Tektronix 7B53N Instruction Manual Download

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Summary of Contents for 7B53N

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Page 3: ...structions 2 6 Part 1 Performance Check 5 4 Main Sweep 2 6 Index to Part I Performance Check 5 4 Magnified Display 2 6 Preliminary Procedure for Delayed Sweep Display 2 6 Performance Check 5 4 Mixed Sweep Display 2 7 Trigger System Check 5 5 General Operating Instructions 2 7 Horizontal System Check 5 11 Pushbutton Switch Logic 2 7 Output Signals Check 5 17 Triggered Light 2 7 Part 11 Adjustment 5...

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Page 5: ...meet the electrical characteristics listed under Performance Requirement in Table 1 1 fol lowing complete calibration The following electrical char acteristics apply over an ambient temperature range of 0 C to 50 C except as otherwise indicated Warmup time for given accuracy is 20 minutes Characteristic Performance Requirement Supplemental Information Source Internal from associated vertical unit ...

Page 6: ...d with signal amplitudes given under Internal and Ex ternal Trigger Sensitivity above 30 hertz Presents a free running sweep for lower frequencies or in absence of a trigger signal Main Sweep Generator produces only one sweep when triggered Further sweeps are locked out until RESET button is pressed Trigger sensitivity same as given for internal and external sensitivity 1 nanosecond or less at 75 ...

Page 7: ... division of deflection minimum 30 hertz to 10 megahertz increasing to 1 5 divisions at 100 megahertz DC 0 3 division of deflection minimum DC to 10 megahertz increasing to 1 5 divi sions at 100 megahertz External Trigger Sensitivity AC 100 millivolts minimum 30 hertz to 10 Delayed Triggering SOURCE switch megahertz increasing to 500 millivolts at set to EXT 100 megahertz DC 100 millivolts minimum...

Page 8: ...ep rates VARIABLE Sweep Rate Range Continuously variable between calibrated Extends sweep rate to at least 12 5 sweep rates seconds division VARIABLE control internally switchable between Main and Delayed Sweeps Sweep Hold Off Time 5 seconds division to 10 micro 1 5 times the TIM E D IV setting or less seconds division 5 microseconds division to 0 5 2 5 microseconds or less microsecond division No...

Page 9: ...t 0 5 division after start of MAIN sweep display and 0 2 division or 1 microsecond whichever is greater after transition of MAIN to DLY D sweep 10 millivolts division within 10 100 mill ivolts division within 10 1 volt division within 10 Deflection Factor EXT MAG X10 EXT MAG off EXT 10 MAG off Characteristic Performance Requirement Supplemental Information Sweep Linearity Over any 2 division porti...

Page 10: ...least 10 kilohms shunted by 100 picofarads or less Composite Sweep Gate Coupled to associated indicator oscilloscope by way of pin A1 on In Waveshape Rectangular pulse terface circuit board Polarity Positive going Duration DISPLAY MODE MAIN SWP Coincident with the main sweep interval INTEN Coincident with the main sweep interval DLY D SWP Coincident with the delayed sweep in terval MIXED Coinciden...

Page 11: ...total duration coin cident with the delaying sweep interval Ramp duration coincident with the main sweep interval plus the delayed sweep in terval total duration coincident with the delaying sweep interval Auxiliary Gate Waveshape Polarity Duration Composite Sawtooth Waveshape DISPLAY MODE MAIN SWP O Polarity Characteristic INTEN DLY D SWP MIXED Duration DISPLAY MODE MAIN SWP INTEN DLY D SWP MIXED...

Page 12: ...al Modes or as a delayed sweep unit However when the 7B53N is operated as a delayed sweep unit it must be triggered for a CRT display It cannot delay another time base unit but it can delay its own internal delayed sweep Before proceeding with installation it is necessary to check the setting of the internal Variable Selector switch on the right side of the instrument see Fig 2 1 for location The ...

Page 13: ...e LEVEL SLOPE control is outside the amplitude range the trigger repetition rate is outside the fre quency range selected by the COUPLING switch or the trig ger signal is inadequate the sweep free runs at the sweep rate selected by the TIME DIV OR DL Y TIME switch COUPLING NORM Sweep initiated by the applied trigger signal at point se lected by the LEVEL SLOPE control over the frequency range sele...

Page 14: ...s from DC to 100 megahertz Four pushbutton switches to select the trigger source Operating Instructions 71353N LINE Trigger signal obtained in ternally from a sample of the line voltage applied to associated indicator oscilloscope EXT Trigger signal obtained from an external signal applied to the MAIN TRIG IN connector EXT 10 Trigger signal obtained from an external signal applied 2 3 ...

