep waveform to be magnified d Set the delayed B sweep unit sweep rate to select the desired duration of the magnified display as indicated by the length of the intensified zone e Observe the magnified display on the delayed B sweep See Figure 2 9 NOTE For a better look at the delayed sweep waveform set the mainframe to the B horizontal mode and the amplifier plug in unit deflection factor to increase the display amplitude Do not change the 27815 TIME DIV setting f Determine apparent magnification by dividing the 7B15 TIME DIV setting by the delayed sweep unit sweep rate setting Example The apparent magnification of the delayed B sweep shown in Figure 2 9 with a 7B15 TIME DIV setting of 1 millisecond and a delayed sweep unit sweep rate setting of 1 microsecond is 7815 TIME DIV setting Apparent B Sweep Time Div setting Magnification Substituting values Apparent 1X 10 1 100 Magnification 1X 10 The apparent magnification of the delayed sweep display is 100 times the delaying A sweep display 6 To make more accurate time interval measurements the delay time or A differential time mode START OF INTENSIFIED ZONE TIME INTERVAL MEASU
10. 0 to MAG X1 Position Range POSITION Controls fully CW Start of sweep must be to right of graticule center at 1 ms div End of sweep must be left of graticule center at 1 ms div c aaae POSITION Controls fully CCW Some mainframes limit fastest calibrated sweep rate 2200 ps div is measured over any 5 divisions within the center 8 divisions 1 2 e General Information 7B15 TABLE 1 1 Electrical Characteristics Characteristics Performance Requirement VARIABLE TIME DELAY Range Accuracy 20 ms div to 100 ns div 15 to 35 C 0 to 50 C TRACE SEP Range DELAY TIME Range Jitter 0 2 s div to 50 us div 20 to 100 ns div Absolute Delay Accuracy Start of delayed sweep with respect to start of delaying sweep O to 50 C 0 2 s div to 10 us div Differential Measurement Accuracy Measure ment is made by subtracting 2 delay time readings 0 2 s div to 100 ns div O to 50 C Trigger Sensitivity for Repetitive Signals Coupling AC AC LF REJ AC HF REJ DC TRIGGERING 0 0 to at least 9 0 times TIME DIV setting Within 0 596 of Measurement 3 digits Within 0 596 of Measurement 4 digits Functional only in the A TIME Mode when alternating or chopping between timebase units The second delayed sweep display can be vertically positioned at least 3 divisions below the first delayed sweep display when the mainframe
11. 5 SERVICING SAFETY SUMMARY FOR QUALIFIED SERVICE PERSONNEL ONLY Refer also to the preceding Operators Safety Summary The following safety precautions which appear in the servicing information sections of this manual This Servicing Safety Summary is in addition to the Operators Safety Summary given previously WARNING DO NOT SERVICE ALONE E Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present DISCONNECT INSTRUMENT POWER To avoid electric shock disconnect the instrument from the power source before removing protective panels soldering or replacing components SILICONE GREASE HANDLING Handie silicone grease with care Avoid getting the silicone grease in your eyes Wash hands thoroughly after use CAUTI on AVOID EXCESSIVE MOISTURE Circuit boards and components must be dry before applying power to prevent damage from electrical arcing EXERCISE CARE WHEN CHECKING DIODES When checking diodes do not use an ohmmeter scale that has a high internal current since high currents may damage the diodes under test EXERCISE CARE WHEN SOLDERING ON MULTI LAYER BOARDS All but the Readout circuit board in the instrument are multi layer type boards with a conductive path laminated between the top and bottom board layers All soldering on these boards should be done with extreme care to prevent breaking the connections to this center conductor O
12. A time from the start of the first to the start of the second intensified zones By selecting the mainframe alternate or chopped horizontal operation the delaying A sweep and either the first delayed sweep interval delay time mode or both delayed sweep intervals A time mode be displayed simultaneously Since the delayed sweep s can be displayed at a higher magnification than is available with the MAG switch more precise selection of time intervals is possible The following procedures provide instructions for making several types of time interval measurements in the delay time and delta differential time modes TIME INTERVAL MEASUREMENTS DELAY TIME MODE Perform the following procedure to measure the time from a triggering event start of sweep to any point on a displayed waveform 1 Install the 7B15 in the mainframe horizontal compartment and a companion time base unit in the B horizontal compartment 2 Set the 7B15 controls as follows B DELAY MODE B STARTS AFTER DLY button in MAG A anes erat e 1 button in HOLD OFF 2222555 MIN fully counterclockwise TRACE SEP OFF fully clockwise VARIABLE TIME DIV CALIBRATED knob in 3 Connect the signal to be measured to the vertical plug in unit input 4 Set the mainframe for the A horizontal mode to display the 7815 and the vertical mode to display the vertical plug in unit 5 Set the
13. RANGE At least and 3 5 V checked on 1 kHz sine wave Maximum Safe Input BEEN I 1 Megohm Input 250 V dc plus peak 50 Ohm Input 1 Watt average Input R and C a i 1 Megohm input 1 MQ within 5 20 pf within 10 50 Ohm input 50 2 within 296 Trigger Holdoff Time Minimum Holdoff Setting 0 2 s div to 50 ms div 40 ms or less 20 ms div to 2 us div 2times TIME DIV setting or less 1 us div to 2 ns div 2 0 us or less Maximum Holdoff Setting 0 2 s div to 50 ms div 400 ms or greater 20 ms div to 2 us div 20 times TIME DIV setting or greater 1 us div to 0 5 us div 20 0 us or greater 0 2 us div to 2 ns div 6 0 us or greater SPerformance requirement not checked in the manual 1 4 REV JUN 1982 General Information 7B15 TABLE 1 2 Environmental Characteristics Refer to the Specification section of the associated mainframe manual TABLE 1 3 Physical Characteristics Net Weight Approximately 2 6 pounds 1 2 kilogram Dimensions See Figure 1 2 dimensional drawing STANDARD ACCESSORIES E eco Operators Manual pee ERIGI Deine za ke dd instruction Manual OVERALL DIMENSIONS MEASURED AT MAXIMUM POINTS 2 8 12 5 7 1 ed 8 31 7 2 2 14 5 36 9 NOTE TOP FIGURES IN INCHES LOWER FIGURES IN CENTIMETERS 1985 5 Figue 1 2 7 15 dimensional drawing Section 2 7B15 OPERATING IN
