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OPERATORS Part No. 070-4418-00
MANUAL Product Group 26
r
r
494/494P
SPECTRUM ANALYZER
I
i
Please Check for
CHANGE INFORMATION
at the Rear of This Manual
First Printing OCT 1983
Revised NOV 1986
TiPAtronix
m..arren ro fI-ELLEN
A
A
494/494P Operators
PREFACE
This manual is one of a set of product manuals for the ANSI and IEEE standards may be obtained 'from, the Insti-
TEKTRONIX 494 and 494P (programmable) Spectrum Ana- tute of Electrical and Electronic Engineers Inc ., 345 East
lyzer. It describes the installation and operation of the 47th Street, New York, N .Y . 10017 .
494/494P Spectrum Analyzer . These instructions assume
the user is knowledgeable about frequency domain analysis .
Our intent is to explain the operation of the 4941494P so
that meaningful measurements can be made under adverse Change/History Information
as well as laboratory conditions . The manual organization Change information that involves manual corrections
and content is listed in the Table of Contents . Programming and/or additional information pending manual reprint and
information is in a separate Programmers manual, and ser- bind is located at the back of this manual in a CHANGE
vice information is contained in a two-volume Service INFORMATION section.
manual .
History information, with the updated data, is integrated
Standards and Conventions Used into the text when the page(s) is revised. A revised page is
identified by a revision date located in the lower left corner
Most terminology is in accordance with those standards
of the page (e .g ., REV JAN 1984).
adapted by IEEE and IEC . A glossary of terms is provided
as an appendix . Abbreviations in the documentation are in
accordance with ANSI Y1 .1-1972, with exceptions and addi-
tions explained in parentheses after the abbreviation . Unpacking and Preparation for Use
Graphic symbols comply with ANSI Y32 .2-1975 . Logic sym-
bology is based on ANSI Y32.14-1973 and the manufactur- Instructions for unpacking and preparing the instrument
er's data description . GPIS functions for the programmable for use are described under "Preparing the Instrument for
version conforms to IEEE 488-1978 Standard . A copy of Use" which follows.
494/494P Operators
TABLE OF CONTENTS
Page Page
PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Section 5 TURN-ON PROCEDURE AND
LIST OF ILLUSTRATIONS . . . . . . . . . . . . . . _ . . . . . iv OPERATIONAL CHECK
LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Firmware Version and Error Message
OPERATORS SAFETY SUMMARY . . . . . . . . . . , . . v Readout . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
SERVICE SAFETY SUMMARY . . . . . . . . . . . . . . . . . vii Firmware Version . . . . . . . . . . . . . . . 5-1
Error Message Readout . . . . . . . , . . 5-1
Section 1 GENERAL INFORMATION Turn On Procedure and Preparation for
Product Overview . . . . . . . . . . . . . . . 1-1 Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Options for Power Cord 1 . Initial Turn On . . . . . . . . . . . . . . 5-1
Configuration . . . . . . . . . . . . . . . . . . 1-1 2. Calibrate Center Frequency,
Options . . . . . . . . . . . . . . . . . . . . . . . 1-1 Reference Level, and Dynamic
Accessories . . . . . . . . . . . . . . . . . . . 1-1 Range . . . . . . . . . . . . . . . . . . . . 5-2
Firmware Version and Error Message Functional or Operational Check . . . . . . 5-3
Readout . . . . . . . . . . . . . . . . . . . . . . 1-3 Equipment Required . . . . . . . . . . . . . 5-3
Preliminary Preparation . . . . . . . . . . 5-3
Section 2 SPECIFICATION 1 . Check Operation of Front Panel
Introduction . . . . . . . . . . . . . . . . . . . . 2-1 Pushbuttons and Controls . . . . 5-3
Electrical Characteristics . . . . . . . . . . . . 2-1 2. Check Gain Variation Between
Resolution Bandwidths . . . . . . . 5-9
Section 3 INSTALLATION AND PREPARATION 3. Check Counter Accuracy . . . . . 5-10
FOR USE 4. Check Span Accuracy and
Introduction . . . . . . . . . . . . . . . . . . . . 3-1 Linearity . . . . . . . . . . . . . . . . . . . 5-10
Unpacking and Initial Inspection . . 3-1 5. Check Resolution Bandwidth
Power Source and Power and Shape Factor . . . . . . . . . . . 5-10
Requirements . . . . . . . . . . . . . . . . . . 3-1 6 . Check Reference Level Gain and
Repackaging for Shipment . . . . . . . . 3-2 RF Attenuator Steps . . . . . . . . . 5-10
Storage . . . . . . . . . . . . . . . . . . . . . . . 3-3 7 . Check Sensitivity . . . . . . . . . . . . 5-11
8. Check Residual FM . . . . . . . . . . 5-13
9. Check Frequency Drift or
Stability . . . . . . . . . . . . . . . . . . . 5-14
Section 4 CONTROLS, CONNECTORS, AND
