Tektronix 492, 492P User manual

I
I T Z Z l f SERVICE
| 1 C l X MANUAL Part No. 070-3783-01
Produ t Group 26
I
I
1
1
I492/492P
ISPECTRUM
1ANALYZER
PORTABLE/RACKMOUNT/BENCHTOP
(SN B030000 & UP)
VOLUME
WARNING
THE FOLLOWING SERVICING INSTRUCTIONS
ARE FOR USE BY QUALIFIED PERSONNEL ONLY.
TO AVOID PERSONAL INJURY, DO NOT
PERFORM ANY SERVICING OTHER THAN THAT
CONTAINED IN OPERATING INSTRUCTIONS
UNLESS YOU ARE QUALIFIED TO DO SO. REFER
TO OPERATORS SAFETY SUMMARY AND
SERVICE SAFETY SUMMARY PRIOR TO
PERFORMING ANY SERVICE.
Please Check for CHANGE INFORMATION at the Rear of This Manual
First Printing FEB 98
Revised FEB 984 ■ - ■
Tfektronix
COMMITTED TO EXCELLENCE
J

492/492P Service Vol. I (SN B030000 & up)
TABLE OF CONTENTS
This anual is divided into two volu es as follows:
VOLUME 1
Page
LIST OF ILLUSTRATIONS...................................... vi
LIST OF TABLES................................................... ix
SERVICING SAFETY SUMMARY............................ x
Section 1 GENERAL INFORMATION AND
SPECIFICATION
GENERAL INFORMATION .................. 1-1
Introduction...................................... 1-1
Product Service.............................. 1-1
Instru ent Construction .................. 1-1
Elapsed Ti e Meter ........................ 1-2
Changing Power Input Range ........ 1-2
Replacing Fuses.............................. 1-2
Selected Co ponents .................... 1-2
Co ponent Circuit Nu bering
Sche e ........................................... 1-3
Fir ware Version and Error
Message Readout.......................... 1-3
Rack ount/Benchtop Versions .... 1-3
SPECIFICATION.............................. 1-4
Electrical Characteristics ............ 1-4
Frequency Related ................ 1-4
A plitude Related .................. 1-7
Input Signal Characteristics .. 1-10
Output Signal Characteristics. 1-10
General Characteristics .......... 1-11
Power Require ents .............. 1-11
Environ ental Characteristics... 1-12
Physical Characteristics .............. 1-13
ACCESSORIES.................................... 1-14
OPTIONS ........................................... 1-14
Option 0 1 ....................................... 1-14
Option 0 2 ....................................... 1-17
Option 0 3 ....................................... 1-17
Option 08 ....................................... 1-18
Option 2 0 ....................................... 1-18
Option 21 ....................................... 1-19
Option 22 ....................................... 1-19
Options 30, 31, 32 .......................... 1-19
Options for power cord
configurations.................................. 1 - 2 0
Page
Section 2 INSTALLATION AND REPACKAGING
Introduction ..................................... 2-1
Unpackaging and Initial Inspection. . 2-1
Preparation for Use........................ 2-1
Power Source and Power
Require ents.................................. 2-1
Repackaging for Ship ent .............. 2-2
Section 3 CALIBRATION
Introduction...................................... 3-1
History Infor ation.......................... 3-1
Equip ent Required........................ 3-1
PERFORMANCE CHECK
PROCEDURE...................................... 3-4
Introduction...................................... 3-4
Inco ing Inspection Test ................ 3-4
Verification of
Tolerance Values.............................. 3-4
Preli inary Preparation .................. 3-4
1. Check Operation of Front Panel
Push-buttons and Controls ........ 3-4
2. Check Frequency Readout
Accuracy for 492/492P and
Tune Accuracy for 492P Only .. . 3-7
2A. 492P Only—TUNE Accuracy
Check.......................................... 3-8
3. Check Calibrator........................ 3-10
4. Check RF Attenuator ................ 3-11
5. Check IF Gain Accuracy ............ 3-12
6. Check Display Accuracy and
Range ....................................... 3-14
7. A plitude Variation with Change
in Resolution Bandwidth ............ 3-14
8. Check Frequency Response .... 3-15
9. Check Preselector Ulti ate
Rejection.................................... 3-20
10. Check Frequency Span /Div
Accuracy.................................. 3-20
11. Check Ti e/Div Accuracy ........ 3-22
12. Check Pulse Stretcher .............. 3-23
REV AUG 1981 i

492/492P Service Vol. I (SN B030000 & up)
Section 3
TABLE OF CONTENTS (cont)
CALIBRATION (cont) Page Section 3 CALIBRATION (cont) Page
13. Check Resolution Bandwidth 16. Band Leveling for Coaxial Bands
and Shape Factor.................... 3-23 (Bands 1—5)............................ 3-71
14. Check Sensitivity ......................
3-24 17. Band Leveling for Waveguide
15. Frequency Drift........................ 3-26 Bands (Bands 6—11)
..............
3-72
16. Check Residual FM .................. 3-27 18. Preselector Driver (Option 01)
17. Check Inter odulation Calibration
...............................
3-73
Distortion .................................
3-28 19. Phaselock Calibration
.............. 3-76
18. Check Har onic Distortion .... 3-29
19. Check Noise Sidebands ..........
3-30
20. Check Residual Response .... 3-30
21. Check LO E ission Out the RF Section 4 MAINTENANCE
INPUT .....................................
3-31 Introduction
.....................................
4-1
22. Check Digital Storage Static-Sensitive Co ponents
..........
4-1
(Option 02) ...............................
3-31 PREVENTIVE MAINTENANCE
............
4-2
23. Check Triggering Operation Elapsed Ti e Meter........................ 4-2
and Sensitivity.......................... 3-31 Cleaning
.........................................
4-2
24. Check External Sweep Lubrication
.....................................
4-2
Operation ................................. 3-32 Service Fixtures and Tools for
25. Check Vertical Output ..............
3-34 Maintenance
...................................
4-2
26. Check Horizontal Signal Visual Inspection............................ 4-3
Output .....................................
3-34 Transistor and Integrated Circuit
27. 492P GPIB Verification Checks
...........................................
4-3
Progra ...................................
3-34 Perfor ance Checks and
DJUSTMENT PROCEDURE ............ 3-42 Recalibration
...................................
4-3
1. Check and Adjust Low Voltage TROUBLESHOOTING.......................... 4-3
Power Supply ............................ 3-43 Troubleshooting Aids...................... 4-3
2. Crt Display (Z-Axis & High Voltage General Troubleshooting
boards) .......................................
3-44 Techniques
.....................................
4-5
and frequency response) ............ 3-45 CORRECTIVE MAINTENANCE
..........
4-7
4. Adjust Sweep Ti ing ................
3-47 Obtaining Replace ent Parts
..........
4-/
5. Calibrate 1st LO Syste and Parts Repair and Return Progra . . A-l
Center Frequency Control .......... 3-50 Soldering Techniques...................... 4-7
6. Check 2nd LO Frequency and Replacing Square Pin for Multi-pin
Adjust Tuning Range ..................
3-53 Connectors...................................... 4-/
7. Adjust 1 st Converter Bias ..........
3-57 Selected Co ponents.................... 4-8
8. Baseline Leveling (Video Installing Matched Crystals for the
Processor) ................................. 3-58 VR 100 Hz Filters............................ 4-8
9. Log A plifier Calibration ............ 3-61 Replacing EPROM’s or ROM’s .... 4-8
10. Calibrating Resolution Band Fir ware Version and Error
width and Shape Factor ..........
3-63 Message Readout .......................... 4-8
11. Presetting Variable Resolution Servicing the VR Module
................
4-8
Gain and Band Leveling ..........
3-66 REPLACING ASSEMBLIES AND
12. Calibrator Output Level ............
3-68 SUBASSEMBLIES
.............................
4-10
13. IF Gain Calibration .................... 3-68 Re oving and Replacing Se i-rigid
14. Digital Storage Calibration .... 3-69 Coaxial Cables
...............................
4-10
15. Setting B —SAVE A Reference Replacing the Dual Diode Asse bly 4-10
Level .......................................
3-71 Replacing the C rt............................ 4-10
ii REV JUN 1983