Page 15: ...n pushed in the VARIABLE control is inoperative and the sweep rate is calibrated When pressed and released the knob moves out to activate the VARIABLE control for uncali brated sweep rates The sweep rate in each TIME DIV switch position DISPLAY MODE DELAY TIME MULT Delayed Trigger Controls LEVEL can be reduced at least to the sweep rate of the next slower position The VARIABLE control can be switc...

Page 16: ... fier unit by way of the associ ated indicator oscilloscope Also Front Panel Connectors MAIN TRIG IN DLY D TRIG IN Operating Instructions 71353N connects the Delayed Gate Out signal to the DLY D TRIG IN connector for external use EXT The delayed trigger signal is obtained from an external signal applied to the DLY D TRIG IN connector Front panel BNC connector serving two different input functions ...

Page 17: ...plete function and operation of the unit described in this section before using this procedure Main Sweep The following procedure will provide a stable display for most main sweep applications 2 6 SIMPLIFIED OPERATING INSTRUCTIONS 1 Select the MODE COUPLING and SOURCE push button of the MAIN TRIGGERING switches which fit the requirements of the signal to be displayed 2 Press the MAIN SWP pushbutto...

Page 18: ...uttons are arranged in a sequence which places the most often used position at the top of each series of pushbuttons With this arrangement a stable display can usually be obtained by pressing the top pushbuttons AUTO AC INT and MAIN SWP When an adequate trigger signal is applied the unit is triggered as indicated by the illuminated TRIG D light with the correct setting of the LEVEL SLOPE control I...

Page 19: ... the ambient light level or using a viewing hood as recommended in the indicator oscilloscope instruction manual Non repetitive random signals can be displayed in the single sweep mode by first obtaining the best possible dis 2 8 play in the NORM MODE with a signal which is about the same amplitude and frequency as the random signal Then without changing the other MAIN TRIGGERING controls press th...

Page 20: ...triggering the setting of the vertical unit position controls affects the DC triggering point Fig 2 4 Frequency range of each COUPLING switch position Main Trigger Source Operating Instructions 71353N The MAIN TRIGGERING pushbuttons located below the SOURCE title select the source of the trigger signal which is connected to the main trigger circuits INT In the INT position of the SOURCE switch the...

Page 21: ...e LEVEL SLOPE control is turned clockwise from the line on the positive going slope the displayed waveform starts at a more positive level 2 1 0 Before setting the triggering level the desired SLOPE MODE COUPLING and SOURCE should be selected for MAIN TRIGGERING Then adjust the LEVEL SLOPE control so the displayed waveform starts from the desired point The triggering slope can be changed at any ti...

Page 22: ...in negative slope region TRIG D EVELISLOPE ma mmmomm umummmummm mvxmuuxxmu mmummmmrrrmm ammummummm mmmmmmmmmm NIMENEEMENIN mmmmm youffffmuffm mummummumm offiammmmamm K1 1 VAR M 1 MrEWEENEEN mommommomm Negative slope Fig 2 5 Effect of LEVEL SLOPE control on CRT display AUTO or NORM MODE Operating Instructions 7B53N 2 1 1 ...

Page 23: ... equivalent magnified sweep rate can be determined by dividing the TIME DIV Fig 2 8 Operation of Sweep Magnifier OR DL Y TIME switch setting by 10 For example if the TIME DIV OR DL Y TIME switch is set to 5 us the equi valent magnified sweep rate is 5 nanoseconds division The equivalent magnified sweep rate must be used for all time measurements when the X10 MAG indicator is illuminated The equiva...

Page 24: ...Y MODE switch is a function of both the main and delayed sweeps In this mode the main sweep is displayed at the rate determined by the TIME DIV OR DL Y TIME switch followed by the delayed sweep at a rate determined by the DLY D SWEEP Time Division switch The amount of dis play allocated to each sweep is determined by the setting of the DELAY TIME MULT dial A typical mixed sweep dis play is shown i...

Page 25: ...pe cific measurements Also the following books describe oscilloscope measurement techniques which can be adapted for use with this instrument Harley Carter An Introduction to the Cathode Ray Oscilloscope Philips Technical Library Cleaver Hume Press Ltd London 1960 J Czech Oscilloscope Measuring Technique Philips Technical Library Springer Verlag New York 1965 2 14 Robert G Middleton and L Donald P...