14. REMENT FROM A TRIGGERING EVENT START OF SWEEP IN THE DELAY TIME MODE TIME INTERVAL 100 us eA START OF INTENSIFIED TIME INTERVAL A 300 0 us TIME INTERVAL MEASUREMENT BETWEEN TWO POINTS ON A COMPLEX WAVEFORM IN THE DIFFERENTIAL TIME MODE Operating Instructions 7B15 a Perform the procedures in steps 1 through 4 NOTE The remaining steps of this procedure apply for both delay time and A differential time measurements For A differential time operation the 7B 15 TRACE SEP control must be turned counterclockwise out of the OFF detent position The TIME control then positions the second intensified zone and the DELAY TIME control positions the first intensified zone Parentheses are used to indicate the instructions that apply only to A differential time operation b Set the appropriate triggering position deflection factor and sweep rate controls for the desired dual trace display See the examples in Figure 2 10 TIME INTERVAL START OF INTENSIFIED TIME INTERVAL mm A 150 0 us TIME INTERVAL MEASUREMENT BETWEEN TWO PULSES iN THE DIFFERENTIAL TIME MODE TIME PUER Uae IEEE TEE ZNT ANTAN SONA START OF INTENSIFIED TIME INTERVAL gt A 20 00 us TIME INTERVAL MEASUREMENT BETWEEN TWO IDENTI CAL POINTS ON A SINE WAVE IN THE DIFFERENTIAL TIME MODE 1960 37 Figure 2 10 Time interval measurements in the delay time
15. STRUCTIONS The 7B15 Time Base unit operates with a Tektronix 7100 7700 7800 or 7900 series oscilloscope mainframe and a 7A series amplifier unit to form a complete oscilloscope system This section describes the operation of the front panel controis and connectors provides detailed operating information an operators checkout procedure basic applications for this instrument CONTROLS CONNECTORS AND INDICATORS All controls connectors and indicators required for the operation of the time base unit are located on the front panel Figure 2 1 provides a brief description of all front panel controls connectors and indicators More detailed information is given in the Detailed Operating Information portion of this section OPERATORS CHECKOUT The following procedures are provided for checking basic instrument functions Refer to the description of the controls connectors and indicators while performing this procedure If performing the functional check procedure reveals a malfunction possible maladjustment first check the operation of the associated plug in units then refer to the instruction manual for maintenance and adjustment procedures SETUP PROCEDURE 1 Install the 7B15 in the A horizontal compartment of the mainframe 2 Install an amplifier plug in unit in a vertical compartment 3 Set the 7B15 controls as follows SLOPE dap MODE NAE WIE TE VE NR AUTO
16. TRIGGERING controls for a stable display see General Operating Information in this section for selecting proper triggering 6 Set the vertical deflection factor and 7B15 sweep rate for the desired display See the example in Figure 2 7 7 Set the delayed B unit sweep rate for about a 0 5 division intensified zone 2 12 8 Rotate the DELAY TIME control to position the leading edge of the intensified zone at the point on the displayed waveform where the desired time interval ends 9 Read the time interval from the start of the sweep to the leading edge of the intensified zone directly on the crt readout see Figure 2 7 DIFFERENTIAL TIME INTERVAL MEASUREMENTS DELTA TIME MODE Perform the following procedure to measure the time interval between any two selected points on a waveform This procedure can be used to measure the rise time fall time period frequency or pulse width of a displayed waveform 1 Install the 7B15 in the mainframe A horizontal compartment and a companion time base unit in the B horizontal compartment 2 Set the 7B15 controls as follows B DELAY MODE B STARTS AFTER DLY button in REFER E X1 button in HOLD MIN fully counterclockwise TRACE SEP t SP OFF fully clockwise VARIABLE TIME DIV Calibrated knob in 3 Connect the signal to be measured to the vertical plug in unit input 4 Set the mainframe for the A horizontal mo
17. Tektronix COMMITTED TO EXCELLENCE PLEASE CHECK FOR CHANGE INFORMATION AT THE REAR OF THIS MANUAL 7B15 DELAYING TIME BASE INSTRUCTION MANUAL Tektronix Inc P O Box 500 Beaverton Oregon 97077 070 2318 00 First Printing OCT 1978 Product Group 42 Revised JUN 1985 Serial Number Copyright 1978 Tektronix Inc All rights reserved Contents of this publication may not be reproduced in any form without the written permission of Tektronix inc Products of Tektronix inc and its subsidiaries are covered by U S and foreign patents and or pending patents TEKTRONIX SCOPE MOBILE and registered trademarks of Tektronix inc TELEQUIPMENT is a registered trademark of Tektronix U K Limited Printed in U S A Specification and price change privileges are reserved INSTRUMENT SERIAL NUMBERS Each instrument has a serial number on a insert tag or stamped on the chassis The first number or letter designates the country of manufacture The last five digits of the serial number are assigned sequentially and are unique to each instrument Those manufactured in the United States have six unique digits The country of manufacture is identified as follows B000000 Tektronix Inc Beaverton Oregon USA 100000 Tektronix Guernsey Ltd Channel Islands 200000 Tektronix United Kingdom Ltd London 300000 Sony Tektronix Japan 700000 Tektronix Holland NV Heerenveen The Netherlands 7B1