*1
492/492P Service Vol. I (SN B030000 & up)
TABLE OF CONTENTS (cont)
Page Page
Sectio 4 MAINTENANCE (co t) Sectio 4 MAINTENANCE (co t)
Repairing the Crt Trace Rotation 7. Check and Calibrate
Coil .................................................
4-14 Tune Sensitivity.......................... 4-34
Front Panel Asse bly ....................
4-14 8. Conclusion
.................................
4-34
Front Panel Board.......................... 4-14 Troubleshooting Aids for the 2182 MHz
Replacing Front-Panel Push Button Phaselocked 2nd LO
...........................
4-35
Switches .........................................
4-15 MICROCOMPUTER SYSTEM
Main Power Supply Module ............
4-15 MAINTENANCE
.................................
4-36
High Voltage Power Supply ............
4-16 Me ory Board Option Switch
........
4-36
Replacing the 1st (YIG) Local Power-Up Self-Test Mode
..............
4-37
Oscillator Interface Board ................ 4-16 Microco puter Test Mode
..............
4-38
Co pliant Mounted Fan .................. 4-16 Instru ent Bus Check Mode
..........
4-39
MAINTENANCE ADJUSTMENTS 4-19 Fir ware Operating Notes
..............
4-39
110 MHz IF Asse bly Return Loss Exceptions for Fir ware
Calibration .......................................
4-19 Version 8 .2
.....................................
4-40
2072 MHz 2nd Converter ..........
4-19 Exceptions for Fir ware
Four Cavity Filter ........................
4-20 Versions 8.2, 8.7 and 8 . 8
................
4-41
M ixer .........................................
4-20 Exceptions for Fir ware
110 MHz Three Cavity Filter 4-20 Version 1.1 (492P only) .................. 4-41
829 MHz Converter Maintenance ........
4-21 Exceptions for Fir ware
1. To gain acceses to the LO Versions 1.1 and 1.2 in 492P only .. 4-42
section........................................ 4-21 Changes incorporated in
2. To gain access to the IF Version 1.2 Fir ware...................... 4-42
section .......................................
4-21 TROUBLESHOOTING ON THE
3. 719 MHz Oscillator Range INSTRUMENT BUS ............................ 4-42
Adjust ent ................................ 4-21 Instru ent Bus Data Transfers 4-42
4. 829 MHz Coaxial Bandpass Filter Instru ent Bus Registers
................
4-45
Adjust ent ................................ 4-22
Troubleshooting and Calibrating
the 2182 MHz Phaselocked 2nd LO ... 4-25
Oscillator Section ................................ 4-27
1. Preparation ................................ 4-27 Sectio 5 THEORY OF OPERATION
2. Adjust and Check Functional and General Description ... 5-1
Oscillator Frequency ..................
4-27 Detailed Description 5-3
3. Measure Output Power ..............
4-28 1 st Converter
.................................
5-3
4. Check the 2200 MHz RF Interface Circuits
..................
5-4
Reference Mixer ........................
4-29 RF Circuitry
...............................
5-5
5. Check Tune Range ....................
4-29 2nd Converter
................................. 5-6
6. Reasse bly................................ 4-29 2072 MHz 2nd Converter
.......... 5-8
Troubleshooting and Calibrating 2182 MHz Phaselocked
the 14-22 MHz Phaselock Section 2nd LO
.......................................
5-10
of the 2nd LO Asse bly ......................
4-30 General Description
................ 5-10
1. Preli inary.................................. 4-31 2182 MHz Microstrip
2. Check Voltages.......................... 4-31 Oscillator
............................... 5-10
3. Check Tune Linearity ..................
4-31 2200 MHz Reference Board .. 5-11
4. Coarse Linearity Adjust ent.... 4-32 2200 MHz Reference Mixer .. 5-11
5. Fine Linearity Adjust ent ..........
4-33 14-22 MHz Phaselock Board . 5-11
6. Set the Center Frequency Cavity 2nd LO Local Oscillator.. 5-12
of the 14-22 MHz Oscillator .... 4-34 829 MHz 2nd Converter
............
5-13
REV JUN 1.983 iii

