Keithley 775A User manual

All references to the 775 instrument in this manual apply to the 775A
©1985, Keithiey Instrumeiits, Inc.
Instrument Division
Cleveland, Ohio, U.S.A,

Keithiey Instruments, inc, warrants this product to be free from defects
in materia! and worf:<^3nship for a period of 1year from dais of ship-
ment. During th© warranty period, we will, at our option, either repair
or repiacs any product that proves to be defective.
To exercise this warranty, writ© or call your iocs! Keithley represent-
ative, or contact Keithley headquarters in Cievaiand, Ohio. You will be
given prompt assistance and return instructions. Send the instrument,
transportation prspaid, to the indicated service TadHty. Repairs will be
made and the instrument returned, transportation prepaid. Repaired
products are warranted for the balance cf the original warranty period,
or at least 90 days.
LIIVliTATlOW OF VmRBAiyTY
This warranty does not apply to defects resulting from unauthonzsd
modification or misuse of any product or part. This warranty also does
not apply to fuses, batteries, or damage from battery leakage.
This warranty is in lieu of ail other warranties, sxpre-ssed or implied, in-
ciuding sriy irnpiisd warranty of merchantability or fitness for apar-
ticular use. Keithley instruments., !nc. shall not be iiabieforany indirect,
speciai or consequential damages.
This instrument has been inspected and tested in sccordance with
specifications published by Keithley instruments, Inc.
The accuracy and calibration of this instrument are traceable to the
National Bureau of Standards through equipment which is calibrated at
planned Intervals by comparison to cenifiad standards maintained In
the Laboratories of Keithley instruments, inc,
KEITHLEY
KEITHLSV INSTRUMENTS. INC.
INSTRUHEHT DIVISION /28775 Aurora Road /Clevaiand, Ohio 44139 /U,S;A. /l2l6i 248-0400 /Telex: 98-5469
WEST agRMANYs K«lthlsy Instruments GmbH /Heiglhofstr, 5/8000 Munchen 70 /[phone] /Telex: 52-12160
aRE/.T BRITAIN: KeltNty Instruments, Ud. /1,Bouitor^ Road /Reading, Berkshire RG 2ONL/ (0734) 86-1 2-87/88 /Talex; 84-7047
FRANCE? Ksithisy Initrumente SARL /2, Bis Rue Ison Bium /B.P, 60/91121 Paiaiseau Cedex /(6) 011-51-55 /Telex; 600-933
NfTHEiRLANDS: Keithley Instruments BV /Arkeissdijk 4/Postbus 559 /4200 AN Go?'!nchem /(0) 1830-25577 /Telex: 24-684
SWITZERLAND: Keithley instruments SA /Krieabechstr, 4/8800 Dubendorf /01/821-S4-44 /Telex: 57-536
AUSTRIA: Keithley Instruments Gss.m.b.H, /Dobiinger Haupstr. 32 /1130 Wien /314 289 /Telex: 13-4500
ITALY; Kiithlsy Instruments, .SRL /Viale S. Gimignano 4/A /20100 Milarw, Italy /4120360

INPUT CHARACTERISTICS PERIOD A
Channel A, B; each channsi
RANGE.' 0to 12CMHz, dc coupled,
to 120MHZ; ac coupled.
SENSmVir/ (xl); 25mV nns, <10MHz,
50mV rm >10MHz.
DYNAMIC RANGE (xl): 50mV to 5V pk-pk, <20MHz.
i40mV to 2.5V pk-pk. >20MHz.
COUPLING: ac or dc, switchable.
IMPEDANCE: IMO nominaL, shuoted bj? <60pF,
ATTENUATOR: xl or xl0 nominal, switchable.
LX3W PASS FILTER: -lOdB at lOOkHz nominal, switchable.
SIGNAL OPERATING RANGE (xl>? -2,55V dc to -2,55V dc.
TRIGGER LEVEL: -2.55V dc to +2.55V dc, xl,
'25.5V dc to +25.5V dc, xlO,
TRIGGER LEVEL RESOLUTION! lOmV, ,xl,
lOOmV, xir.
