Stanford Research Systems SR620 Manual
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Stanford Research Systems SR620 Manual

Universal time interval counter
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MODEL SR620
Universal Time Interval Counter
1290-D Reamwood Avenue
Sunnyvale, California 94089
Phone: (408) 744-9040 • Fax: (408) 744-9049
email: info@thinkSRS.com • www.thinkSRS.com
Copyright © 1989 by SRS, Inc.
All Rights Reserved.
Revision 2.5 (4/2004)

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  • Page 1 MODEL SR620 Universal Time Interval Counter 1290-D Reamwood Avenue Sunnyvale, California 94089 Phone: (408) 744-9040 • Fax: (408) 744-9049 email: info@thinkSRS.com • www.thinkSRS.com Copyright © 1989 by SRS, Inc. All Rights Reserved. Revision 2.5 (4/2004)
  • Page 2 SR620 Universal Time Interval Counter...

  • Page 3: Table Of Contents

    Scanning the D/A's External Trigger Delays TIME Mode Scan Examples Time Interval Arming Specification Guide +TIME +TIME, EXT Definition of Terms +TIME, EXT with HOLDOFF Least Significant Digit +/-TIME Resolution +/-TIME, EXT Error Differential Non-linearity SR620 Universal Time Interval Counter...
  • Page 4 Scope Display CAL Error Messages Counter Input Ports Common Operational Problems Display Control Ports Error Messages Front-End Status Bits Error Indicators ADC and DAC Control Bits Wrong Value REF OUT Excessive Jitter Delay and Gate Generator SR620 Universal Time Interval Counter...
  • Page 5 Fast Time Interval Logic 10/16 Time Interpolators 11/16 A/D, D/A and Threshold pots 12/16 Unregulated Power Supplies 13/16 Power Supply Regulators 14/16 Spares and Decoupling 15/16 Front Panel Display PCB 16/16 Component Placement on PCB SR620 Universal Time Interval Counter...
  • Page 6 Table of Contents SR620 Universal Time Interval Counter...
  • Page 7 Amp fuse and for 220V/240V, use a 1/2 Amp fuse. LINE VOLTAGE SELECTION LINE CORD The SR620 operates from a 100V, 120V, 220V, or The SR620 has a detachable, three-wire power 240V nominal ac power source having a line cord for connection to the power source and to a frequency of 50 or 60 Hz.
  • Page 8 Safety and Preparation for Use SR620 Universal Time Interval Counter...

  • Page 9: Specifications

    16 digit fixed point with LSD = 1 ps (1 fs with x1000 for periods ≤ 1 s) Display Phase Phase = 360 x (Tb - Ta) / Period A Range -180 to +180 degrees (0 to 100 MHz frequency) Resolution (25ps x frequency x 360 + 0.001) degree SR620 Universal Time Interval Counter...
  • Page 10 1 M Ohm Accuracy 0.3% of full scale Speed Formatted response in approximately 5 ms. D/A Outputs Two rear panel outputs which may be ramped Full Scale ±10.00 VDC Resolution 5 mV Impedance < 1 Ohm SR620 Universal Time Interval Counter...
  • Page 11 1400 binary responses per second. General Operating 0 to 50° C Power 100, 120, 220 or 240 VAC +5% -10%. 50/60 Hz. 70 Watts. Dimensions 14" x 14" x 3.5". Rack mounting hardware included. Weight 11 lbs SR620 Universal Time Interval Counter...
  • Page 12 Specifications SR620 Universal Time Interval Counter...

  • Page 13: Abridged Command List

    Sets the value of the frequency, period, of count gate to x. x may bebetween 1ms and 500s in a 1,2,5 sequence. If x < 0 a externally triggered gate of length x is set. JTTR(?) j Sets variance type to 0 = std dev, 1= Allan variance. SR620 Universal Time Interval Counter...
  • Page 14 Sets the autoprint mode to 0 = off or 1 = on. AUTS Autoscales the displayed graph. CURS (?) j Sets the cursor position to j. DGPH(?) j Sets the displayed graph to 0 = histogram,1= mean,2 = jitter GCLR Clears the displayed graph. SR620 Universal Time Interval Counter...
  • Page 15 STUP? Returns the complete setup in one string. Calibration Control (NOTE: these commands are not needed during normal operation) $TAC? j Reads the value of the time-to-amplitude converters. $PHK? j Sets the printer handshake lines. SR620 Universal Time Interval Counter...
  • Page 16 $POT? j Reads the value of trigger pot j *CAL? Starts autocal and returns status when done. *TST? Starts self-test and returns status when done. BYTE(?) j,k Reads/sets linearization byte values. WORD(?) j,k Reads/sets cal words. SR620 Universal Time Interval Counter...