492/492P Service Vol. I (SN B030000 & up)
TABLE OF CONTENTS (cont)
Page
Sectio 5 THEORY OF OPERATION (co t)
110 MHz IF A plifier and 3rd
Converter ....................................... 5-20
110 MHz IF A plifier .................. 5-20
110 MHz Bandpass Filter .......... 5-21
3rd Converter.................................. 5-22
IF Section ....................................... 5-23
Variable Resolution Section ........ 5-23
Logarith ic A plifier and
Detector...................................... 5-29
Display Section................................ 5-31
Functional Description ................ 5-31
Video A plifier............................ 5-33
Video Processor ........................ 5-35
Digital Storage............................ 5-38
Vertical Section ...................... 5-39
Horizontal Section .................. 5-43
Deflection A plifiers .................. 5-45
Z-Axis Circuits ............................ 5-46
High Voltage Supply .................. 5-47
Crt Readout................................ 5-48
Frequency Control Section .............. 5-55
Sweep........................................ 5-55
Span Attenuator ........................ 5-58
1 st Local Oscillator Driver .......... 5-61
Preselector Driver ...................... 5-63
Sweep Shaper and Bias Circuits. 5-66
Center Frequency Control .......... 5-67
Phaselock Syste (Option 03) ........ 5-70
Functional Description ................ 5-70
Phaselock Control ...................... 5-71
Error A plifier and Synthesizer.. 5-73
Controlled Oscillator, Offset
Mixer, and Strobe Driver ............ 5-76
Digital Control.................................. 5-77
Processor.................................... 5-78
Me ory Board ............................ 5-87
Front Panel................................ 5-88
Accessories Interface Board .... 5-94
Main Power Supply and Fan Driver. 5-94
Page
Sectio 5 THEORY OF OPERATION (co t)
Main Power Supply.................... 5-94
492P GENERAL PURPOSE
INTERFACE BUS ...................... 5-98
Sectio 6 RACKMOUNT/BENCHTOP VERSIONS
Introduction ..................................... 6-1
Electrical Characteristics ................ 6-1
Standard Accessories.......................... 6-3
Optional Accessories............................ 6-3
Rack ounting Installation Di ensions. 6-3
Slide-Out Tracks.................................. 6-3
Mounting Procedure ........................ 6-4
Alternate Rear Mounting Methods. . 6-5
Slide-out Track Lubrication .............. 6 -6
Re oving or Installing the
492/492P Spectru Analyzer fro
or in the Rack ount Cabinet .......... 6 -6
Re oving the Side, Top, and
Botto Panels................................ 6-7
Installing Se i-rigid Coaxial
Cables to Access the Cabinet
Rear Panel Connectors to the
Front Panel of the Instru ent
(Option 31)...................................... 6-7
PREPARING THE INSTRUMENT FOR
CALIBRATION OR MAINTENANCE. . . 6-9
Appe dix A GLOSSARY
General Ter s...................................... A-1
Ter s Related to Frequency ................ A-2
Ter s Related to A plitude ................ A-2
Ter s Related to Digital Storage for
Spectru Analyzers............................ A-3
CHANGE INFORMATION
iv REV AUG 1981

492/492P Service Vol. I (SN B030000 & up)
TABLE OF CONTENTS (cont)
VOLUME 2
SERVICING SAFETY SUMMARY
Sectio 7 REPLACEABLE ELECTRICAL PARTS
Sectio 8 DIAGRAMS
Sectio 9 REPLACEABLE MECHANICAL PARTS
Digital Control
Syste Description
Processor
Me ory Board
Front Panel
Accessories Interface Board
Main Power Supply and Fan Driver
Main Power Supply
Fan Driver Board
REV AUG 1981 V

492/492P Service Vol. I (SN B030000 & up)
LIST OF ILLUSTRATIONS
Fig.
No. Page
The 492/492P Spectru Analyzer xii
1-1 Probe power connector pin o u t ................ 1-12
1-2 Di ensions............................................... 1-14
1-3 International power cord and plug
configuration for the 492............................ 1-20
3-1 Test equip ent setup for checking
frequency of the calibrator and the
accuracy of the frequency readout ............ 3-8
3-2 Test equip ent setup showing two ethods
that check calibrator output level .............. 3-10
3-3 Test equip ent setup for verifying
attenuator and gain accuracy.................... 3-12
3-4 Test equip ent setup for checking the
10 kHz—10 MHz frequency response .... 3-16
3-5 Test equip ent setup for easuring the
0.01—2.0 GHz frequency response .......... 3-17
3-6 Typical display showing frequency response
fro a sweeping signal source .................. 3-17
3-7 Test equip ent setup for easuring 2.0—
18.0 GHz frequency response.................... 3-19
3-8 Test equip ent setup for checking span and
ti ing accuracy ......................................... 3-21
3-9 Display to illustrate how ti ing accuracy
is checked................................................. 3-22
3-10 Measuring resolution bandwidth and
shape factor ............................................. 3-24
3-11 Typical display of drift easure ent without
phaselock showing width of arker stored
with MAX HOLD and beginning display of
arker saved in A ..................................... 3-27
3-12 Displays that illustrate how to easure resid
ual FM with PHASELOCK off. The sa e
technique is used with PHASELOCK on (Op
tion 03)..................................................... 3-27
3-13 Test equip ent setup for easuring
inter odulation distortion.......................... 3-28
3-14 Inter odulation products.......................... 3-28
3-15 Test equip ent setup to check har onic
distortion................................................... 3-29
3-16 Typical display of phaselock noise ............ 3-30
3-17 Multiple exposure to illustrate how the
differential between two signals can be
easured................................................... 3-31
3-18 Test equip ent setup for checking triggering
require ents............................................. 3-32
3-19 Test equip ent setup to check external
triggering and horizontal input
characteristics........................................... 3-33
vi
Fig.
No. Page
3-20 Test oscilloscope display of a sinewave
input signal to EXT TRIG connector (input
1.0 V peak at 2.0 V peak-to-peak) ............ 3-33
3-21 Display of a full screen signal at the
Vertical Output Connector ......................... 3-34
3-22 Low voltage power supply adjust ents
and test point locations ............................. 3-44
3-23 Adjust ents and test points on the
deflection a plifier, High Voltage odule,
and Z-Axis/RF Interface board.................. 3-45
3-23 Location of wire strap (W4036) on high
voltage circuit board ................................. 3-45
3-25 Test equip ent setup for calibrating the
Deflection A plifier ................................... 3-46
3-26 Location of TP1101 on Crt Readout ........ 3-47
3-27 Test points and adjust ents on the
Deflection A plifier board for gain and
frequency response calibration ................. 3-47
3-28 Test equip ent setup for calibrating sweep
ti ing ........................................................ 3-48
3-29 Location of ti ing adjust ent R5105 and
TP1061 on sweep board ........................... 3-49
3-30 Test equip ent setup for calibrating
sweep ra p for the 1 st LO Driver............ 3-50
3-31 1st LO balance and span adjust ents and
test points................................................. 3-51
3-32 Test equip ent setup for check and
adjust ent of 1 st and 2nd LO frequencies. 3-54
3-33 Center Frequency Control adjust ent
locations................................................... 3-55
3-34 1 st LO Driver adjust ents and test point
locations................................................... 3-57
3-35 Test equip ent setup for adjusting baseline
leveling....................................................... 3-58
3-36 Adjust ents and test points on the Video
Processor board....................................... 3-59
3-37 Typical response displays when adjusting
baseline leveling ....................................... 3-60
3-38 Typical response displays when adjusting
co pensation of baseline leveling circuits . 3-60
3-39 Equip ent setup for calibrating log
a plifier .................................................... 3-61
3-40 Location of connectors and adjust ents on
the Log and Video A plifier ..................... 3-62
3-41 Test equip ent setup for calibrating the
VR section................................................. 3-64
3-42 Calibration adjust ents on the VR #2
odule....................................................... 3-64
REV AUG 1981