18. ation APPLICATIONS The 7B15 is designed primarily for use with a companion time base unit in a readout equipped mainframe to make delayedsweep time interval measurements The 7B15 can also be used as an independent non delaying time base The following procedures provide instructions for making several delayed sweep time interval measurements using the delay time and A differential time modes These procedures provide enough detail to enable the operator to adapt them to other related time interval measurements Contact your Tektronix Field Office or representative for assistance in making measurements not described in this manual DELAYED SWEEP MEASUREMENTS Complex signals often consist of a number of individual events of differing amplitudes Since the trigger circuits are sensitive only to changes in signal amplitude a stable display can normally be obtained only when the sweep is triggered by the event s having the greatest amplitude However this may not produce the desired display of a lower amplitude portion which follows the triggering event The delayed sweep feature provides a means of delaying the start of the delayed sweep by a selected amount following the event which triggers the sweep generator Then the part of the waveform which contains the information of interest can be displayed at the delayed sweep rate with higher apparent magnification than is provided by the MAG switch The delayed sweep feature can al
19. brated position and the MAG switch set to X1 to obtain the sweep rate indicated by the TIME DIV switch However the mainframe crt readout will display the appropriate sweep rate The VARIABLE TIME DIV control includes a two position switch to determine if the sweep rate is calibrated or uncalibrated When the VARIABLE control is pressed in it is inoperative and the sweep rate is calibrated When pressed and released outward the VARIABLE control is activated for uncalibrated sweep rates to at least the sweep rate of the next slower position A calibrated sweep rate can be obtained in any position of the VARIABLE control by pressing the VARIABLE control This feature is particularly useful when a specific uncalibrated sweep rate has been obtained and it is desired to switch between calibrated and uncalibrated displays TIME MEASUREMENT When making time measurements from the graticule the area between the second and tenth vertical lines of the graticule provides the most linear time measurements see Fig 2 3 Position the start of the timing area to the second vertical line and adjust the TIME DIV switch so the end of the timing area falls between the second and tenth vertical lines SWEEP MAGNIFICATION The sweep magnifier can be used to expand the display by a factor of 10 The center division of the unmagnified display is the portion visible on the crt in the magnified 2 8 SECOND VERTICAL TENTH VERTICAL LINE LINE
20. de externally trigger the delayed B sweep INDEPENDENT TIME INTERVAL MEASUREMENTS The 7B15 is designed primarily for use with a companion time base unit in 7100 7700 7800 or 7900 series oscilloscope mainframes with two horizontal compartments and crt readout However the 7B15 also be used as an independent nondelaying time base e g in a compatible mainframe with one horizontal compartment To operate the 7B15 as an independent time base for time interval measurements press the INDEPENDENT button and obtain the desired display as described in step 2 through 6 of the Time Interval Measurements Delay Time Mode procedure Measure time intervals by multiplying the horizontal distance in divisions between the desired measurement points times the TIME DIV switch setting
21. de to display the 7B15 and the vertical mode to display the vertical plug in unit 500 mV ae ae ee BENE FE ae 1960 34 Figure 2 7 Measuring time intervals from a triggering event start of sweep to any point on a waveform REV JUN 1985 5 Set the TRIGGERING controls for a stable display see General Operating Information in this section for selection of proper triggering 6 Set the appropriate triggering position deflection factor and sweep rate controls to obtain the desired display See the examples in Figure 2 8 7 Adjust the DELAY TIME control to position the leading edge of the first intensified zone to the beginning of the time interval to be measured see Fig 2 8 point A 8 Turn the TRACE SEP control counterclockwise just out of the OFF detent position to obtain a second intensified zone delta time mode on the display RISE TIME MEASURED FROM 10 90 POINTS RISE TIME 00 50 us ENR FREQUENCY PERIOD PERIOD 0 200 us Operating Instructions 7B15 9 Adjust the A TIME control to position the leading edge of the second intensified zone to the end of the time interval to be measured see Fig 2 8 point B 10 Read the time interval between the intensified zones directly from the crt readout NOTE For more accurate t me interval measurements with a dual trace magnified display refer to the Delayed Sweep Magnification procedure FALL TIME