  • Page 17: Quick Start Instructions

    Now select JITTER and press AUTO to more consistent MEAN value. display a 'strip-chart' of standard deviations for the scope display. 5) Press the SET key in the DISPLAY section to set the REL offset to the current value of the SR620 Universal Time Interval Counter...

  • Page 18: Instrument Overview

    0.01 s, 0.1 s, 1 s, Externally triggered fixed gates, External gates, Externally triggered The SR620 Time Interval Counter can do a variety adjustable gates from 1 us to 10 ms. Gates which of time interval and frequency measurements. The...

  • Page 19: Front Panel Operation

    The SR620 is different than most counters in that a "measurement" consists of from 1 to 1,000,000 "samples" and the SR620 reports statistical information on these samples. The SR620 can report the mean , jitter, maximum , and minimum values found in a measurement.

  • Page 20: Arming Mode Summary

    * arming delay or scanning delay/gate may be used in this mode (see CONFIGURATION MENU and ARMING sections). The EXT LED will flash if scanning is enabled. ** the gate time LED will flash if gate width multiplier is not equal to 1 (see CONFIGURATION MENU and ARMING sections). SR620 Universal Time Interval Counter...

  • Page 21: Choosing The Output Display

    "CLR" button. Normally the REL is about the measurement of N samples. set to the value of the mean when the "SET" SR620 computes and reports the mean, standard button is pressed. However, the REL may be set deviation or root Allan variance, minimum, and to an arbitrary value using the ZOOM feature maximum values seen during the measurement.

  • Page 22: Graphics Outputs

    (200,000 / div) will change GRAPHICS OUTPUTS the vertical scale to a log scale. To view the In addition to the 16 digit LED display the SR620's scales on the LED display press the "DISP" button.

  • Page 23: Hardcopy Output

    This is to avoid corrupting In addition to the scope outputs the SR620 also the second copy as the SR620 only has a 1 deep has two rear panel analog outputs designed to go graphics output queue.The output device (printer to analog chart recorders.

  • Page 24: Front-End Input Comparators

    67 was 1.635 kHz below the REL. Sample jitter stripchart. This graph shows the jitter associated with each measurement above. The vertical scale is 10 Hz/div. The cursor is at measurement number 165 and the jitter value there is 32.6 Hz. SR620 Universal Time Interval Counter...

  • Page 25: Setting The Inputs

    EXT input is being used to supply a gate pulse In all cases the trigger level resolution is 10mV the SR620 will use the time above threshold as and the actual level may be displayed on the front the gate if POSitive logic is selected and the time panel.

  • Page 26: Input Coupling

    DVM inputs. REFERENCE OUTPUT These 1 MOhm differential inputs allow the SR620 to measure DC voltages on either a 2V or The front panel REF output puts out a 1kHz 50% 20V full scale range. The SR620 can either duty cycle square wave synchronized to the autorange the inputs (default) or they may be set SR620's internal 10MHz clock.

  • Page 27: Sample Arming

    Start and a Stop pulse. The time is not armed. The ARM LED will turn on when the unit is armed. The SR620 remains busy for about interval is a positive number if the Start occurs before the Stop and negative if the Stop occurs 800us after receiving a Start/Stop pair and may not be rearmed during this time.

  • Page 28: Time, Ext

    For periodic inputs there is no way for the scanned via the CONFIG Menu. instrument to know if the desired time interval should be measured from the Start to the previous Stop or to the next Stop. For example, if the Start SR620 Universal Time Interval Counter...

  • Page 29: Width Arming

    T actual = sqrt ( T measured 2 - 1.2 ns 2 ) As transition times are always positive numbers, only +TIME and +TIME_EXT arming modes are allowed. SR620 Universal Time Interval Counter...

  • Page 30: Frequency Arming

    The frequency of either the A or B inputs may be accuracy, while for long gates the accuracy is measured in this mode of operation. The SR620 is limited by the accuracy of the timebase. a "reciprocal" frequency counter. That is, it...

  • Page 31: Count Arming

    B. The result, 360 x (250us/1000us) = +90.0000 In addition to the externally triggered arming degrees, would be reported to the LED display. modes discussed previously, the SR620 has a Phase readings are always displayed between - method of delayed external arming in which a user 180 and +180 degrees.
  • Page 32 (not the width of the external trigger pulse!). The SR620 has the ability to automatically scan the trigger delay after each measurement. This is discussed in the "SCANNING" section of the "CONFIGURATION MENU"...

  • Page 33: Configuration Menus

    19.2k baud. If the RS-232 echo is enabled, every character sent to the SR620 will be echoed back The "Autocal" procedure is used to null insertion to the sender. Use this only when using the SR620 delay differences between the start and stop SR620 Universal Time Interval Counter...