Page 26: ...termining Frequency Measurements Time Duration Measurements To measure time between two points on a waveform use the following procedure 1 Connect the signal to be displayed to the input of the vertical unit 2 Set the Vertical and Horizontal Mode switches on the indicator oscilloscope to display the plug in units used Operating Instructions 71353N 3 Set the Volts Division switch of the vertical un...

Page 27: ... on the indicator oscilloscope to display the plug in unit used 3 Set the Volts Division switch and the Variable Volts Division control of the vertical unit to produce a signal an exact number of divisions in amplitude 4 Center the display about the center horizontal line with the vertical unit Position control 5 Set the MAIN TRIGGERING controls to obtain a stable display 6 Set the TIME DIV OR DL ...

Page 28: ...h and press the Delayed Triggering LEVEL control to the IN RUNS AFTER DL Y TIME position 7 Set the DLY D SWEEP Time Division switch to a setting 1 100 of the TIME DIV OR DL Y TIME sweep rate This produces an intensified portion approximately 0 1 di vision in length NOTE Measurement accuracy will be affected if the LEVEL control setting for MAIN TRIGGERING or the hori zontal POSITION control settin...

Page 29: ...riggered Delayed Sweep Magnification procedure which follows this procedure 1 Connect the signal to be displayed to the input con nector of the vertical unit Set the Vertical and Horizontal Mode switches on the indicator oscilloscope to display the plug in units used 2 1 8 4 Set the TIME DIV OR DL Y TIME switch to a sweep rate which displays the complete waveform see Fig 2 14A 5 Press the INTEN pu...

Page 30: ... controls or by increasing the display amplitude lower Volts Division setting externally trigger the delayed sweep 5 When the correct portion of the display is intensified set the DISPLAY MODE switch to DLY D SWP Slight re adjustment of the Delayed Triggering LEVEL control may be necessary to produce a stable display 6 Measurement and magnification are as described above in Delayed Sweep Magnifica...

Page 31: ...intensified portion with the DELAY TIME MULT dial to the part of the display to be magnified 7 Set the DLY D SWEEP 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 8 Press the DISPLAY MODE switch to DLY D SWP 9 Slight readjustment of the Delayed Triggering LEVEL control may be ...

Page 32: ...ode 7B53N Sweep Stop Comparator One side of this comparator is driven by the main sweep sawtooth signal and the other side is set by the Main Swp Stop adjustment When the sawtooth waveform passes through the setting of the Main Swp Stop adjustment the output of the Sweep Stop Com parator switches to a positive level This positive step is applied to the Main Sweep Holdoff and by way of a small capa...

Page 33: ...INT Fig 3 1 7B53N Simplified Block Diagram ...

Page 34: ...ation of other circuit blocks follows External Horiz Input General CIRCUIT OPERATION Circuit Description 71353N Mixed Sweep Comparator This circuit determines which sweep signal is coupled to the Horiz Output stage First the main sweep sawtooth is coupled through the Mixed Sweep Comparator and the Delayed Sawtooth Gen erator to the Horiz Output stage These stages perform as an operational amplifie...

Page 35: ...igger Preamp selects trigger source and coupling for the Main Trigger Generator and provides am plification for external horizontal signals when the TIME DIV OR DL Y TIME switch is set to AMPL This circuit consists of four stages Trigger Source Switching External Trigger Preamp or External Input Am plifier Balanced to Single Ended Converter and Trigger Coupling Fig 3 2 shows a detailed block diagr...

Page 36: ...y way of pins 8 and 9 and R346 Operation is the same as internal triggering Circuit Description 71353N R330 sets the DC level at pin 10 of U330 which is the negative side of the external trigger differential input This matches the DC balance of the external trigger input of U330 to that of the internal trigger input Balanced to Single Ended Converter The balanced to single ended converter changes ...

Page 37: ... With SLOPE switch S2 in the position the cathode of CR424 is grounded forward biasing CR424 which reverse biases CR423 At the same time the base of 0428 is at 3 6 Fig 3 3 Main Trigger Generator detailed block diagram ground and Q428 is off This causes CR421 to be reverse biased and CR422 is forward biased through Q416 An in creased current is applied to the Trigger TD and Driver circuit through Q...

Page 38: ... 5 V 15 V 1 L__________ 5V i i i LEVEL SLOPE 15 V 5 V n n v I V W CT1 W Fig 3 4 Trigger current path for positive slope triggering Z ...