TRIGGER LEVEL SHTHNC ACCURAO-!
±(35mV +2% of setting), xl,
±(350mV f2% of setting), xli)
TRIGGER LEVEL SETONG--OUTPUT: via rear panel BNC,
not adjusted for attenuators.
•SLOPE: +or -slope, switehable.
DAMAGE LEVEL:
xl: .dc=2kHz 25CfV dc 4- peak ac
2kHz-’i00kHz 5x10^' rms^Hz/frequencv
>100kHz 5V rms •
xJD: dc-20kHz
20kHz'100kHi
>10QkHz
250V dc -f peak ac
5X10"V rryi3®Hz,''irequency
50V' rms
R/VNGEi 10ns to 10" seconds.
LSD DISPLAYED: 10ns to 0.1ms.
ACCURACY:
±1 LSD ±{Time .Base Error xPeriod) ±Trigger Error.
RANGE: 10ns to lOsec.
LSD DISPIAVSD: (10ns xPeriod),/Gate Time.
RESOLUTION:
,, ,(1.4 XTV^er Error -i- 2ns) xPeriod
±.t Lbu ±^—
Gate llirie
ACCURACY: ±Resolution ^(Time Base Error xPeriod)
NUMBER OF PERIODS AVERAGED: Gate Time/Period
RA.NGE: IGns to 10^ seconds.
LSD DISPLAYED: 10ns to 0.1ms.
ACCURACY: ±1 LSD ±(Time Base Error xTime interval;
±Trigger Error ±Trigger Tuning Error ±2ns.
PULSE WTETTH A(Positive or Negative)
RANGE: lOns to K)" seconds.
LSD DU5PL.AYED; 10ns to 0.1ms.
ACCURACY: ±1 LSD ±(Time Base Error xPulse Width)
tTrigger Error ±Trigger Timing Error +2n.'>,
TOTALIZE A
Channel C(with Model 7751 option)
RANGE: SOMHz to 1.3GHz.
SENSITIVITY: 15mV, 50MHz to l.OGHz:
25mV, 1.0GHz to 1.2GHz;
;^mV, 1.2GHz to 1.3GHz
DYNAMIC lU^NGE: 25mV rms to IV rms.
COUPLING: ac,
IMPEDANCE: 5CQ.
DAMAGE LEVEL:
dC'lOQkHz 15V dc -r peak ac
>100kHz 5V rms
FREQUENCY A, B
RANGE: O.lHz to OOMHz,
LSD DISPLAYED: (10ns xFrequency)/Cate Time
RESOLUTION:
1\SD ^Tri^er Error -r 2ns)x Frequency
G^e Time
ACCURACY:
iResoiution ±(Time Base Error xFrequency)
DIGITS DISPL.4YED: 8per second of Gate Time, minimum.
MOOES: Cunuiiative or .A gated by B
RANGE: 0to 10** -1
REPETITION RATE: 120MHz max.
LSD DISPLiWED: 1count up to 10*®--!, then 9most sigmd'
cant dig,its.
ACCURACY: *1 LSD
GATH/DELAY
INTERNAL GATE TIME; Variable from. lOO^ts to lOsec in 43
increments, or one period of the input, whichever is longer,
May be used in Frequency and Period Average
measurements.
EXTERNAL GATE TIME: Contmuou.sly variable horn. 100/is
to IDsec; or one period of the input, whichever is longer.
EXT’ERNAL GATE DELAY: 10/iS +one period, of the
input .signal, maximum.
INTERNAL DELAY TIME: Variable from lOtV to iOsec m45
increments. May be used in Period, Time Interval and Pulse
Width mea-surements.
EXTERNAL DELAY TIME; Continuously variable from 100,us
to >1 hour.
EXTERNAL GATE/DELAY INPUT: Positive TTL signal via
rear panel BNC.

FREQUENCY; IOMH2.
AGING RATE; s5 xW“^/niORth.
THMPERAruaS; ±5 xK>“"e 0® to 40®C ref 25*C.