  • Page 34: Clock Source

    Select Printer or Plotter running. for hardcopy. Plot Port rS232 Specify RS-232 or GPIB To run Autocal, allow the SR620 to warm up for at for plotter port. least 1/2 hour, press the START button in the PlottEr Addr 5 Specify plotter’s GPIB SAMPLE SIZE section.

  • Page 35: Jitter Type Selection

    Scans may be turned "oFF" or set to level range over the communications interfaces. "SingLE" or "rEPEAt". In the "single" setting the the SR620 will take one scan and stop. In the SCAN MENU (Scn) "repeat" mode the SR620 will automatically reset...

  • Page 36: Setting D/A Outputs

    The step size taken by each D/A may be programmed in the next line of this menu. The First, set the SR620 to measure FREQuency of step size may be adjusted to any value from -10 to the A input with a 0.01 s gate. Select a SAMPLE +10 volts with 5 mV resolution.
  • Page 37 A input. It is important to select an EXTernal gate in the GATE/ARM section. The Note: If the VCO stops running, then the SR620 EXT LED will blink when the Delay Scan is will stop taking data, and everything stops. Clearly, enabled in the CONFIG menu.
  • Page 38 Then press the "RESET" key in the SAMPLE SIZE Press the "SEL" key to select the "Scn" menu. section to exit from the CONFIG menus.The Press the "SET" key and use the SCOPE AND SR620 will compose a scope display showing the CHART up/down keys...

  • Page 39: Specification Guide

    First a little terminology- TERMINOLOGY LEAST SIGNIFICANT DIGIT (LSD) The LSD is the smallest displayed increment in a measurement. The SR620 has a 4ps single-shot LSD and thus the smallest amount that two single-shot time interval measurements may differ by is 4ps. RESOLUTION Resolution is the smallest difference in a measurement that the SR620 can discern.

  • Page 40: Timebase Specifications

    TIMEBASE SPECIFICATIONS The specifications of the timebase affect both the resolution and error of measurements made with the SR620. A timebase may be specified by two parameters: its short-term stability and its long-term stability. SHORT-TERM STABILITY The short-term stability of an oscillator is a measure of the changes in the output frequency of the oscillator on a short time scale- seconds or less.

  • Page 41: External Timebases

    For shorter measurement times the clock characteristics are unimportant compared to the internal jitter (25ps rms) of the SR620. Thus, if the signal from a Cesium clock is input into a SR620 with a standard TCXO oscillator the short-term and long-term stability of the SR620 will become that of the Cesium clock.

  • Page 42: Measurement Accuracy

    MEASUREMENT ACCURACY The following equations allow one to calculate the SR620's resolution and error in the various measurement modes. The SR620's typical specification are used in the following equations. For worst case bounds simply replace the typical with the worst case numbers.
  • Page 43 × frequency gate time The SR620's typical single-shot frequency resolution as a function of gate time is shown in Graph 5. The curves are for the standard oscillator, the optional oven oscillator, and an external high stability reference. The input signal noise is negligible.
  • Page 44 Error = ± resolution ± × 360° − 8 timebase error × period ± 1 × 10 × period Graph 6 shows the SR620's single-shot phase resolution as a function of frequency. The resolution may be increased by averaging. Graph Single-Shot phase resolution frequency.

  • Page 45: Programming The Sr620

    The REM The SR620 supports the IEEE-488.1 (1978) LED is lit whenever the SR620 is in a remote state interface standard. It also supports the required (front panel locked out).

  • Page 46: Detailed Command List

    If the mark? in parentheses (?) after the mnemonic. buffer fills up the SR620 will hold off handshaking Commands that may ONLY be queried have a ? on the GPIB and attempt to hold off handshaking after the mnemonic.

  • Page 47: Measurement Control

    ), or is the The ARMM command selects the SR620's arming SR620 is in holdoff at the end of a scan point. mode. The parameter j sets the mode according to the following table. The measurement modes in...

  • Page 48: Data Transmission

    Note: after setting the SR620's mode the other it is done, not a new measurement. It is measurement parameters should be set to their...

  • Page 49: Binary Dump

    16 digits of precision. If the rel is set the BDMP j number returned is the REL'D value. The BDMP command puts the SR620 into its high- speed binary dump mode. j specifies the number XREL(?) x of points to be dumped and may range from 1 to 65535.

  • Page 50: Scan Control

    Programming Commands Once in binary dump mode the SR620 will take DBEG (?) j data and send it to the controller as fast as it can. Binary dump mode is terminated when: the count The DBEG command sets the start position of the expires, the front panel reset key is pressed, or internal delay scan.