Page 39: ... ilar to NORM operation except that the sweep is not re current The RESET button must be pressed to view another trace The following circuit description is given with the MAIN TRIGGERING MODE switch pressed to 3 8 NORM Difference in operation for the other two modes is discussed later Main Sweep Start Comparator Q722 Q726 and Q728 comprise the Main Sweep Start comparator In the absence of a trigge...

Page 40: ...DE DISPLAY MODEI Fig 3 5 Main Sweep Generator detailed block diagram M TIME DIV To Composite Sweep Out and Mixed Sweep Comparator Holdoff to Dly d Sweep Trigger Generator Holdoff to Main Trigger Generator ...

Page 41: ...in 19 of U720 enables the Auto Circuit When a repetitive trigger signal above 30 Hz and of adequate amplitude is applied to the Main Sweep Start Comparator and pin 1 of U720 the in ternal Auto Multi at pin 6 of U720 charges towards five volts through C786 and R786 but is discharged by each incoming trigger pulse In the absence of a trigger pulse C786 charges towards 5 V switching pin 6 to its high...

Page 42: ...TRIG IN OR DLY D GATE OUT 5 V Dly d T I l Ext Int SOURCE S18 i 10 Int I I I I l Delayed Gate from Delayed Sweep Start Control Inter Trigger Signal from Vertical Unit Dly d External Trigger Preamp 0508 0512 0516 S10B MAIN Sw 1 S15 IME DIV I DLY D TRIGGER I MODE AMPL I RUNS AFTER Fig 3 6 Delayed Trigger Preamp detailed block diagram Circuit Description 712153N can be triggered An approximate zero vo...

Page 43: ...Level Comparator Q602 0604 Dly d Slope Selector 0616 0618 0828 SLOPE Dly d Delay Gate from Delay Pickoff Dly d Swp Holdoff Dly d Trigger Generator Q654 Q666 Q862 CR670 CR675 DELAYED TRIGGER GENERATOR To Dly d Sweep Holdoff Dly d Sweep Enable 3 12 Dly d Trigger Coupling Fig 3 7 Delayed Trigger Generator detailed block diagram When COUPLING switch S17 is set to DC 0562 is forward biased by way of R5...

Page 44: ...dicator oscilloscope for CRT unblanking Fig 3 8 shows a detailed Dly d Swp Start Multi Dly d Swp Start Control Mixed Swp Comparator Circuit Description 71353N block diagram of the Delayed Sweep Generator and the schematic is shown on diagram 6 at the rear of the manual Q882 and Q886 comprise the Dly d Swp Start Multi This circuit is connected as a bistable multivibrator with Q886 normally conducti...

Page 45: ...888 Q892 Q896 Q898 DISPLAY MODE Aux Z Axis Out Q992 Dly d Swp Stop P O U930 Main Swp Gate Main Sweep Holdoff Dly d Sweep Lockout Multi Q942 Q944 Dly d Sweep Holdoff 0954 Holdoff to Delayed I Trigger Generator S12 DISPLAY MODE A3 B3 Fig 3 8 Delayed Sweep Generator detailed block diagram S10B c TIME DIV 1 DISPLAY MODE v DLY D Composite Sweep Gate Composite Sweep Gate Out Al Out Q922 0924 0928 V Aux ...

Page 46: ... if forward biased and couples the delayed sweep or mixed sweep sawtooth to the base of Q968 Composite Swp Gate Out Aux Z Axis Control Aux Z Axis Out Circuit Description 71353N 0966 and Q968 or Q962 and Q968 depending on DISPLAY MODE setting are connected as an operational amplifier providing a high degree of gain stability The Composite Sweep Gate Out circuit includes Q922 Q924 and Q928 The outpu...

Page 47: ...ept AMPL the 5 volts coupled through CR 113 CR 1016 and R 1016 to the base of Q1006 holds this transistor in saturation Therefore any incoming external horizontal signal is by passed to ground by way of 15 volt supply through Q1006 and U1020D When the TIME D IV DL Y switch is set to AMPL the 5 volts is removed from the base of Q1006 allowing Q1004 and Q1006 to function as an operational amplifier ...

Page 48: ... DC current coupled to the Horiz Out Amp Horiz Out Amp Circuit Description 7853N The Horiz Out Amp includes Q1038 Q1046 and U1034A B C and D U 1034B and U 1034C are connected as an operational amplifer with Rf being R1052 and R i the the Swp Cal adjust R60 U1034C and U1034D form a paraphase amplifier This stage converts the single ended input signal to a push pull output signal which is necessary ...

Page 49: ...NOTES ...

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