10 . GPIB Verification Program . . . . 5-14
INDICATORS
Introduction . . . . . . . . . . . . . . . . . . , 4-1 Section 6 GENERAL OPERATING PROCEDURE
Shift Functions of the Pushbuttons 4-1 Firmware Version and Error Message
Instrument Power Control . . . . . . . . 4-1 Readout . . . . . . . . . . . . . . . . . . . . . . 6-1
Crt Controls . . . . . . . . . . . . . . . . . . . 4-2 Using the Help Feature . . . . . . . . . . 6-1
Sweep or Scan . . . . . . . . . . . . . . . . 4-2 Crt Light Filters . . . . . . . . . . . . . . . . 6-1
Display Parameters . . . . . . . . . . . . . 4-3 Intensity Level and Beam Alignment 6-1
General Purpose Pushbuttons . . . . 4-9 Signal Application . . . . . . . . . . . . . . 6-1
494P (GPIB) Controls . . . . . . . . . . . 4-9 Resolution Bandwidth, Frequency
Front-Panel Input/Output Connectors 4-10 Span, and Sweep Time . . . . . . . . . . 6-2
Rear-Panel Input/Output Connectors 4-10 Using the MANUAL PEAK Control or
Un-Nomenclated Front Panel AUTO PEAK Mode . . . . . . . . . . . . . 6-3
Pushbutton Functions . . . . . . . . . . . . . . 4-12 Using the Signal Identifier . . . . . . . . 6-3
Operational Functions . . . . . . . . . . . 4-12 Using the Video Filters . . . . . . . . . . 6-4
Service Related Functions . . . . . . . . 4-12 Time Domain Operation . . . . . . . . . 6-5
REV MAY 1984
4941494P Operators
TABLE OF CONTENTS (cont)
Page Page
Section 6 GENERAL OPERATING PROCEDURE Section 6 GENERAL, OPERATING PROCEDURE
(cant) {cont)
Triggering the Display . . . . . . . . . . . 6-5 Connecting to a System . . . . . . . . . 6-16
Sweeping the Display . . . . . . . . . . . 6-5 Operational Precautions for the
Manual Scan of the Spectrum . . . . 6-5 494/494P . . . . . . . . . . . . . . . . . . . . . . . . 6-16
Reference Level, RF Attenuation, and Service Manual . . . . . . . . . . . . . . . . . 6-17
Vertical Display . . . . . . . . . . . . . . . . 6-6 Product Service . . . . . . . . . . . . . . . . 6-17
JA Mode . . . . . . . . . . . . . . . . . . . . . 6-6
Using Min Noise or Min Distortion
Mode . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Section 7 OPTIONS
Digital Storage . . . . . . . . . . . . . . . . . 6-7
Option 08 . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Store/Recall Feature . . . . . . . . . . . . 6-8
Option 12 . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Using the Counter . . . . . . . . . . . . . . 6-8
Option 13 . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Using the Automatic Calibration
Option 14 . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Feature . . . . . . . . . . . . . . . . . . . . . . 6-8
Option 20 . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Un-Nomenclated Front Panel
Option 21 . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Pushbutton Functions . . . . . . . . . . . 6-8
Option 22 . . . . . . . . . . . . . . . . . . . . . . . . 7-3
External Mixers and Diplexer . . . . . 6-9
Options 30, 31, and 32
Reference Level Readout and
(Rackmount/Benchtop Versions) . . . . . . 7-4
Conversion Loss for External Mixers 6-9
Option 30 . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Handling . . . . . . . . . . . . . . . . . . . . . . 6-10
Option 31 . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Installation . . . . . . . . . . . . . . . . . . . . 6-10
Option 32 . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Operation . . . . . . . . . . . . . . . . . . . . . 6-11
Options 30, 31, and 32 Environmental
494P GPIB Controls, Indicators, and
Characteristics . . . . . . . . . . . . . . . . . . . . 7-4
Connectors . . . . . . . . . . . . . . . . . . . . . . 6-11
Safety Requirements . . . . . . . . . . . 7-6
GPIB Function Readout . . . . . . . . . 6-11
Accessories . . . . . . . . . . . . . . . . . . . 7-6
RESET TO LOCAL (REMOTE) , . . . 6-11
Option 41 . . . . . . . . . . . . . . . . . . . . . . . . 7-6
ADDRESSED . . . . . . . . . . . . . . . . . 6-12
Option 52 . . . . . . . . . . . . . . . . . . . . . . . . 7-6
PLOT . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Setting the GPIB ADDRESS
Switches . . . . . . . . . . . . . . . . . . . . . 6-13
Talk/Listen-Only Operation . . . . . . . 6-13 Appendix A GLOSSARY
TALK ONLY, LISTEN ONLY General Terms . . . . . . . . . . . . . . . . . . A-1
Switches . . . . . . . . . . . . . . . . . . . . . 6-13 Terms Related to Frequency . . . . . . A-1
Data Logging . . . . . . . . . . . . . . . . , . 6-14 Terms Related to Amplitude . . . . . . A-2
Restoring Control Settings and the Terms Related to Digital Storage for
Display . . . . . . . . . . . . . . . . . . . . . . . 6-15 Spectrum Analyzers . . . . . . . . . . . . A-3
494/494P Operators
LIST OF ILLUSTRATIONS
Fig. Fig.