TCXO {with ModgI 7732 option)
FREQUENCY: lOMHz
AGING RATE: <1 xlO-’/month,
1‘EMPERAXURB: ±1 x10-^ 0to 4(FC ref 25*C.
UNB VOIXAGE: <1 x10“^ for 10% change,
IEEE488 INTERFACE
MULTILINE COMMANDS; DCL, LLO, SDC, GET, GTL,
UNX UNI, SPE, SFD.
UNIUNE COMMANDS; IFC, MK EOl, SRQ, ATN.
iNTSmCE FUNCTIONS; SHI, AHl, T6, TEO, U, LEO, SRI,
PPO, DCl, on, CO, El.
PROGRAMMABLE PARAMETERS; All front panel corttrob
(except I^WER) phos Reading Rate, Data Format, Trigger,
SOI, Termiiiatot, Service Request, Seif Test, Display, Status,
READING SATES; one shot, normal fS/serond), fast
(2f;/second), or dump (I'W/seeond),
DISPLAY; Nine LhD digits with decimal point and exponent,
BENCH reading RATHS: One shot, or normal (3/seccnd).
ARMING (TRIGGER); Each channel is amied by it's ov/n
signal; or RESET button or EXT ARMING input when in one
shot (HOLD) mode.
ARMING DELAY: '^fis in Frequency and Period Average;
iDgs in Period, Hme Interval and Pulse Width.
EXTERNAL ARMING INPUT. Positive edge TTL signal via
rear panel BNC.
EXTERNAL TIME BASE INPUT: lOMHz TTL signal via rear
panel BNG
TIME BASE: OUT: 2V minimum @lOMHz, lOOfl output resis-
tance, via rear pane! BNC.
GATE: LED Indicator lights when gate is open.
WARMUP: 2hours to rated accuracy ar;d stability,
OPERATING TEMPEKAIXIHE: 0^ to 40"C, 0% to 80% relative
huuiidity.
STORAGE TEMPERATURE: -25'^ to 65^C.
POWER: 103-125V or 2Y3-250V (rear panel switch selected),
5O-6OH2,35VA max, 90-1'UTv avadabie.
DIMENSIONS, WEIGHT: 127mm high x215mm wide x
359mm deep (5"x 8*/(i"x
Net weight 3.5kg (8 lbs).
Speciticiuions subject to change without notice.

SECTION 1-GENERAi INFORMATION
1.1 INTRODUCTION M
1,2 MODEL 775 FEATURES 1-1
1,3 ,WARRANTY INFOI^vtATION l-l
1:4 MANUAL ADDENDA ,M
1.5 SAFETY SYMBOLS AND TERMS 11
J.-I
1.6 INSPECTION 1-2
1.7 USING THE MODEL 775 MANUAL 1-2
1,8 ACCESSORIES 1-2
SECnON 2-BASIC COUNTER/TIMER
2,1
2,2
2.2,1
2.2.2
2.2.3
2.2.4
2,3
2.3.1,
2.3,2
2„3,3
2.3.4
2.4
2.5
2.5.1
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
2.6.6
2.6.7
2.6.8
2.6,9
2.7
2.7.1
2.7.2
2.7.3
2.7.4
2.8
INTRODUCTION
FRONT PANEL FAMILlARlZATIOs\i
Controls
Terminals
Display and Indicators
Tilt Bail
REAR PANEL FAMILIARIZATION
Connectors and Terminals
Line Vbkage Selector Switch
IEEE-488 Address Switches
Line Fuse
POWER-UP PROCEDURE
DISPLAY MESSAGES
No Option Message
CONTROL SELECTION
Function
Selecting Gate Time
User Gate Function
Using Delay
User Delay Function
Selecting Measurement Rate
Selecting the Number of Displayed Digits
Input Condition Controls Setting
Setting Trigger Levels
ARMING .
Continuous Arming
Front Panel Arming
External Arming
Alarm Conditions
APPLICATIONS
2-4
2-4
2-6
2-6
2-6
2-6
2-6
2-8
2-9
2-9
2-10
2-10
2-10
2-11
.Ml
2-12
2-1.2
2•12
2-13
2-13
2-13
ECTIOK 3-IEEE-488 OPERATION
3-1
O' i
3.1
3.2
INTRODUCTION ..