  • Page 51: Graphics Control

    The SCEN command controls the enable status of the SR620's scanning features. If j = 0 scanning is disabled. If j = 1 the scan mode is set to SINGLE. Graphics Control Commands In this mode the unit will automatically stop taking data when a scan is complete.

  • Page 52: Front Panel Control

    B slope The PLOT command starts a plot or print. B ac/dc B termination PCLR ref level set auto measure The PCLR command clears any plots or prints in set autoprint progress. clear automeasure clear autoprint SR620 Universal Time Interval Counter...

  • Page 53: Interface Control

    The EXPD command sets the x1000 expand mode in frequency and period mode. The *RST common command resets the SR620 to parameter j = 1 turns expand ON while j = 0 turns its default configurations. It is the same as holding expand OFF.
  • Page 54 ENDT 13,69. STUP? The STUP? query returns the complete setup of the SR620 as a long string of numbers separated by commas. All setup information except for trigger levels and d/a starting and step voltages is returned. The meanings of the returned numbers are as follows: (when bits are packed into a status byte the bit values correspond to those used by the normal mode setting command.

  • Page 55: Status Reporting

    The LOCL command sets the RS232 local/remote function. If j = 0 the SR620 is local, if j = 1 the *SRE (?) j SR620 will go remote, and if j = 2 the SR620 will go into local lockout state.

  • Page 56: Serial Poll Status Byte

    On power on the SR620 may either clear all of its 19-23 stop tac errors same as start value n - 16 status enable registers or maintain them in the state they were in on power down.

  • Page 57: Event Status Byte

    A trig Set when the A channel trigger comparator switches B trig Set when the B channel trigger comparator switches Set when the SR620 becomes armed Ext Ovld Set by Ext input overload condition SR620 Universal Time Interval Counter...
  • Page 58 Programming Commands SR620 Universal Time Interval Counter...

  • Page 59: Programming Examples

    ASCII RESPONSES +250us So, when measuring short time intervals with graphs on and not in the binary dump mode, the SR620 has a throughput of about 1000 samples per second. There is some additional time required at the end of each group of measurements. This calculation time is zero ( no graphic displays, binary responses) or 5 ms ( no graphic displays, ASCII responses) or 8 ms (active chart outputs or scope display of mean or jitter) to 50 ms (scope display of histogram).
  • Page 60 "Control" CONFIG menu. The default GPIB address is 16: use this address unless a conflict occurs with other instruments in your system. The SR620 will be set to GPIB address 16 whenever a COLD BOOT is done ( if the RESET key is held down when the unit is turned "ON".) Make sure that you follow all the instructions for installing the GPIB card.

  • Page 61: Fortran/National Instruments

    Program Example 2 IBM PC, Microsoft FORTRAN V4.0, National Instruments GPIB Card This example demonstartes using the SR620 via the GPIB. Microsoft's FORTRAN (for PC compatibles) is used to program the time interval counter via National Instrument's GPIB interface card.

  • Page 62: Basic/Gpib/Binary Dump

    ' TIC command 390 ' 400 ' dma data into PC 410 CALL SEND (SR620%,C$,STATUS%) : GOSUB 890 ; SEND COMMAND 420 CALL TRANSMIT (TALK$,STATUS%) :GOSUB 890 ; MAKE TIC A TALKER 430 OFS%=VARPTR(DAT%(1)) 440 CALL DMA2 (SEGMENT%,OFS%,COUNT%,MODE%,STATUS%): GOSUB 890...
  • Page 63 Programming Examples 490 CALL ENTER (ANS$,LENGTH%,SR620%,STATUS%): GOSUB 890 'get answer 500 TMODE% = VAL (ANS$) ' TIC mode 510 CALL SEND (SR620%,EXPD$,STATUS%): GOSUB 890 520 ANS$ = SPACE$(50) 530 CALL ENTER (ANS$,LENGTH%,SR620%,STATUS%): GOSUB 890 540 TEXPD% = VAL(ANS$) 550 '...

  • Page 64: Fortran/Gpib/Binary Dump

    C set mode for DMA input mode = 16#2105 count = 8*samples address = 16 C set up TIC command(1:30) =' write (command,100)samples format ('BDMP',I4) call TxGpib (address,command) call TalkGpib (address) seg = -1 C read data via dma SR620 Universal Time Interval Counter...
  • Page 65 (words(j) .lt. 0)words(j) = 65536+words(j) continue C if answer less than 0 change sign and get magnitude if (data(4*i+3) .lt. 0) then sign = 1 do 12 j = 0,3 C take 1's complement of number SR620 Universal Time Interval Counter...
  • Page 66 C transmit command to address subroutine TxGpib (address,command) character*30 command character*70 tstring character*2 temp integer*2 status,address tstring (1:19) ='UNT UNL MTA LISTEN ' write (temp,100)address format (I2) C set up CEC command string tstring (20:21) = temp SR620 Universal Time Interval Counter...
  • Page 67 RECEIVE (rstring,length,status) call StatCheck (address,status) return C ******************************************************************** C checks gpib status and prints error message subroutine StatCheck (address,status) integer*2 address,status if (status .ne. 0) then write (*,*)'Error at device ',address,' status= ',status endif return SR620 Universal Time Interval Counter...