22. display a companion time base unit must be installed in the B horizontal compartment of the mainframe 1 Obtain a display as described in the preceding Normal Sweep procedure 2 Press the B STARTS AFTER DELAY button 3 Set the mainframe horizontal mode for chopped operation 4 Set the companion time base unit sweep rate for O 1 milisecond division and triggering for auto mode coupling internal source and slope 5 Adjust the mainframe B sweep intensity and check for an intensified zone about 1 division wide on the delaying A sweep display Also note that the delayed B sweep provides an expanded display of the intensified portion of the delaying sweep 6 Position the start of the delaying A sweep to the left edge of the graticule 7 Adjust the DELAY TIME control for a crt readout bottom division of crt graticule of 5 000 ms Check that the left edge of the intensified zone is at the graticule center line 8 Set the 7B15 TIME DIV switch to 5 ms and the delayed B sweep unit sweep rate to 20 microseconds division 9 Turn the DELAY TIME control fully counterclockwise to position the intensified zone near the front corner of the first square wave cycle Press the B TRIGGERABLE AFTER DLY button and check that the intensified zone moves to the front corner of the next displayed square wave A Differential Time Perform the following procedure to obtain a A differential time display and to de
23. e trace occurs and that the READY indicator extinguishes when the mainframe calibrator signal is reconnected to the amplifier plug in unit input DETAILED OPERATING INFORMATION Triggering Switch Logic The MODE COUPLING and SOURCE push buttons of the TRIGGERING switches are arranged in a sequence which places the most often used position at the top of each vertical row of push buttons With this arrangement a stable display can usually be obtained by pressing the top push buttons AUTO AC INT When an adequate trigger signal is applied and the LEVEL control is correctly set _ the unit is triggered as indicated by the illuminated TRIG D light If the TRIG D light is not on the LEVEL control is either at a setting outside the range of the trigger signal applied to this unit from the vertical unit the trigger signal amplitude is inadequate or its frequency is below the lower frequency limit of the AC COUPLING switch position If the desired display is not obtained with these buttons pushed in other selections must be made Refer to the following discussions or the instruction manuals for the associated oscilloscope mainframe and vertical unit s for more information TRIGGERING MODES The MODE push button switches select the mode in which the sweep is triggered Auto The AUTO MODE provides a triggered display with the correct setting of the LEVEL control whenever an adequate trigger signal is applied see Trigger L
24. ed abbreviations Instrument option information is located in section 6 of the instruction Manual INSTALLATION The time base unit is designed to operate in the horizontal plug in compartment of the mainframe This instrument can also be installed in a vertical plug in compartment to provide a vertical sweep on the crt However when used in this manner there are no internal triggering or retrace blanking provisions and the unit may not meet specifications To install the unit in a plug in compartment align the upper and lower rails of the plug in with the mainframe tracks and push it in until it fits firmly into the compartment The front panel of the unit should be flush with the front panel of the mainframe Even though the gain of the mainframe is standardized the sweep calibration of the unit should be checked when installed The procedure for checking the unit is given under Sweep Functions in the Operators Checkout procedure in section 2 To remove the unit pull the release latch see Fig 1 1 to disengage the unit from the mainframe and pull it out of the plug in compartment INSTRUMENT PACKAGING H this instrument is to be shipped for long distances by commercial means of transportation it is recommended that it be repackaged in the original manner for maximum protection The original shipping carton should be saved and used for this purpose If more information is needed contact your local Tektronix Field Office o
25. ep mode to photograph waveforms the graticule may have to be photographed separately in the normal manner to prevent over exposing the film Be sure the camera system is well protected against stray light or operate the system in a 2 5 Operating instructions 7B15 darkened room For repetitive waveforms press the SINGLE SWP RESET button only once for each waveform unless the signal is completely symmetrical Otherwise 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 techniques is given in the appropriate camera instruction manual TRIGGER COUPLING The TRIGGERING COUPLING push buttons select the method in which the trigger signal is connected to the trigger circuits Each position permits selection or rejection of some frequency components of the signal which triggers the sweep Alternating Current AC COUPLING blocks the dc component of the trigger signal Signals with low frequency components below 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 Alternating Current Low Frequency Rejection AC LF REJ COUPLING rejects dc and attenuates low frequency trigger signa
26. evel discussions The TRIG D light indicates when the display is triggered 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 rate indicated by the TIME DIV switch TRIG D indicator off An adequate trigger signal ends the free running condition and a triggered display is presented The sweep also free runs at the rate indicated by the TIME DIV switch when the LEVEL control is at a setting outside the Operating instructions 7B15 amplitude range of the trigger signal This type of free running display is useful when it is desired to measure only the peak to peak amplitude of a signal without observing the waveshape such bandwidth measurements Hf Sync The HF SYNC mode provides a triggered display with the correct setting of the LEVEL control whenever a high frequency 100 MHz or higher low amplitude signal is applied This mode is most useful when the incoming signal is too small to produce stable triggering in the AUTO or NORMAL modes The HF SYNC mode increases trigger sensitivity and provides automatic trigger amplifier centering for optimum triggering under these conditions Normal The NORM MODE provides a triggered display with the correct setting of the LEVEL control whenever an adequate trigger signal is applied The TRIG D light indicates when the display is triggered The normal trigger