BUS DESCRIPTION

3,3 IEEE'488 BUS LINES
3, 3. ,IBus Management Lines
3.3.2 Handshake Lines -
3.3.3 Data Lines
3,4 BUS COMMANDS
3,4,1. Uniline Commands
3.4.2 Uruvetsal Commands
3.4.3 Addressed Commands
3.4.4 Unaddressed Commands
3.4.5 Device-Dependent Commands
3.5 COMMAND CODES
3.6 COMMAND SEQUENCE
3.6.1 Addressed Command Sequence
3,6, 2- Universal Command Sequence
3,6,3
Device-Dependent Command Sequence
3.7 HARDWARE CONSIDERATIONS
3.7.1 Typical Controlled Systems
3.7.2 Bus Connections
3.7.3 Primary Address Programming
3.8 SOFTWARE CONSIDERATIONS
.1,8.1 Controlled Interface Routines
3„8,2 HP-8 BASIC Statements
3.8.3 Interface Function Codes
.3.S.4 Model 775 Interface Commands
3.9 GENERAL BUS COMMAND PROGRAMMING
3.9.1 REN (Remote Enable)
3.9.2 IFC (Interface Clear)
3.9.3 LLO (Local Lockout)
3.9.4 GTL (Go To local)
3.9.5 DCL (Device Gear)
3.9.6 SDC (Selective Device Clear)
3.9.7 GET {'Group E.xecute Trigger)
3.9.8 Serial’ PoiUng (SPE, SPD)
3.;10 DEVICE-DEPENDENT COMM,AND PROGRAMMING
3, .10, !Execute (X)
1.10.2 Function (F)
3.10.3 Channels A, B Coupling (AC, 6C)
3. !04 Channels A, BAttenuator (AA., BA) .
3.10.5 Channels A, BFilter (.AF, BF)
3.10.6 Channels A, BSlope (AS, BS)
3.10 7Channels A, BTrigger Level (AL, BL)
:U0,B Rate (S) V
3.10.9 Gate Time (G)
3.10.10 Delay Time (W)
.3.10.11 Delay (1)
3.10.12 Displayed Digits (N)
Triggering (T)
3,10.14 EOl (K)
3.10.13 SRQ Mode (M) and Serial Poll Status Byte Format .
3,10.16 Displayed Modes (D)
.3,10,17 .Self-Test 0)
3.11 READING FROM THE MODEL 775
3,11,'i Data Control Commands (B)
.U1.2 Status Word (U)
3.
.
11. 3Terminator (Yi
.3.11.4 Prefix (P)
3.. .,5 Dump Mode (S3 Rate Mode)
..! ,.3-2
3-3
3-3
3-4
3-4
3-3
3-5
3-5
3-5
3-6
3-6
3-6
3-6
3-6
3-6
3-8
.... 3-10
3-'i0
... ,3-10
.... 3-11
...
,
3-12
...
.
3-13
.. .
.
3-13
.,,.3-13
., , .3-14
. . ,.3-14
, , ,.3-14
. . . , 3-15
.,..345
,,, , 3-15
.. . ,3-16
...,3-16
..,.3-19
, , , , 3-19
,,,,3-19'
, . . 3-20
.,.3-2U
.,.3-20
...3-20
.-.3-21
,,.3-22
..,3-22
... 3-23
.,.3-23
... 3-23
... 3-23
...3-24
...3-26
...3-27
.,.3-27
..,3-2.8
.,.3-29
... 3-30
... 3-31
,.,3-31

3-12
3.12.1
3.12.2
FRONT PANEL ,PROGRAIv&4!NG 3-34
IDDC Error.... 3-34
IDDCO Hrror 3-34
SECTION 4—PERPORMANCE VERIFICATION
4.1 INTRODUCnON 4-1
4.2 ENVIRONMENTAL CONDITIONS 4-1
4.3 RECOMMENDED TEST EQUIPMENT 4-1
4.4 INITIAL CONDITIONS 44
4.5 VERIFICATION PROCEDURES 44
4.5.1 Channels A, Band CInput Sensitivity 4-2
4.5.2 r^riod Measurement Accui'acy Check 4-2
4:5.3 Period Averaged Measurement Accuracy Check 4-2
4.5.4 Tune Interval A—BMeasurement Operation Check 4-2
4.5.5 Pulse AMeasiirement Operation Check 4-3
4.5.6 Delay Operation Check 4-3
4.5.7 ,External Gate Operation Check 4-3
4.5.8 Arming Operation Check 4-3
4.5.9 Model 7752 TCXO Accuracy Check 4-4
5—THEORY OF
5,1 INTRODUCTION 3-1
5.2 OVERALL FUNCnONAL F3ESCRIPTION ,,
.