  • Page 68: C/Gpib/Binary Dump

    () char cmd[40],input[40]; int i,samples,seg,tmode,texpd; static char *units[] ={"s","s","s","Hz","s","deg","ct"}; InitGpib (); /* initialize controller */ while (1) /* read number of samples */ printf ("Enter number of samples (<cr> to quit) ->"); gets (input); SR620 Universal Time Interval Counter...
  • Page 69 = 8*samples; /* number of bytes */ /* set up TIC */ sprintf (cmd,"BDMP%d",samples); /* set binary dump mode of n samples */ TxGpib (sr620,cmd); /* send command to TIC */ TalkGpib (sr620); /* make TIC a talker */ dma2 (&status,&mode,&count,data,&seg);...
  • Page 70 /* ********************************************************************* */ void TxGpib (address,command) /* transmit command to address */ int address; char *command; char t_string[150]; int result; result = sprintf (t_string,"UNT UNL MTA LISTEN %d DATA '%s' END", address,command); transmit (&status, t_string); StatCheck (address); SR620 Universal Time Interval Counter...
  • Page 71 (recv, temp); /* ******************************************************************** */ void StatCheck (address) /* check the gpib status and exit if error */ int address; if (status != 0) printf ("Error at device %d : status = %d",address,status); exit (0); SR620 Universal Time Interval Counter...
  • Page 72 Programming Examples SR620 Universal Time Interval Counter...

  • Page 73: Troubleshooting Tips

    (See below) Other cAL Errors flag hardware problems per the table below: If the message "code error" appears it indicates that the SR620's ROM has an error and the unit Cal Error Problem should be sent back for repair.

  • Page 74: Error Indicators

    SOURCE, select positive slope for START and the GPIB address. STOP, and set B's threshold pot for AUTOLEVEL.) The SR620 will ignore its front panel key pad EXCESSIVE JITTER when Remote Enable (REN) has been asserted by the GPIB. This "REMOTE" state is indicated by the The most common causes of excess jitter are (1) REM LED in the STATUS section.

  • Page 75: Interface Problems

    "ctrL" section of the CONFIG menu. The 5) Answers are coming back from the SR620 to SR620 always sends two stop bits, and will fast, overwriting previous responses before correctly receive data sent with either one or two stop bits.
  • Page 76 Troubleshooting Tips SR620 Universal Time Interval Counter...

  • Page 77: Performance Tests

    The MODE down arrow key will step backward through the specifications in the front of this manual. The first set of tests test the functionality of the SR620 from pattern. the front panel and verify the functionality of the circuitry. The second set of tests actually measure 3) Push the up arrow key again and all of the segments of all 16 digits should light.

  • Page 78: Counter Channel Tests

    Counter Channel Tests 1) Set the REF output to TTL and connect it to the EXT input. 1) Set the SR620 to TIME mode, A source, +TIME arming, sample size to to 500, 2) Adjust the EXT trigger knob and verify the...

  • Page 79: Performance Tests

    10MHz. These tests confirm that the A and B inputs and UHF prescalers have normal sensitivity. 1) Allow the SR620 to warm up for at least 1/2 hour. 1) Attach the function generator's reference clock 2) Set the SR620 mode to frequency, source to input to the SR620's 10MHz output.

  • Page 80: Trigger Accuracy

    These tests verify the accuracy of the rear panel Record the results. D/A outputs. 8) Set the SR620's A input to UHF. Set the A specification: 0.3% full scale (±30mV) trigger level to 0.00V.Set the generator 300MHz with a -22dBm output level. Measure 1) Connect the voltmeter to the D/A 0 output.
  • Page 81 Performance Test 5) Set D/A output #0 to 10.00 V. Compare the SR620 reading to that of the voltmeter. The difference should be < 60mV. Record the difference. 6) Repeat steps 1-5 for DVM input 1. Record the results. THIS COMPLETES THE PERFORMANCE...
  • Page 82 Performance Test SR620 Universal Time Interval Counter...