27. ing changes due to the differences in sensitivity of mainframes in which the 7815 may he used EXTERNAL TRIGGER INPUT EXT TRIG Button Selects input impedance EXT TRIG Connector Connector BNC type provides input for external trigger signals SWEEP MODE B DELAY MODE Pushbuttons Selects independent or delaying sweep operation in the B STARTS AFTER DLY and B TRIGGERABLE AFTER DLY delaying sweep modes the DELAY TIME and A TIME functions are activated There will be a 2 division vertical shift of the trace when switching from INDEPENDENT to B STARTS AFTER DLY DELAY TIME DELAY TIME Control Provides variable delay time before the start of the delayed sweep produced by companion time base unit TRACE SEP Control and Switch Enables A TIME functions and provides vertical separation of the delayed sweep traces TIME operation A TIME Controi Provides differential time measurements between 2 selected intensified zones on the delaying sweep trace Two delayed sweep traces corresponding to the intensified zones are displayed by the companion time base unit Differential time is displayed on the crt readout 2319 03 Figure 2 1 Cont Front panel controls connectors and indicators 2 3 Operating Instructions 7B15 Delaying And Delayed Sweep Perform the following procedure to obtain delaying and delayed sweep displays and to demonstrate the function of the related controls To obtain a delayed sweep
28. ithout resetting the TRIGGERING controls The 1MQ OUT 500 push button provides a convenient means of selecting external trigger input impedance Pushing the button in sets the amplifier input impedance to 1 MQ and the OUT position provides 500 input impedance TRIGGER SLOPE The TRIGGERING SLOPE switch concentric with the TRIGGERING LEVEL control determines whether the trigger circuit responds on the positive or negative going portion of the trigger signal When the SLOPE switch is in the positive going position the display starts on the positive going portion of the waveform see Fig 2 2 When several cycles of a signal appear in the display the setting of the SLOPE switch is often unimportant However if only a certain portion of a cycle is to be displayed correct setting of the SLOPE switch is important to provide a display that starts on the desired slope of the input signal Operating instructions 7815 SLOPE THEE N D LACE ALL LL UL AT VA LIU M VIY MV TERT TRIS D LEVEL 2 SLOPE LEVEL CRT DISPLAY OBTAINED WITH SLOPE SWITCH SET TO POSITIVE E Dol died SLOPE Chm ALIA ANA LE ULL DL LLL JU MIL IM MIA E E EM X HT sich MM TER M Mie amem uasa ru mue HMM aa PUn HMM ais Memon
29. ivision If necessary adjust the front panel SWP CAL screwdriver adjustment for one complete cycle per division over the center 8 graticule divisions Be sure that the timing of the mainframe calibrator signal is accurate to within 0 25 20 to 30 8 Press to release the VARIABLE CAL IN control Turn the VARIABLE CAL IN control fully counterclockwise and note that the displayed sweep rate changes to at least the next slower TIME DIV switch setting i e 2 milliseconds division Press the VARIABLE CAL IN knob in to the calibrated position Magnified Sweep Perform the following procedure to obtain a X10 magnified display and to demonstrate the function of the related controls 1 Obtain a one cycle per division display as described in the preceding Normal Sweep procedure 2 Press to release the MAG button X10 Note that the unmagnified display within the center division of the graticule is magnified to about 10 divisions 3 Press the MAG button X1 2 1 Operating Instructions 7B15 00000 Q SLOPE fries TRIGGERING LEVEL b 1 couPLNG SOURCE AUTO AC INT LI BF SYNC AC LF RES LINE L LI NORM ACHF RES EXT Li LI LI SINGLE SWP oC HOLD O j RESET SZ MAG MODE iN INDEPENDENT OUT x10 VARIABLE CAL IN TIME DIV 4 B STARTS AFTER DEY TRIGGERABLE AFTER DLY DELAY TIME eG 250v
30. ls below about 50 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 linefrequency 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 Alternating Current High Frequency Rejection AC HF REJ COUPLING passes all low frequency signals between about 30 hertz and 30 kilohertz Dc is rejected and signals outside the above range are attenuated When triggering from complex waveforms this position is useful to provide a stable display of the low frequency components Direct Current DC COUPLING can be used to provide stable triggering from low frequency signals which would be attenuated in other COUPLING switch positions DC COUPLING can 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 vertical plug in unit position contro affects the triggering point TRIGGER SOURCE The TRIGGERING SOURCE push buttons select the source of the trigger signal which is connected to the trigger circuits 2 6 internal The INT position connects the trigger signal from the vertical plug in unit Further selection of the internal trigger signal may be provided by the vertical plug in unit or b