492/492P Service Vol. I (SN B030000 & up)
LIST OF ILLUSTRATIONS (cont)
Fig. Page
No.
3-43 Response of the 100 kHz filter .................. 3-65
3-44 Calibration adjust ents on the VR #1
odule....................................................... 3-65
3-45 Typical response of 10 kHz, 100 kHz, and
1 MHz bandwidth filters ........................... 3-67
3-46 Test equip ent setup for adjusting IF gain
and the location of the calibrator level
adjust ent ................................................. 3-68
3-47A Digital Storage adjust ent
locations SN B043115 and above .......... 3-70
3-47 Digital Storage adjust ents
SN B043114 and below .......................... 3-70
3-48 Location of binary switch (S1014) for
setting B —SAVE A reference level ............ 3-71
3-49 Band leveling adjust ents and gain diodes
(when installed) on VR #2 odule ............ 3-72
3-50 Test equip ent setup for calibrating band
leveling of the external ixer bands .......... 3-73
3-51 Test equip ent setup for calibrating
Preselector Driver ..................................... 3-74
3-52 Preselector Driver adjust ents and test
points......................................................... 3-74
3-53 Test equip ent setupo for calibrating
Phaselock asse bly ................................. 3-76
3-54 Adjust ents and test point locations in the
Phaselock odule ..................................... 3-77
4-1 Multipin (har onica) connector
configuration ............................................. 4-4
4-2 Color code for so e tantalu capacitors. . 4-4
4-3 Diode polarity arkings............................ 4-5
4-4 Electrode configuration for se iconductor
co ponents ............................................... 4-6
4-5 Preparing the VR odule for service
showing how it is supported when on an
extender................................................... 4-9
4-6 RF deck of B040000 and up version
showing ajor ase blies.......................... 4-11
4-6A View of the 492/492P RF deck for
B039999 and below showing ajor
asse blies
and circuit boards ..................................... 4-12
4-7 View of the 492/492P top deck showing
ajor asse blies ....................................... 4-13
4-8 Re oving YIG oscillator interface circuit
board......................................................... 4-16
4-9 Fan Asse bly ........................................... 4-18
4-10 Test equip ent setup for adjusting return
loss for the 110 MHz IF asse bly ............ 4-20
4-11 Location of the 110 MHz IF return loss
adjust ents and IF Gain adjust ent ........ 4-20
Fig. Page
N o .
4-12 LO section of 829 MHz converter showing
test points and connectors ........................ 4-22
4-13 Location of test jack and ju per on the
829 MHz a plifier board ........................... 4-23
4-14 Test equip ent setup for aligning the
829 MHz filter ........................................... 4-24
4-15 Filter tune tabs in the 829 MHz converter . 4-25
4-16 Typical response when the first and
second resonators of the 829 MHz filter
are adjusted correctly ............................... 4-26
4-17 Typical response when the third and fourth
resonators are tuned correctly .................. 4-26
4-18 Test equip ent setup for calibrating
the oscillator section of the
2182 MHz Phaselocked 2nd L O ................ 4-28
4-19 Adjust ents and test point locations
within the oscillator section........................ 4-29
4-20 Construction of a coaxial test probe
for the 2182 MHz Phaselocked 2nd LO ... 4-30
4-21 Test equip ent setup for calibrating
the phaselocked section of the
2182 MHz Phaselocked 2nd L O ................ 4-31
4-22 Location of test points and co ponents
associated with calibrating the
14-22 MHz Phaselock circuit .................... 4-32
4-23 Ju per positions between T1077
and T1075 versus frequency
co pensation for the 14-22 MHz
Oscillator ................................................... 4-33
4-24 The Me ory board option switch band
S1033 ....................................................... 4-36
4-25 A15 through A12 in icroco puter test
ode ......................................................... 4-38
4-26 A15 and Y0 through Y2 of address decoder
U2044 ....................................................... 4-38
4-27 Enable and Y0 through Y2 of address de
coder U1037B ........................................... 4-39
4-28 A15 and Me ory board address decoder
outputs ..................................................... 4-40
4-29 A15 and Y0 through Y2 of address decoder
U1021 on the GPIB board ........................ 4-41
4-30 One enable and outputs LORAM, HIRAM,
and GPS of address decoder U1028 on the
GPIB board ............................................... 4-41
4-31 Instru ent bus check ............................... 4-41
5-1 Filter cross-section view ............................ 5-8
5-2 Filter equivalent circuit ............................... 5-9
5-3 2182.0 MHz Cavity LO equivalent circuits . 5-13
5-4 Diplexer si plified sche atic .................... 5-14
5-5 A plifier signal path ................................. 5-15
5-6 A plifier signal path ................................. 5-15
REV SEP 1983 vii

492/492P Service Vol. I (SN B030000 & up)
LIST OF ILLUSTRATIONS (cont)
Fig. Fig·
No. Page No. Page
5-7 Si plified block diagra of the phaselock 5-33 Flow chart of the 6800 ain decision
circuits....................................................... 5-17 paths....................................................... . 5-82
5-8 Bridged T attenuator equivalent sche atic 5-21 5-34 6821 PIA registers and control lines........... 5-84
5-9 Three-stage log a plifier............................ 5-30 5-35 A 6800 write to the instru ent bus
..........
. 5-87
5-10 Log a plifier gain curve showing 5-36 Instru ent bus poll sequence.................... 5-88
breakpoint................................................. 5-30 ς-37 Scan by si plified keyboard encoder
........ 5-89
5-11 Ends of logging range
...............................
5-30 5-38 Keyboard encoder
.....................................
5-90
5-12 Si plified detector circuit.......................... 5-32 5-39 Switch atrix codes
.................................
5-92
5-13 Selection of display position on log scale.. 5-33 5-40 Frequency control encoder ti ing ..............
5-93
5-14 Video filter si plified sche atic
................
5-37 5-41 Pri ary regulator input and output
5-15 Vertical control IC block diagra ..............
5-40 wavefor s (stylized)
.................................
5-96
5-16 Horizontal control IC block diagra
..........
5-44 5-42 Ti ing wavefor s (stylized) for soft-start
5-17 Si plified crt readout block diagra
........ 5-48 circuit ........................................................
5-97
5-18 Character on/off ti ing.............................. 5-49 5-43 9914 GPIA block diagra
......................... 5-100
5-19 Character scan
......................................... 5-50 6-1 Hardware provided for slide track
5-20 Character generator (U1028) block diagra 5-51 ounting................................................... 6-3
5-21 Character scan ti ing ...............................
5-52 6 -2 Instru ent installed in a cabinet-type
5-22 Dot delay circuit ti ing.............................. 5-53 6-4
5-23 Frequency dot arker circuit and ti ing .. 5-54 6-3 Co plete slide-out track asse blies
........
6-5
5-24 Sweep "interrupt" circuits.......................... 5-59 6-4 Method of ounting the stationary
5-25 Si plified digital-to-analog converter
........
5-60 sections..................................................... 6 -6
5-26 Si plified span decade attenuator
............
5-61 6-5 Measure ents of front-rail ounting
5-27 DAC variance graph .................................
5-67 holes for the stationary sections................ 6-7
5-28 Basic tune voltage converter
....................
5-68 6 -6 Procedure for inserting or re oving
5-29 Ti ing diagra for F ERROR count
.......... 5-73 the instru ent........................................... 6 - 8
5-30 Si ple Logic diagra of processor clock.. 5-79 6-7 Align ent adjust ent for correct
5-31 Block diagra of 6800 icroprocessor ... 5-80 operation................................................... 6-9
5-32 Read and write cycle ti ing on the 6 -8 Alternative ethod of installing the
icroco puter bus ...................................
5-81 instru ent using rear support brackets ... 6 -1 0