  • Page 83: Test Scorecard

    9.999999 MHz _________ 10.000001 MHz 100 MHz 99.99999 MHz _________ 100.00001 MHz 300 MHz 299.99997 MHz _________ 300.00003 MHz A UHF 300 MHz 299.99997 MHz _________ 300.00003 MHz 1.3 GHz 1.29999987 GHz _________ 1.30000013 GHz SR620 Universal Time Interval Counter...
  • Page 84 DVM #0 10.0 V _________ ∆ = -0.006V ∆ = 0.006V DVM #1 0.0V _________ ∆ = -0.006V ∆ = 0.006V DVM #1 1.8 V _________ ∆ = -0.06V ∆ = 0.06V DVM #1 10.0 V _________ SR620 Universal Time Interval Counter...

  • Page 85: Calibration

    = base (byte40)+correction) adjusted) by putting the "cal enable" jumper for inputs and slopes A+B+,A+B-,A- (inside the SR620 at the front center of the circuit B+,A-B-,REF+B+,REF+B-,REF-B+, board) into the "enable" position and then looking REF-B-,B+A+,B-A+,B+A-,B-A- at the "Caldat" line in the Cal submenu.

  • Page 86: Simple Calibration

    2) Adjust C402 (C422,C442) for best pulse frequency is correct. shape on the 10 us/div scope display. Note: Attach a x-y scope to the SR620 and look at Input Threshold Offset Calibration the histogram display. The mean value can be...

  • Page 87: Clock Oscillator Calibration

    4096. If the frequency of the oven 11) Attach the non-inverting output of the power oscillator cannot be set with a calbyte in this splitter to A and the inverting output to B. range, set the calbyte to midrange (2048) and SR620 Universal Time Interval Counter...

  • Page 88: D/A Output Calibration

    4) Adjust calbyte 17 until the meter reads within 5 mV of 0. 1) Set the mode to width, arming to +time. Set both A and B thresholds to the midpoint of the D/A Output Gain Calibration: input signal. SR620 Universal Time Interval Counter...

  • Page 89: Dvm Input Calibration

    9) Set the dc source for about 1.8V. 10) Adjust calbyte 26 until the DVM 0 reading and the voltmeter agree. 11) Repeat 1-10 for DVM input 1 to get values for calbytes 21,25,23, and 27. SR620 Universal Time Interval Counter...
  • Page 90 74 Calibration Procedure SR620 Universal Time Interval Counter...

  • Page 91: Circuit Description

    P2_3 -Gpib_Int IEEE-488 interface high. However, with this bit set low, the Z8800 can P2_4 -RTC 1 kHz real-time clock read data which is present at the printer port. SR620 Universal Time Interval Counter...

  • Page 92: Rs-232 Interface

    90 MHz timebase. It may also be used to count events when in the COUNT Mode. The SR620 is a DCE and may be connected to PC's using a standard serial cable (not a "null The seven LSB's from the CYCLE counter are modem"...

  • Page 93: Front-End Status Bits

    Low for dc couple on A 4 -B_dc Low for dc couple on B the mode of the ECL circuits which do the fast measurements. U237 and the LSB of U238 control 5 CMP1_A/-B Selects A or B for Comp1 SR620 Universal Time Interval Counter...

  • Page 94: Ref Out

    Q output of U244A will be output impedance which supplies 4V to high set high, releasing the clear to the divide-by-two impedance loads, 2V to 50 Ohm loads, and ECL (U241B). Cmp3 is the comparator output for the SR620 Universal Time Interval Counter...

  • Page 95: Timebase

    UHF prescaler allows frequency measurements the input to the four pole crystal filter. to 1.3 GHz. The crystal filter provides about 80 dB of selectivity for the 90 MHz signal, which is discriminated by U305, a fast ECL comparator. SR620 Universal Time Interval Counter...

  • Page 96: Trigger Multiplexers

    The comparator threshold gates or gates which are delayed or scanned is set by the output of U406A which serves as a relative to and external trigger. The rising edge of SR620 Universal Time Interval Counter...

  • Page 97: Event Gating

    A 4 V step at the source will launch a 2 V event counting: fixed gates from 1 us to 1 s, wave. The line, which has a characteristic delayed/scanning gates from an external trigger, impedance of about 100 Ohms, will provide a SR620 Universal Time Interval Counter...

  • Page 98: Fast Time Interval Logic

    90 start and stop latches high. Changing the Par/Hoff MHz clock ticks in the time interval. bit will allow the compliment period to be measured. U612A&B are preset by the "Load" pulse. SR620 Universal Time Interval Counter...

  • Page 99: Time Integrators

    A and B inputs. The circuit references U705A, on the polypropylene capacitor, C706. The will be given for the A input. SR620 Universal Time Interval Counter...