3-1
^3ANALOG CIRCUITRY
5.3,1 Input Circuits Aand B
5.3,2 Input Circuit C
5.3.3 iOMHz Standard Reference Osdllator ,,,,
.
• . .,'‘"3
5.3,4 lOMHz TCXO Referertce Oscillator
53.5 '^
5.3.6 '' Measurement Section
5.3,7 Power Supply
5,4 DIGHAL CIRCUITRY ,.5-13
5,4.1 Microcomputer Block Diagram
5.4.2 Memory Mapping •'.1'
5,4,3 Address Decoding
5,4,4 K>yboard/0isplay Interface 5-M
5,4.5 IEEE Interface
SECTION 6-MAINTENANCE
6.1 INTRODUCTION 6T
6.2 LINE VOLTAGE SELECTION 6-1
6,3 FUSE REPLACEMENT 6-1
6,4 USING AN EXTERNAL TIME BASE 6-2
6,5 MODEL 7751 CHANNEL COFiTON INSTALLATION 6-3
6,6 MODEL 7752 TCXO OPTION INSTALLATION 6-4
6,7 CALIBRATION 6-5
6,7.1 Environmental Conditions 6-3
6,7,2 Warm-Up Period 6-.5
6,7.3 Recommended Thst Equipment -6-5
6,7.4 Calibration Procedure 6-5
6,75 Multiplier Adjustment -6-7

6.7.6 Adjustment
6.7.7 Channels Aand BSensitivity Adjustment
6,7,S Inputs Aand BAttenuator Compensation
6.79 Time Base Mjustment (Standard 5PPM Tune Base) ..
.
6,710 Time Base Adjustment (Optional 1PPM Time Base) ,,
.
6.8 SPECIAL HANDLING OF STATIC SENSITIVE DEVICES
6.9 DISASSEMBLY iNSTRUCHONS
6.10 TROUBLESHOOTING
6.10.1 Recommended Test Equipment
6.10.2 Power-Up Seif Diagnostics
6.10.3 Power Supply Checks
6.10.4 Reference Oscillator and Clock Checks
6, 10, .5 Digital Circuitry and Display Checks
6.10.6 Sigirai Coriditioning and Input Circuit Checks
6.10.7 Multiplier Circuit Checks
6.10.8 Trigger Level Checks
6.10.9 Measurement Section Checks
6-7
6-7
6-7
6-7
6-7
6-8
6-8
6-10
6-10
6-10
6-10
6-11
6-11
6-11
6-n
6-n
6-11
SECnON 7-^REPLACEABLE PART:
INTRODUCTION
PARTS LIST
ORDERING INFOILM^TION
RACTORY SERVICE
SCHEMATIC DLA.GRAM A.ND COMPONENT IDCAJION DRAWING!
APPENDIX
INDEX
7.1
7.2
7-3
7.4
7.5
7-1
7-1
7-1
7-1
7-1
-A-1
14
V

24 Mode! 775 Front Panel 2-2
2-2 Model 775 Rear Panel 2•^3
2-3 Fall Tinie Measurement 2-14
2-4 Using Delay to Measure Contact Dwell Time 2-!5
2-5 High Frequency Multiplexed Measurements 2-15
34
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
IEEE Bus Configuration
IFXE Handshake Sequence
Command Codes
System Types
IEEE-4^ Connector
IEEE-4!^ Connections
Rear Panel of Model 775 Showing IEEE connector
Contact Assignments
Typical IEEE»488 Bus Driver (One of 16)
IEEE-488 Display Error Messages , ,
,
3-2.