i
■ 492/492P Se /ice Vol. I (SN B030000 & up)
LIST OF TABLES
Table Table
No. Page No. Page
1-1 Electrical Characteristics
...........................
1-4 4-11 Front-Panel Registers.............................. 4-47
1-2 Environ ental Characteristics.................... 1 - 1 2 4-12 Sweep Registers
.....................................
4-47
1-3 Physical Characteristics............................ 1-13 4-13 Span Attenuator Registers (75 and 76) .. . 4-48
1-4 Option 01 Electrical Characteristics ..........
1-15 4-14 1st LO Driver Registers (72 and 7E)
..........
4-48
1-5 Option 03 Electrical Characteristics
..........
1-17 4-15 Preselector Driver Control (77)
................ . 4-49
2-1 Shipping Carton Strength
.........................
2 -2 4-16 Center Frequency Control Registers
3-1 Equip ent Required for Calibration
.......... 3-1 (70, 71, and F0).......................................... 4-49
3-2 Har onic Nu ber (n) vs Frequency 4-17 Phaselock Control Registers (73 and F3)... 4-49
Range ....................................................... 3-7 5-1 RF Interface Lines
................................... . . 5-5
3-3 Correction Factor To Deter ine True 5-2 2nd Converter IF Selection......................... 5-7
Signal Level............................................... 3-13 5-3 Switch and A plifier Selection Su ary... 5-16
3-4 Reco ended Test Equip ent for 5-4 Bandwidth Selection
.................................
5-24
Measuring Frequency Response................ 3-15 5-5 Gain Step Co binations............................ 5-26
3-5 Narrow and Wide Spans vs Frequency 5-6 Progression of Gain Reduction .................. 5-27
Band......................................................... 3-20 5-7 Filter Co ponent Co binations
................
5-37
3-6 Span/Div vs Ti e Markers........................ 3-22 5-8 J2039 Truth Table
.....................................
5-46
3-7 492/492P Sensitivity
................................. 3-25 5-9 Control Port............................................... 5-53
3-8 Sensitivity (Option 01) ...............................
3-26 5-10 Address/Data P ort
...................................
5-53
3-9 Adjust ent Steps for Calibration
..............
3-42 5-11 Sweep Rate Selection Codes
.................... 5-58
3-10 Power Supply Voltage Tolerances
............ 3-43 5-12 Calibration Control Selection Codes
.......... 5-60
3-11 Resolution and Sweep Rate as a Function 5-13 Attenuation Selection Codes
...................... 5-61
of Span in Auto Mode ...............................
3-49 5-14 U4017 (U3027) Output Lines
....................
5-62
3-12 Ext Mixer Band Leveling Adjust ents .... 3-73 5-15 U5031 Output Lines
.................................
5-64
4-1 Relative Susceptibility to Static Discharge 5-16 Preselector Frequency Bands
....................
5-65
Da age..................................................... 4-1 5-17 ADDRESS 70 For ats
............................. 5-69
4-2 Equip ent Required ................................. 4-18 5-18 DAC Tuning Codes
...................................
5-69
4-3 Equip ent Required for 2nd LO 5-19 U2025 Output Lines.................................. 5-75
Calibration................................................. 4-26 5-20 Condition Codes
.......................................
5-78
4-4 Equip ent Required for Calibrating 5-21 Address Select Lines................................ 5-83
14-22 MHz Phaselock Circuit.................... 4-29 5-22 492/492P Microco puter Address Space . 5-83
4-5 Variable Resolution Data Register
............ 4-44 5-23 PIA Register and Interface Select Codes.. 5-85
4-6 Log & Video A p Registers...................... 4-45 5-24 Instru ent Bus Register Addresses
.......... 5-86
4-7 Video Processor Control (7C).................... 4-45 5-25 Parallel POLL Byte.................................... 5-87
4-8 Digital Storage Registers (7A, FA, and 7B) 4-45 5-26 GPIA Registers
.........................................
5-101
4-9 Z-Axis and RF Deck Control (4F)
..............
4-46 6-1 Environ ental Characteristics
....................
6-1
4-10 Crt Readout Registers (5F and 2F)
............ 4-46 6 -2 Physical..................................................... 6 -2
I
L
IREV AUG 1981
I
I

492/492P Service Vol. I (SN B030000 & up)
SERVICING SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Do Not Service Alone
Do not perfor internal service or adjust ent of this prod
uct unless another person capable of rendering first aid and
resuscitation is present.
Use the Proper Fuse
To avoid fire hazard, use only the fuse specified in the parts
list for your product, and which is identical in type, voltage
rating, and current rating.
Use Care When Servicing With Power On
Dangerous voltages exist at several points in this product.
To avoid personal injury, do not touch exposed connections
and co ponents while power is on.
Disconnect power before re oving protective panels, sol
dering, or replacing co ponents.
Power Source
This product is intended to operate fro a power source
that will not apply ore than 250 volts r s between the
supply conductors or between either supply conductor and
ground. A protective ground connection by way of the
grounding conductor in the power cord is essential for safe
operation.
Refer fuse replace ent to qualified service personnel.
Do Not Operate in Explosive Atmospheres
To avoid explosion, do not operate this product in an at o
sphere of explosive gases unless it has been specifically
certified for such operation.
SYMBOLS
In This Manual
Δ
|\ This sy bol indicates where applicable cau
tionary or other infor ation is to be found.
As Marked on Equipment
DANGER—High voltage.
TERMS
In This Manual
CAUTION state ents identify conditions or practices that
could result in da age to the equip ent or other property.
WARNING state ents identify conditions or practices that
could result in personal injury or loss of life.
As Marked on Equipment
CAUTION indicates a personal injury hazard not i ediate
ly accessible as one reads the arking, or a hazard to prop
erty including the equip ent itself.
DANGER indicates a personal injury hazard i ediately ac
cessible as one reads the arking.
AProtective ground (earth) ter inal.
ATTENTION—refer to anual.
Power Source
This product is intended to operate fro a power source
that will not apply ore than 250 volts r s between the
supply conductors or between either supply conductor and
ground. A protective ground connection by way of the
grounding conductor in the power cord is essential for safe
operation.
Grounding the Product
This product is grounded through the grounding conductor
of the power cord. To avoid electrical shock, plug the power
cord into a properly wired receptacle before connecting to
the product input or output ter inals. A protective ground
xREV AUG 1981