  • Page 100: Digital To Analog Converter

    +/- 7V supplies in order to reduce rectifier becomes a high resistance, and some portion of losses. the full 6 mA can be drawn from the base of Q907, which turns Q908. This proportional SR620 Universal Time Interval Counter...

  • Page 101: Power Supply Bypass

    The pn diodes in the strobe lines prevent simultaneous key closures in different columns from affecting the display refresh. SR620 Universal Time Interval Counter...
  • Page 102 86 Circuit Description SR620 Universal Time Interval Counter...

  • Page 103: Component Parts List

    D 41 3-00012-306 GREEN LED, Rectangular D 42 3-00884-306 LED, Rectangular D 43 3-00012-306 GREEN LED, Rectangular D 44 3-00012-306 GREEN LED, Rectangular D 45 3-00012-306 GREEN LED, Rectangular D 46 3-00012-306 GREEN LED, Rectangular SR620 Universal Time Interval Counter...
  • Page 104 SR620-19 Printed Circuit Board SW901 2-00023-218 DPDT Switch, Panel Mount, Power, Rocker SW902 0-00443-000 SWITCH Hardware, Misc. 3-00288-340 HDSP-H101 Integrated Circuit (Thru-hole Pkg) 3-00288-340 HDSP-H101 Integrated Circuit (Thru-hole Pkg) 3-00288-340 HDSP-H101 Integrated Circuit (Thru-hole Pkg) SR620 Universal Time Interval Counter...
  • Page 105 Capacitor, Ceramic Disc, 50V, 10%, SL C 104 5-00008-501 Capacitor, Ceramic Disc, 50V, 10%, SL C 105 5-00052-512 .01U Cap, Stacked Metal Film 50V 5% -40/+85c C 106 5-00021-501 Capacitor, Ceramic Disc, 50V, 10%, SL SR620 Universal Time Interval Counter...
  • Page 106 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 404 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 405 5-00002-501 100P Capacitor, Ceramic Disc, 50V, 10%, SL C 406 5-00062-513 .0022U Capacitor, Mylar/Poly, 50V, 5%, Rad SR620 Universal Time Interval Counter...
  • Page 107 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 703 5-00002-501 100P Capacitor, Ceramic Disc, 50V, 10%, SL C 704 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 705 5-00049-566 .001U Cap, Polyester Film 50V 5% -40/+85c Rad SR620 Universal Time Interval Counter...
  • Page 108 Capacitor, Tantalum, 35V, 20%, Rad C 910 5-00192-542 22U MIN Cap, Mini Electrolytic, 50V, 20% Radial C 911 5-00192-542 22U MIN Cap, Mini Electrolytic, 50V, 20% Radial C 912 5-00127-524 2.2U Capacitor, Tantalum, 50V, 20%, Rad SR620 Universal Time Interval Counter...
  • Page 109 C 994 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 995 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 996 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U C 997 5-00023-529 Cap, Monolythic Ceramic, 50V, 20%, Z5U SR620 Universal Time Interval Counter...
  • Page 110 D 303 3-00004-301 1N4148 Diode D 402 3-00203-301 1N5711 Diode D 403 3-00203-301 1N5711 Diode D 404 3-00403-301 1N459A Diode D 405 3-00403-301 1N459A Diode D 422 3-00203-301 1N5711 Diode D 423 3-00203-301 1N5711 Diode SR620 Universal Time Interval Counter...
  • Page 111 N 205 4-00468-420 300X8 Resistor Network, DIP, 1/4W,2%,8 Ind N 206 4-00551-420 12X8 Resistor Network, DIP, 1/4W,2%,8 Ind N 213 4-00266-421 4.7KX3 Res. Network, SIP, 1/4W,2% (Isolated) N 214 4-00291-421 10KX3 Res. Network, SIP, 1/4W,2% (Isolated) SR620 Universal Time Interval Counter...
  • Page 112 4-00284-421 1.0KX4 Res. Network, SIP, 1/4W,2% (Isolated) N 804 4-00220-420 10KX8 Resistor Network, DIP, 1/4W,2%,8 Ind 7-00700-701 TCXO BOARD Printed Circuit Board PC101 7-00173-701 SR620 Printed Circuit Board Q 101 3-00140-325 2N2369A Transistor, TO-92 Package SR620 Universal Time Interval Counter...