31. me as given for delta Time Operation The 7B15 must be installed in the A horizontal compartment and the companion time base unit must be installed in the B horizontal compartment as with conventional 4 plug in compartment mainframes Set the horizontal mode switch so that the 7B15 provides horizontal deflection for one beam and the companion time base unit provides horizontal deflection for the other beam Apply the input signal to the desired vertical plug in unit and select that unit for vertical deflection of both beams Operation of the TIME mode in dual beam mainframes with a dedicated vertical system differs slightly from conventional dual beam mainframes with vertical mode switches The plug in unit in the left vertical compartment provides vertical deflection of beam 1 and the plug in unit in the right vertical compartment provides vertical deflection for beam 2 Therefore the input signal must be applied to the units in both the left and right vertical compartments for A TIME operation 2 10 MAINFRAME OPERATING MODES The 7B15 can also be operated either as an independent time base in any Tektronix 7100 7700 7800 or 7900 series mainframes or as a delayed sweep unit B DELAY MODE switch set to INDEPENDENT in those mainframes that have two horizontal compartments A companion delaying time base unit e g another 7B15 is required for delayed sweep operation Refer to Applications in this section for additional inform
32. me mode 1Instali the 7815 in the mainframe horizontal compartment and a companion time base unit in the B horizontal compartment 2 Set the 7B15 controls as follows B DELAY MODE B STARTS AFTER DLY button in NUNG 1 button HOLD MIN fully counterclockwise VARIABLE TIME DIV Calibrated knob TRACE SEP OFF fully clockwise 3 Connect the signal to be measured to the vertical unit input 4 Set the mainframe horizontal mode for alternate or chopped operation see oscilloscope mainframe instruction manual for discussion of alternate or chopped operation 5 To magnify a selected segment of the delaying A sweep waveform and determine apparent magnification in the delay time mode a Perform the procedure in step 1 through 4 b Set the appropriate triggering position deflection factor and sweep rate controls for the desired dual trace display See the example in Figure 2 9 NOTE If there is excessive jitter in the delayed B sweep display refer to the Triggered Delayed Sweep Magnification discussion 2 14 AN WEN SUBE ole al THIS PORTION OF THE DISPLAY CANNOT NORMALLY BE EXAMINED IN DETAIL BECAUSE THE DELAYING SWEEP 1S TRIGGERED ON THE LARGER AMPLITUDE SIGNALS AT THE START OF THE DISPLAY 1960 36 Figure 2 9 Magnifying a selected segment of
33. mode must be used to produce triggered displays with trigger repetition rates below about 30 hertz When the TRIG D light is off no trace is displayed Single Sweep When the signal to be displayed is not repetitive or varies in in amplitude waveshape or repetition rate a conventional repetitive type display may produce an unstable presentation Under these circumstances a stable display can often be obtained by using the single sweep feature of this unit The single sweep mode is also useful to photograph 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 the other TRIGGERING controls press the SINGLE SWP RESET button A single trace is presented each time this button is pressed Further sweeps cannot be presented until the SINGLE SWP RESET button is pressed again If the displayed signal is a complex waveform composed of varying amplitude pulses 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 SWP RESET button 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 by using a viewing hood as recommended in the mainframe instruction manual When using the single swe
34. monstrate the function of the related controls 1 Obtain a delaying A and delayed B sweep display as described in steps 1 through 4 of the preceding Delaying and Delayed Sweep procedure 2 Turn the TRACE SEP control counterclockwise out of the OFF detent position 3 Set the DELAY TIME and A TIME controls to the fully counterclockwise position Check for two delayed sweeps and note that the crt readout bottom right of crt is 0 000 ms 4 Slowly turn the A TIME control clockwise and note that a second intensified zone moves across the delaying sweep display and the crt readout indicates the differential time between the left edge of the stationary intensified zone and the left edge of the second intensified zone Also note that the lower delayed sweep is an expanded display of the second intensified zone TRIGGERING FUNCTIONS Perform the following procedure to obtain a triggered sweep and to demonstrate the functions of the related controls 1 Obtain a display as described in the preceding Normal Sweep procedure 2 Turn the LEVEL control fully counterclockwise to obtain a free running sweep 3 Slowly turn the HOLD OFF control clockwise and note that a stable display can be obtained at several positions of the HOLD OFF control Return the HOLD OFF control to the fully counterclockwise MIN position NOTE The HOLD OFF control varies the sweep hold off time which effectively changes the repe
35. n delay time in the delay time mode 2 16 c Adjust the DELAY TIME control for the known delay time as indicated on the crt readout d Set the delayed B sweep rate i e the intensified E zone length for the desired time interval after the delay time selected in part c Multiply the delayed B sweep rate by 10 to determine the actual displayed delayed B sweep time interval See the example in Figure 2 11 e Observe the magnified event to be examined on the delayed B sweep NOTE For a better look at the delayed B sweep waveform set the mainframe to the B horizontal mode and the amplifier plug in unit deflection factor to increase the display amplitude Do not change the 7B15 TIME DIV setting TRIGGERED DELAYED SWEEP MAGNIFICATION The displayed waveform may have excessive jitter at the faster delayed sweep rate settings The TRIGGERABLE AFTER DLY position button in of the B DELAY MODE switch provides a more stable display since the delayed B sweep display is then triggered at the same point each time The crt readout is uncalibrated in this mode as indicated by the symbol Inability to obtain the intensified zone s on the delaying A sweep display indicates that the delayed B sweep triggering controls are incorrectly set or that the input signal does not meet triggering requirements If the condition cannot be corrected with the triggering controls or by increasing the display amplitu