492/492P Service Vol. I (SN B030000 & up)
The 492/492P Spectru Analyzer.
xii REV AUG 98

Section —492/492P Service Vol. I (SN B030000 & up)
GENERAL INFORMATION
AND SPECIFICATION
GENERAL INFORMATION
I troductio
The Service anual consists of two volu es that contain
infor ation necessary to test, adjust, and service the Porta
ble Rack ount/Benchtop 492/492P Spectru Analyzer.
The intent is to provide as co plete infor ation as possible
as an aid in servicing this instru ent. The Table of Contents
at the beginning of Volu e 1 lists contents of each section
contained within Volu e 1.
Change infor ation that involves anual corrections
and/or additions pending anual reprint and bind, is located
at the back of the Service anual in the CHANGE INFOR
MATION section.
History infor ation with the updated data is integrated
into the text or diagra s when a page or diagra is updat
ed. Revised pages have a revision date in the lower inside
corner of the page. The anual ay contain revisions that
do not apply to your instru ent; however, history infor a
tion with updated data, is integrated into the text or diagra
when the page or diagra is revised.
The person using these instructions should be knowl
edgeable in digital and analog circuit theory. Circuit analysis
is pri arily functional. The intent is to provide sufficient in
for ation for the technician to isolate the ajority of al
functions to a block of circuitry. Those users with an
understanding of logic and analog circuitry should then be
able to further isolate the alfunction to a specific co po
nent or co ponents.
Most ter inology is in accordance with those standards
adapted by IEEE. A glossary of ter s is provided as an
appendix. Abbreviations in the docu entation are in accor
dance with ANSI Y1.1-1972, with exceptions and additions
explained in parentheses after the abbreviation. Graphic
sy bols co ply with ANSI Y32.2-1975. Logic sy bology is
based on ANSI Y32.14-1973 and the anufacturer’s data
description. A copy of ANSI standards ay be obtained
fro the Institute of Electrical and Electronic Engineers, 345
47th Street, New York, NY 10017.
Product Service
To assure adequate product service and aintenance for
our instru ents, Tektronix has established Field Offices and
Service Centers at strategic points throughout the United
States and in countries where our products are sold. Sever
al types of aintenance or repair agree ents are available.
For exa ple: for a fixed fee, a aintenance agree ent pro
gra provides aintenance and re-calibration on a regular
basis. Tektronix will re ind you when a product is due for
recalibration and perfor the service within a specified ti e.
Contact your local Service Center, representative, or sales
engineer for details regarding: Warranty, Calibration, E er
gency Repair, Repair Parts, Scheduled Maintenance, Main
tenance Agree ents, Pickup and Delivery, On-Site Service
for fixed installations, and other services available through
these centers.
Tektronix e ergency repair service provides i ediate
attention to instru ent alfunctions if you are in an e er
gency situation such as a field trip. Again, contact any
Tektronix Service Center for assistance to get you on your
way within a ini u of ti e.
I strume t Co structio
The odular construction of the 492/492P instru ent
provides ready access to the ajor circuits. Circuit boards
that contain sensitive circuits are either ounted on etal
extrusions, each of which provides shielding between adja
cent odules, or they are ounted within honeyco blike
extrusions with a feedthrough connector through the wall of
the co part ent. Interconnection between boards and as
se blies is provided by plugging these boards onto a ain
other board. Most adjust ents and test points are acces
sible while the instru ent is operational and the odules or
asse blies secured in their nor al position. Extenders are
provided with a Service Kit; see Maintenance section under
Service Fixtures and Tools for Maintenance.
Any odule can be re oved without disturbing the struc
tural or functional integrity of the other odules. The ex
tenders allow ost circuit board asse blies to function in
an extended position for service or adjust ent. The circuit
REV JUN 982 -

Specification—492/492P Service Vol. I (SN B030000 & up)
boards ounted on the etai extrusion can be re oved by
re oving the securing screws. All other circuit boards
(which should require ini al service) are accessible by re
oving a cover plate.
NOTE
Disassembly of some mo ules may require special
tools an proce ures. These proce ures will be foun
in the Maintenance section.
In instru ents that have phase lock, the phase lock as
se bly contributes to the 492/492P stability. Circuits are
co pletely rf isolated to ensure spurious free response, yet
the close proxi ity ini izes losses or interactions with
other functions. All co part ents are enclosed on both
sides by etal plates and all interconnections between co 
part ents are ade by feedthrough ter inals rather than
cables. If the co part ents are opened, be sure that the
shields and covers are properly reinstalled before operating.
Elapsed Time Meter
A 5000 hour elapsed ti e indicator, graduated in 500
hour incre ents, is installed on the Z Axis/RF Interface cir
cuit board. This provides a convenient way to check operat
ing ti e. The eter on new instru ents ay indicate fro
200 to 300 hours elapsed ti e. Most instru ents go
through a factory burn-in ti e to i prove reliability. This is
si ilar to using aged co ponents to i prove reliability and
operating stability.
Changing Power Input Range
The following procedures describe how to set the input
power range.
a. Disconnect the power plug and re ove the cover.
b. Re ove the access plate at the upper left corner
(viewed fro the rear) of the power odule.
c. Shift plug P1029 to the appropriate pins on J1029 as
indicated by the silk screen no enclature. Replace the ac
cess plate.
NOTE
The earlier version power supply mo ule i not have
this access plate. To access P1029 procee as
follows:
1) Set the instrument on its face an remove the four
screws that hol the power supply mo ule to the si e
rails. Lift the mo ule off the instrument.
2) Remove the top an bottom screws then the si e
screw that hol s the two sections of the power supply
mo ule together. Separate the two sections to ex
pose the power supply circuit boar .
3) Shift the plug P1029 (upper left comer) to the ap
propriate pins on J1029. Re-install the two sections
an the power supply mo ule.
d. Re ove the input power specification plate over the
input fuse on the back panel. Turn the plate over and
reinstall so the exposed infor ation on power specifications
is correct.
e. Change the input fuse to the new value specified on
the infor ation plate.
f. Replace the cover and the power cord; then connect
the instru ent to the appropriate power source.
NOTE
The power cor supplie with the instrument an in
strument power voltage requirements epen on the
available power source (see the Specification part of
this section for power cor options).
Replacing Fuses
Besides the input (back panel) fuse, the 492/492P power
odule has five fuses for the dc supplies (+300 V, F3014;
+ 100 V, F1034; +17 V, F1014; +9 V, F1031; -7V,
F1011). Access to these fuses can be gained by re oving
the access plate at the upper right corner of the power od
ule, or by separating the two sections as described for
changing the input power range. Fuses are identified with
sta ped circuit nu bers on the circuit board.
Selected Components
So e co ponents, such as icrocircuits, are selected to
eet Tektronix specifications. These co ponents are indi
cated in the parts list and carry a Tektronix Part Nu ber
under the Mfr. Part Nu ber colu n.
Selected value co ponents that co pensate for para 
eter differences between active co ponents are identified
-2 REV FEB 982