3-3
3-7
3-8
3-8
,3-9
3-9
3-9
340
3-33
54 Model 775 Simplified Block Diagram 3-2
5-2 Frequency AMeasurement Block Diagram :5-6
5-3 Frequency BMeasurement Block Diagram 5-7
5-4 Frequenc)'- CMeasurement Block Diagram ,:5-S
5-5 Period AMeasurement Block Diagram 5-9
5-6 rtme Intan-^l A-*B Measurement Block Diagram 5-10
5-7 Pulse Width Measurement Block Diagram. :3-H
5-8 Microcomputer Block Diagram 5-12
64 Model 775 -Standard 5ppm Tirrsebase d-2
6-2 Model 7751 Installation .6-3
6-3 Model 7752 Installation 6-4
6-4 Model 775 Calibration Adjustments 6-o
6-
5Model 775 Exploded View 6-9
74 Mother Board, Component Location Drawing /-ll
7-
2Mother Board, Schematic Diagram 7-.i3
7-3 Display Board, Component Location Drawing 7-26
7-4 Display Board, Schematic Diagram . . ..7-27
7-5 Model 7751, Component location Drawing 7-29
7-6 -Model 7751, Schematic Diagram 7-30
7-7 Model 7752, Component Location Drawing 7-31
7-8 Model 7752, Schematic Diagram 7-32
7-9 5ppm Oscillator, Component location Drawing 7-33
740 5ppm Oscillator, Schematic Location Diagram 7-34
V

i
2-1 Gate/Delay Deterinmatioii 2-8
2-
2Alarm Condition 2-13
3-
1rEEE-488 Bus Command Summary 3-4
3-2 Hexadecimal and Decimal Command Codes ri-Ci
3-3 Typical Addressed Command Sequence 3-ft
3-4 Typical Device-Dependent Command Sequence 3-6
3-5 fEEE Contact Designations 3-9
3-6 HP-85 IEEE-488 BASIC Statements 3-11
3-7 Model 775 Interface Function Codes 3-12
3-8 IEEE Command Groups 3-13
3-9 General Bus Commands ^-13
3-10 Default Conditions {Status Upon Power Up or After SDC or DCL) 3-15
3-n Device-Dependent Commar\d Summary 3-I7
3-12 Rate Commands 3-21
3-J3 Gate/Delay Time Predetermined Value 3-23
3-14 SRQ Mask Commands 3-24
3-15 SRQ Mask Legal Commands 3-25
,3-lb Status Byte Interpretation 3-26
3-L7 Data String Format 3-28
3-18 Prefixes .3-29
3-19 Status Vvbrd Format 3-30
3-20 Dump Mode Specifications. ,*3-33
3-21 Dump Ouput Mode Result Calculation 3-34
4-
1Recommended Test Equipment for Performance Verification
5-
1Model 775 Memory Mapping
6T Line Fuse Selection 6-1
b-2 Recommended Test Equipment tor Calibration 6-5
6-3 Static Sensitive Device 6-8
6-4 Recommended Minimum Test Equipment for Troubleshooting 6-!0
6-5 Power Supply Checks 6-11
6-6 Reference Oscillator and Clock Checks 6-12
6-7 Digital Circu'itr/ and Display Checks 6-12
6-8 Signal Conditioning Checks 6-1.3
6-9 input Circuit Checks 6-13
6-1.0 Multiplier Circuit Checks 6-1,3
6-
11 Trigger Level Circuit Checks 6-14
0-12 Measuring Section Circuit Checks 6-14
7'1 Mother Board, Parts List 7-2
7
-
2Display Board, Parts List 7-25
7-3 Mode) 775 Mechanical Parts List 7-3.5