36. nd ed Sul aii Ls PROVIDES VERTI CAL POSITIONING OF DELAYED SWEEP TRACES WITH RE SPECT TO DELAY ING SWEEP TRACE HORIZONTAL MODE SWITCH SET TO ALT OR CHOP FOR A TIME OPERATION CONTROLS TRIG GERING OF DELAY ING SWEEP TRACE E ice Tw CONTROLS TRIG r i a t 22 GERING OF INTEN SIFIED ZONES AND DELAYED SWEEP TRACES WHEN B DELAY MODE SWITCH S SET TO B TRIGGERABLE AFTER DLY AMPLIFIER uum UNIT 5 DETERMINES SWEEP RATE OF INTENSIFIED ZONES AND DE LAYED SWEEP TRACES DETERMINES THE AMOUNT OF DELAY ENABLES A TIME OPERATION AND TIME FROM THE START DETERMINES DIF OF THE DELAYING FERENTIAL MEASURE SWEEP TRACE TO THE MENT AND CORRES START OF THE FIRST PONDING DIFFEREN INTENSIFIED ZONE TIAL TIME READOUT AND CORRESPONDING FIRST DELAYED SWEEP TRACE DETERMINES SWEEP RATE OF DELAYING SWEEP TRACE PROVIDES VERTI CAL POSITIONING OF SECOND DELAYED SWEEP TRACE WITH RESPECT TO FIRST DELAYED SWEEP TRACE 1960 21 2319 08 Figure 2 6 Typical Differential Time Operation 2 11 Operating Instructions 7B15 In the A differential time mode the delayed B sweep runs for a second selected interval indicated by a second intensified zone superimposed on the delaying A sweep trace The two intensified zones can be positioned with the DELAY TIME and A TIME controls The crt readout then indicates the differential
37. nd corresponding second delayed sweep trace are displayed see Fig 2 6 The 7B15 must be installed in the A horizontal compartment The companion time base unit must be installed in the B horizontal compartment The TRACE SEP control must be rotated counterclockwise out of the switch detent position for A TIME operation The sweep rate for the delaying sweep trace is determined by the 7B15 TIME DIV switch and the sweep rate of the intensified zones and corresponding delayed sweep display is determined by the sweep rate setting of the companion time base unit The differential time between the start of the first intensified zone and the start of the second intensified zone is displayed on the crt readout see Fig 2 6 A A symbol preceding the delay time readout indicates a differential measurement The greater than symbol following the A symbol indicates that the TIME DIV VARIABLE control is activated or that the B DELAY MODE switch is set to B TRIGGERABLE AFTER DLY and therefore the differential time is uncalibrated The TRACE SEP control vertically positions the second delayed sweep trace with respect to the first delayed sweep trace Vertical positioning of the delayed sweep trace is provided by the vertical separation control on the oscilloscope mainframe A Time Operation In A Dual Beam Oscilloscope Mainframe 7 15 A TIME function is compatible with 7000 series dual beam mainframes and operation is basically the sa
38. nly experienced maintenance T personnel should attempt repair of these boards USE PROPER CLEANING AGENTS Avoid the use of chemical cleaning agents which might damage the plastics used in this instrument Use a non residue type of cleaner preferably isopropyl alcohol totally denatured ethyl alcohol or Freon TF Before using any other type of cleaner consult your Tektronix Service Center or representative DO NOT USE PIN SOCKETS FOR CONNECTION POINTS The spring tension of the pin sockets ensures a good connection between the circuit board and the pin This spring tension can be destroyed by using the pin sockets as a connecting point for spring loaded probe tips alligator clips etc i vi 7B15 7815 Features The 7B15 Delaying Time Base unit provides calibrated sweep rates from 2 seconds to 2 nanoseconds and triggering to 1 Gigahertz for 7100 7700 7800 and 7900 series oscilloscopes The X10 Magnifier increases each sweep rate by a factor of 10 and a VARIABLE control allows continuously variable sweep rates between calibrated steps Variable hold off and alpha numeric readouts are provided Also when operating in the AUTO TRIGGERING MODE a bright baseline trace is displayed in the absence of a trigger signal Other features include independent sweep operation of continuously variable sweep delay DELAY TIME and differen
39. r representative 4 i RELEASE LATCH 11960 13 2319 2 Figure 1 1 Location of release latch 1 1 m General Information 7B15 SPECIFICATION This instrument will meet the electrical characteristics listed in Table 1 1 following complete adjustment The following electrical characteristics are valid over the stated environmental range for instruments calibrated at an ambient temperature of 20 to 30 C and after a twenty minute warmup unless otherwise noted TABLE 1 1 Electrical Characteristics Characteristics Performance Requirement SWEEP GENERATOR Sweep Rates Calibrated Range 0 2 s div to 2 ns div in 25 steps X10 Magnifier extends _ fastest calibrated sweep rate to 0 2 ns div Variable Range Continuously variabie uncalibrated sweep rate to at least 2 5 times the calibrated sweep rate setting Sweep Accuracy with 7104 7900 and 7800 Measured over center 8 displayed divisions SWP CAL is Series Mainframes adjusted at 1 ms div within the 20 to 30 C range 7 15 Delay Mode Switch set to independent 15 to 35 C MAG X10 0 2 s div to 10 ns div 5 ns div and 2 ns div O to 50 C Derate 15 to 35 C accuracy by additional 196 Excluded Portions of Sweep 7104 None 7800 7900 Series First 5 ns Sweep Length At least 10 2 div MAG Registration 0 5 div or less from graticule center when changing from MAG X1