Specification—492/492P Service Vol. I (SN B030000 & up)
on the circuit diagra and in the parts list as a "SEL" value.
The co ponent description lists either the no inal value or
a range of value. If the procedure for selection is not obvi
ous, such as setting the gain or response of a stage, the
criteria for selection is explained in the Calibration or Main
tenance section of the anual. Where the selection proce
dure is obvious, such as establishing the frequency of an
oscillator, no procedure is given.
Component Circuit Numbering Scheme
In this instru ent, circuit nu bers were assigned accord
ing to the co ponents physical location on the board. For
exa ple, a co ponent such as a resistor, located within
row 2 colu n 08, is R2080. The fourth digit of the nu ber is
an expander used to designate two or ore co on co 
ponents within a given grid, such as R2080, R2082, etc.
Chassis ounted co ponents are assigned a three digit
nu ber to help identify their location.
The Replaceable Electrical Parts list prefixes these circuit
nu bers with an asse bly nu ber. R2080, on asse bly
A20, beco es A20R2080. Asse bly and subasse bly
nu bers are assigned in nu erical order by location within
the instru ent.
Firmware Version and Error Message Readout
This feature of the 492/492P provides readout of the
fir ware version when the power on/off is cycled. During
initial power-up cycle, the fir ware version flashes on
screen for approxi ately two seconds. The Replaceable
Electrical Parts list section, under Me ory Board (A54), lists
the ROM’s and their Tektronix part nu ber for each
fir ware version.
An additional feature is error essage readout. The fol
lowing is a list of these essages and their eaning.
Error
No. Mea i g
57 Tune routine failed in carry fro lower DAC.
58 Failed to phase lock.
59 Lost lock.
60 Failed to recenter when phase lock cancelled or
when going to an unlocked span.
Rackmount/Benchtop Versions
The rack ount version of the 492/492P Spectru Ana
lyzer is the 492/492P in a rack ount cabinet. Access to all
front panel connectors is provided with Option 31 of this
version. Additional cooling is provided and a front panel ac
cessories drawer in the cabinet provides storage for ost
accessories. The benchtop version is the sa e as the
rack ount with the exception of the side rails.

Specification—492/492P Service Vol. I (SN B030000 & up)
SPECIFICATION
The following list of instru ent characteristics and fea
tures apply to the basic 492/492P Spectru Analyzer after
a 30- inute war up, except as noted. Changes to the basic
specifications due to the addition of options follow the basic
listings.
Differences in the electrical and environ ental character
istics for the rack ount/bench versions of the 492/492P are
described in the Rack ount/Benchtop section of this an
ual. Refer to section 6 for this infor ation.
The Perfor ance Require ent colu n describes the li 
its of the characteristic, and the Supple ental colu n de
scribes features and typical values or infor ation that ay
be useful to the user. Procedures to verify perfor ance re
quire ents are provided in the Calibration section of the
Service instructions. The Perfor ance Check procedures
require sophisticated equip ent as well as technical exper
tise to perfor .
The Operators Manual contains a procedure that checks
all functions of the 492/492P. This check is reco ended
for inco ing inspections to verify that the instru ent is func
tioning properly.
Table -
ELECTRICAL CHARACTERISTICS
Characteristic Performance Requirement Supplemental Information
FREQUENCY RELATED
Center Frequency
Range (Internal Mixer) 50 kHz to 21 GHz Frequency response degraded by 1 dB before
100 kHz.
Accuracy
(after 2 hour war up) ±(5 MHz + 20% of span/div) n or ± (0.2% of the center frequency + 2 0 %
of the span/div) whichever is greater.
Readout Resolution Within 1 MHz.
TUNE co and accuracy
(492P only under re ote con
trol) after a 2 hour war up.
1 st LO Tuning
Band Freq Span/Div
1-3 > 50 kHz
4 >100 kHz
5-11 >200 kHz
± (7% of tune a ount or ± 150 kHz) n
whichever is greater. (See listing of IF fre
quency, LO range, and har onic nu ber
that follows, for value of n.)
2nd LO Tuning
1-3 < 50 kHz
4 <100 kHz ± (7% of tune a ount)
5-11 «200 kHz
Repeatability accuracy (return
to a previous frequency
setting) with an a bient
te perature change < 10°C
(492P only under re ote con
trol).
Residual FM (short ter )
after 2 hour war up *£(1 kHz peak-to-peak) n for a period
of 20 s, n is the 1 st LO har onic
nu ber used in the 1 st ixer conversion,
and related to the selected frequency
range (band).
No video filter.
±(2 MHz + 10% of Span/Div) or ±(0.1% of
frequency + 10% of Span/Div) whichever is
greater.
-4 REV NOV 982

Specification—492/492P Service Vol. I (SN B030000 & up)
Table - (cont)
Characteristic Perfor ance Require ent Supple ental Infor ation
Frequency Drift after 2 hour
war up at a fixed frequency
and stable a bient
te perature
«=200 kHz/hour, funda ental ixing. A re-stabilization ti e of 10 inutes per GHz
of frequency change ust be allowed if the
1st LO frequency is retuned.
"Static" Resolution Band
width (6 dB down) 1 kHz to 1 MHz in decade steps, plus an
auto atic (AUTO position). Resolution
bandwidth (6 dB down) is within 20% of
the bandwidth selected.
In AUTO position the bandwidth is co puted
by an internal co puter, based on the
span/div, video filters, ti e/div, and
vertical display selections. When both
the TIME/DIV and RESOLUTION BANDWIDTH
are in AUTO position, the resolution
bandwidth is a function of the FREQUENCY
SPAN/DIV selection.
Shape Factor (60 dB/6dB) 7.5:1 or less.
Noise Sidebands At least —75 dBc at 30 ti es the resolu
tion offset for funda ental ixing.
Pulse Stretcher
Fall-Ti e 30 Ms/division; ±50%.
Video Filter
Narrow Reduces video bandwidth to approxi ately
1/300th of the selected resolution bandwidth.
Wide Reduces video bandwidth to approxi ately
1 /30th of the selected resolution bandwidth.
Frequency Span/Div
Range (in 1-2-5 sequence) Band Narrow
Span Wide Span
1—3
(0—7.1 GHz) 10 kHz/Div 200 MHz/Div
4—5
(5.4—21 GHz) 50 kHz/Div 500 MHz/Div
6
(18—26 GHz) 50 kHz/Div 1 GHz/Div
7—8
(26—60 GHz) 100 kHz/Div 2 GHz/Div
9
(60—90 GHz) 200 kHz/Div 2 GHz/Div
10
(90—140 GHz) 500 kHz/Div 5 GHz/Div
11
(140—220 GHz) 500 kHz/Div 10 GHz/Div
Two additional positions provide full band (MAX
span) display or 0 Hz (ti e do ain) display.
Accuracy Within 5% of the span/div selected over
the center eight divisions of a ten-
division display.
REV NOV 982 -5