  • Page 113 Transistor, TO-92 Package Q 905 3-00258-329 TIP42 Voltage Reg., TO-220 (TAB) Package Q 906 3-00022-325 2N3906 Transistor, TO-92 Package Q 907 3-00022-325 2N3906 Transistor, TO-92 Package Q 908 3-00257-329 TIP41B Voltage Reg., TO-220 (TAB) Package SR620 Universal Time Interval Counter...
  • Page 114 Resistor, Carbon Film, 1/4W, 5% R 325A 4-00086-401 Resistor, Carbon Film, 1/4W, 5% R 326 4-00062-401 Resistor, Carbon Film, 1/4W, 5% R 327 4-00031-401 Resistor, Carbon Film, 1/4W, 5% R 328 4-00048-401 2.2K Resistor, Carbon Film, 1/4W, 5% SR620 Universal Time Interval Counter...
  • Page 115 Resistor, Metal Film, 1/8W, 1%, 50PPM R 425 4-00065-401 3.3K Resistor, Carbon Film, 1/4W, 5% R 426 4-00034-401 Resistor, Carbon Film, 1/4W, 5% R 427 4-00021-401 1.0K Resistor, Carbon Film, 1/4W, 5% R 428 4-00081-401 Resistor, Carbon Film, 1/4W, 5% SR620 Universal Time Interval Counter...
  • Page 116 Resistor, Carbon Film, 1/4W, 5% R 701 4-00080-401 Resistor, Carbon Film, 1/4W, 5% R 702 4-00041-401 Resistor, Carbon Film, 1/4W, 5% R 703 4-00090-401 Resistor, Carbon Film, 1/4W, 5% R 704 4-00080-401 Resistor, Carbon Film, 1/4W, 5% SR620 Universal Time Interval Counter...
  • Page 117 10.20K Resistor, Metal Film, 1/8W, 0.1%, 25ppm R 819 4-00432-407 56.2K Resistor, Metal Film, 1/8W, 1%, 50PPM R 821 4-00138-407 10.0K Resistor, Metal Film, 1/8W, 1%, 50PPM R 822 4-00057-401 Resistor, Carbon Film, 1/4W, 5% SR620 Universal Time Interval Counter...
  • Page 118 R 926 4-00185-407 4.02K Resistor, Metal Film, 1/8W, 1%, 50PPM R 931 4-00059-401 Resistor, Carbon Film, 1/4W, 5% R 932 4-00034-401 Resistor, Carbon Film, 1/4W, 5% R 933 4-00061-401 240K Resistor, Carbon Film, 1/4W, 5% SR620 Universal Time Interval Counter...
  • Page 119 Integrated Circuit (Thru-hole Pkg) U 130 3-00155-340 74HC04 Integrated Circuit (Thru-hole Pkg) U 131 3-00199-340 74HC4538 Integrated Circuit (Thru-hole Pkg) U 201 3-00044-340 74HC244 Integrated Circuit (Thru-hole Pkg) U 202 3-00044-340 74HC244 Integrated Circuit (Thru-hole Pkg) SR620 Universal Time Interval Counter...
  • Page 120 Integrated Circuit (Thru-hole Pkg) U 407 3-00143-340 LM393 Integrated Circuit (Thru-hole Pkg) U 408 3-00294-340 AD96685 Integrated Circuit (Thru-hole Pkg) U 410 3-00196-335 HS-212S-5 Relay U 412 3-00126-335 1A05 Relay U 413 3-00554-340 SP4633 Integrated Circuit (Thru-hole Pkg) SR620 Universal Time Interval Counter...
  • Page 121 Integrated Circuit (Thru-hole Pkg) U 808 3-00270-340 74HC4051 Integrated Circuit (Thru-hole Pkg) U 809 3-00088-340 LF353 Integrated Circuit (Thru-hole Pkg) U 810 3-00088-340 LF353 Integrated Circuit (Thru-hole Pkg) U 901 3-00143-340 LM393 Integrated Circuit (Thru-hole Pkg) SR620 Universal Time Interval Counter...
  • Page 122 554808-1 Hardware, Misc. 0-00514-030 TUBULAR NYLON Spacer 0-00520-048 18" #18 Wire, #18 UL1015 Strip 3/8 x 3/8 No Tin 0-00522-053 3-1/2" #24 Wire #24 UL1007 Strip 1/4x1/4 Tin 1-00066-112 7 PIN; 24AWG/WH Connector, Amp, MTA-100 SR620 Universal Time Interval Counter...
  • Page 123 0-00283-000 BUMPER1 Hardware, Misc. 0-00292-026 6-32X3/16 TRUSS Screw, Black, All Types 0-00315-021 6-32X7/16 PP Screw, Panhead Phillips 1-00087-131 2 PIN JUMPER Connector, Female 7-00169-720 SR620-39 Fabricated Part 7-00171-720 SR620-41 Fabricated Part 7-00172-720 SR620-42 Fabricated Part SR620 Universal Time Interval Counter...
  • Page 124 108 Parts List SR620 Universal Time Interval Counter...

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