40. so be used to provide rapid and accurate time interval measurements from a triggering event i e the start of the delaying sweep to a selected point or between two selected points on a displayed waveform See General Operating Information in this section for a further discussion of delay time operation In the delay time mode the delayed B sweep runs for a selected interval after the delaying sweep as indicated by an intensified zone superimposed on the delaying A sweep trace The length of the intensified zone indicates the time that the delayed sweep runs and is determined by the delayed B sweep plug in unit sweep rate HME DIV setting The time from the start of the delaying A sweep to the start of the intensified zone i e the start of the delayed sweep can be read directly on the crt readout DIFFERENTIAL MEASUREMENT FIRST INTENSIFIED ZONE DELAYING SWEEP TRACE FIRST DELAYED SWEEP TRACE CORRESPONDING TO FIRST INTEN SIFIED ZONE SECOND DELAYED SWEEP TRACE COR RESPONDING TO SECOND INTENSI FIED ZONE DIFFERENTIAL TIME B DELAY MODE SWITCH SET TO B STARTS AFTER DLY FOR A TIME DIFFERENTIAL MEASUREMENTS INPUT SIGNAL Operating Instructions 7B15 DELAYING SWEEP RATE SECOND INTENSIFIED ZONE DELAYED SWEEP RATE DETERMINES IN TENSITY OF DELAY ING SWEEP TRACE AND INTENSIFIED DETERMINES IN TENSITY OF DE LAYED SWEEP TRACES Mi ux bacon fo
41. tial sweep delay A TIME with a companion time base unit Delay time or differential delay time readout is displayed on the mainframe cathode ray tube Section 1 7B15 GENERAL INFORMATION INTRODUCTION OPERATORS MANUAL The Operators Manual contains information necessary to effectively operate the 7B15 Time Base and is divided into three sections Section 1 provides basic description of the 7B15 with instrument specifications and accessories section 2 contains operating information for the instrument instrument option information is located in section 3 of the manual INSTRUCTION MANUAL The Instruction Manual provides both operating and servicing information for the 7815 Time Base The instruction Manual is divided into nine sections Operating information is covered in the first two sections servicing information for use by qualified service personnel is contained in the remaining seven sections of the manual Schematic diagrams are located at the rear of the manual and can be unfolded for reference while reading other parts of the manual The reference designators and symbols used on the schematics are defined on the first page of the Diagrams and Circuit Board Illustrations section All abbreviations used in this manual with the exception of the parts lists and schematic diagrams comply with the American National institute 1 1 1972 publication The parts lists are computer printouts and use computer suppli
42. tition rate of the horizontal sweep signal However its primary function is to obtain a stable display of complex waveforms which are otherwise difficult to trigger 4 Press the AC AC HF REJ and DC COUPLING buttons for both the and positions of the SLOPE switch and check for a stable display LEVEL control may be adjusted if necessary to obtain a stable display 5 Apply the O 4 voit 1 kilohertz signal from the mainframe calibrator to the amplifier plug in unit and to the EXT TRIG IN connector 6 Press the EXT SOURCE button and set the amplifier plug in unit deflection factor for a 4 division display 7 Press the AC AC HF REJ and DC COUPLING buttons for both the and positions of the SLOPE switch and check for a stable display LEVEL control may be adjusted if necessary for a stable display 8 Press the AC COUPLING INT SOURCE and NORM MODE buttons Adjust the LEVEL control for a stable display 9 Press the AUTO MODE button and adjust the LEVEL control for a free running display 10 Press the NORM MODE button and check for no 27 display 11 Adjust the LEVEL control for a stable display and press the SINGLE SWP MODE button 12 Note that one trace occurs when the SINGLE SWP button is pressed again 13 Disconnect the mainframe calibrator signal from the amplifier plug in unit input and press the SINGLE SWP button Check for no display and note that the READY indicator is lit 14 Note that on
43. vertical trace separation control is centered O 2 or less to at least 9 0 times TIME DIV setting 0 0296 of TIME DIV setting or less 0 03 of TIME DIV setting 100 ps or less Within 0 596 of Delay 5 of TIME DIV setting Within 0 596 of Measurement 4 digits Triggering Frequency Minimum Triggering Range Signal Required Internal 0 5 div External 30 Hz to 250 MHz 250 MHz to 1 GHz 150 mV 50 kHz to 250 MHz 50 mV 250 MHz to 1 GHz 150 mV 30 Hz to 30 kHz 50 mV Dc to 250 MHz 50 mV 250 MHz to 1 GHz 150 mV i The triggering frequency ranges given here are limited to the 3 dB frequency of the oscilloscope vertical system when operating in the Internal mode Will not trigger on sine waves at or below 60 Hz when amplitudes are less than 8 divisions Internal or 3 volts External The Triggering Frequency Range for DC COUPLING applied to frequencies above 30 Hz when operating in the AUTO TRIGGERING MODE 1 3 General information 7B15 TABLE 1 1 CONT Electrical Characteristics Characteristics Performance Requirement Singie Sweep Same as for Repetitive and Pulsed Triggering internal Trigger Jitter 30 ps or less at 1 GHz Operating in HF SYNG MODE AC AC LF REJ or DC 250 MHz to 1 GHz 0 3 div Internal 75 mV External Extemal Trigger npt m LEVEL
44. y the mainframe see the instruction manuals for these instruments 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 position connects a sample of the power line voltage from the mainframe to the trigger circuit 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 component in a complex waveform External The EXT position connects the signal from the EXT TRIG IN connector to the trigger circuit The external 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 either 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 EXT TRIG IN connector through a probe or cable The sweep is then triggered by the same signal at all times and allows amplitude time relationship or waveshape changes of signals at various points in the circuit to be examined w
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