Specificatio —492/492P Service Vol. I (SN B030000 & up)
Table 1-1 (co t)
Characteristic Performance Requirement Supplemental Information
IF Frequency, LO Range
and Har onic Nu ber (n)
Band and Freq Range LO Range (MHz) and 1st IF
Har onic (n) (MHz)
1 (0 — 4.2 GHz) 2072 — 6272 (1 -) 2072
2(1.7 — 5.5 GHz) 2529 — 6329 (1 -) 829
3(3.0 — 7.1 GHz) 2171 — 6271 (1+) 829
4(5.4 — 21.0 GHz) 2072 — 6276 (3-) 829
5(15 — 21 GHz) 4309 — 6309 (3 + ) 2072
6(18 — 26 GHz) 2655 — 3988 (6 + ) 2072
7 (26 — 40 GHz) 2443 — 3793 (10 + ) 2072
8 (40 — 60 GHz) 3792 — 5790 (10 + ) 2072
9 (60 — 90 GHz) 3861 — 5862 (15 + ) 2072
10(90 — 140 GHz) 3823 — 5997 (23 + ) 2072
11 (140 — 220 GHz) 3728 — 5890 (37 + ) 2072
AMPLITUDE RELATED
Display Modes 10 dB/Div, 2 dB/Div, Linear, and
Delta A.
Display Reference Level
Range — 123 dB to +40 dB (+40 dB includes
10 dB of IF gain reduction). +30 dB or 1 W is
the axi u safe input for 10 dB/DIV and
2 dB/DIV log odes. 20 nV/Div to 2 V/Div (1 W
axi u safe input) in linear ode.
Steps 10 dB, 1 dB, and 0.25 dB for relative
(Δ) easure ents in log ode. 1 -2-5
sequence and 1 dB equivalent incre ents
in LIN ode.
Accuracy Accuracy is a function of the RF attenuation, IF
gain, resolution bandwidth, display ode, refer
ence level, frequency band and response. Refer
to accuracies of these characteristics
The input RF attenuator steps 10 dB for refer
ence level changes above —30 dB or
—20 dB when MIN NOISE ode is active un
less the MIN RF ATTEN setting is greater than
nor al. The IF gain increases 10 dB for each
10 dB reference level change below —30 dB
(-2 0 dB for MIN NOISE ode).
REV JUN 982 -7

• F
f t Specification—492/492P Service Vol. I (SN B030000 & up)
Table - (cont)
Characteristic Perfor ance Require ent Supple ental Infor ation
Display Dyna ic Range 80 dB at 10 dB/Div and 16 dB for 1-9 dB/Div
and 8 divisions for linear ode.
Accuracy ±1.0 dB/10 dB to a axi u cu ulative
error of ±2.0 dB over the 80 dB window
and ± 0.4 dB/2 dB to a axi u cu u
lative error of ±1.0 dB over the 16 dB
window. LIN ode is ± 5% of full screen.
RF Attenuator
Range 0 to 60 dB in 10 dB steps.
Accuracy3
Dc to 4 GHz Within 0.3 dB/10 dB to a axi u of
0.7 dB over the 60 dB range.
4 GHz to 18 GHz Within 0.5 dB/10 dB to a axi u of
1.4 dB over the 60 dB range.
IF Gain
Range 93 dB of gain increase, 10 dB of gain
decrease (MIN NOISE activated) in 10 dB
and 1 dB steps.
Accuracy Gain steps are onotonic (sa e direction)
with the following li its: Within 0.2 dB/dB
to a axi u of 0.5 dB/9 dB except at
the decade transitions of — 19 to
-2 0 dB , -2 9 to -3 0 dB , -3 9 to
—40 dB , —49 to —50 dB , —59 to
—60 dB and —69 to —70 dB , where
an additional 0.5 dB can occur for a total
of 1.0 dB per decade. Maxi u deviation
of the 90 dB range is within ±2 dB.
Differential A plitude
Measure ent
Range
Delta A ode provides differential easure
ents in 0.25 dB incre ents
10 dB above to 40 dB below the reference level
established when the delta A ode was
activated.
DO NOT use the delta A ode outside the
— 123 dB to +30 dB reference level range.
Accuracy dB Difference Steps Error
0.25 dB 1 0.05 dB
2 db 8 0.4 dB
10 dB 40 1.0 dB
50 dB 200 2.0 dB
Signal A plitude Variation
With Resolution Switching Less than 0.5 dB
f t
IIII
IIIIR
I
I
■Refer o “Verifica ion of Tolerance Values” a he beginning of he Performance Check sec ion.
-8 REVJUN 982

Specification—492/492P Service Vol. I (SN B030000 & up)
Table - (cont)
Characteristic Performance Requirement Supplemental Information
Sensitivity
The following tabulation shows the equivalent axi u input noise for each resolution bandwidth, with the internal
ixer for frequency bands 1—5 (100 kHz—18 GHz), and TEKTRONIX High Perfor ance Waveguide Mixers for bands
6—10 (18 GHz—140 GHz). The NARROW video filter is activated, for narrow resolutions (1 kHz or less); WIDE filter for wide
resolution.
SENSITIVITY (VERSUS BANDWIDTH)
Frequency/Band Equivalent Input Noise for Resolution Bandwidths
1 kHz 10 kHz 100 kHz 1 MHz
50 kHz—7.1 GHz (Bands 1—3) — 115 dB -105 dB — 95 dB — 85 dB
5.4-18.0 GHz (Band 4) -100 dB — 90 dB —80 dB — 70 dB
15—21.0 GHz (Band 5) -9 5 dB -8 5 dB -7 5 dB -65 dB
18.0—26 GHz (Band 6)a -100 dB -9 0 dB -8 0 dB -7 0 dB
26—40.0 GHz (Band I f —95 dB —85 dB -7 5 dB —65 dB
40.0—60.0 GHz (Band 8)a -9 5 dB —85 dB -75 dB —65 dB
60.0—90.0 GHz (Band 9) Typically —95 dB for 1 kHz bandwidth at 60 GHz degrading to —85 dB at 90 GHz
90.0—150.0 GHz (Band 10) Typically —85 dB for 1 kHz bandwidth at 90 GHz degrading to —75 dB at 140 GHz
140.0—220 GHz (Band 11) External Mixer Dependent
Spurious Response
Residual (no input signal,
referenced to ixer input,
and funda ental ixing for
bands 1, 2, and 3)
— 100 dB or less
Third order inter odulation
products (MIN DISTORTION
ode)
At least — 70 dBc below any two on
screen signals within any frequency
span
Har onic Distortion (cw
signal, MIN DISTORTION
ode)
At least —60 dBc for full screen signal
LO E issions (referenced to
input ixer) — 10 dB or less
‘ TEKTRONIX High Performance Waveguide Mixers.
REVJUN 982 1-9