No . Page No . Page
494/494P Spectrum Analyzer . . . . . . . . . . . viii 6-3 Graph to illustrate the relationship between
2-1 Probe power connector . . . . . . . . . . . . . . . . 2-12 d6m, d6mV and c1BjuV (matching attenuator
2-2 Dimensions . . . . . . . . . . . . . . . . , . . . . . . . . 2-14 included where necessary) . . . . . . . . . . . . . 6-3
3-1 International power cord configuration 6-4 Typical display generated by a signal into the
(Option A1-A5) for 4941494P . . . . . . . . . . . 3-2 waveguide mixer . . . . . . . . . . . . . . . . . . 6-4
4-1 Front panel selectors, controls, and 6-5 Identifier mode displays . . . . . . . . . . . . . . . . 6-4
connectors . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 6-6 Integrating the display with the Video Filter 6-5
4-2 Rear panel connectors on the 494/494P . . 4-11 6-7 Using B -SAVE A to observe the differential
5-1 Crt display and readout for power-up state 5-1 between SAVE A and B displays . . . . . . . . 6-7
5-2 Typical display of calibration markers in MAX 6-8 Diagram showing external waveguide mixer
SPAN position . . . . . . . . . . . . . . . . . . . . . . . 5-2 installation . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
5-3 Integrating a display with the Video Filter . 5-5 6-9 Typical display from an external mixer . . . . 6-11
5-4 Using IDENT feature to identify a real or true 6-10 GPIB selectors and indicators unique to the
response . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6 494P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
5-5 Displays that illustrate how bandwidth and 6-11 Status of GPIB as shown on the crt readout 6-12
shape factor are determined . . . . . . . . . . . . 5-11 6-12 GPIB ADDRESS switch on the rear panel . 6-13
5-6 Typical display showing how to determine 6-13 TEKTRONIX 4924 Digital Cartridge Tape
residual FM . . . . . . . _ . . . . . . . . . . . . . . . . . 5-14 Drive in a Talk/Listen Only system . . . . . . . 6-14
6-1 Volts/dBm-Watts conversion chart for 50 SZ 6-14 Controls on the 4924 and 494P that are used
impedance . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 to the Talk/Listen Only transfers . . . . . . . . . 6-15
6-2 Circuit of a 75 to 50 S2 matching pad (ac 7-1 International power cord and plug
coupled) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 configuration for the 494/494P . . . . . . . . . . 7-1
LIST OF TABLES
Table Table
No . Page No . Page
1-1 Standard Accessories . . . . . . . . . . . . . . . . . 1-2 2-11 494/494P Safety Standard and Regulatory
1-2 Tektronix High Performance Waveguide Requirement Conformance . . . . . . . . . . . . . 2-15
Mixers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 3-1 Shipping Carton Test Strength . . . . . . . . . . 3-3
2-1 Frequency Related Characteristics . . . . . . . 2-1 5-1 494/494P Sensitivity . . . . . . . . . . . . . . . . . . 5-13
2-2 IF Frequency, LO Range, and Harmonic 7-1 Power Cord Options . . . . . . . . . . . . . . . . . . 7-1
Number (N) . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 7-2 Option 20 (General Purpose Waveguide
2-3 Amplitude Related Characteristics . . . . . . . 2-5 Mixers) Characteristics . . . . . . . . . . . . . . . . 7-2
2-4 Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8 7-3 Option 21 (WM 490-2) Characteristics . . . . 7-3
2-5 Input Signal Characteristics . . . . . . . . . . . . 2-9 7-4 Option 22 (WM 490-3) Characteristics . . . . 7-3
2-6 Output Signal Characteristics . . . . . . . . . . . 2-10 7-5 Options 30, 31, & 32 Environmental
2-7 General Characteristics . . . . . . . . . . . . . . . . 2-11 Characteristics . . . . . . . . _ . . . . . . . . . . . . . 7-5
2-8 Power Requirements . . . . . . . . . . . , . . . . . . 2-12 7-6 Options 30, 31, & 32 Physical
2-9 Environmental Characteristics . . . . . . . . . . . 2-12 Characteristics . . . . . . . . . . . . . . . . . . . . . . . 7-5
2-10 Physical Characteristics . . . . . . . . . . . . . . . 2-14
iv
494(494P Operators
OPERATORS SAFETY SUMMARY
The information in this safety summary is for both DANGER indicates a personal injury hazard immediately
operating and servicing personnel . Specific warnings and accessible as one reads the marking .
cautions will be found throughout the manual where they
apply, but may not appear in this summary.
SYMBOLS
CONFORMANCE TO INDUSTRY In This Manual
STANDARDS This symbol indicates where applicable
cautionary or other information is to be found.
The 494/494P complies with the following Industry
Safety Standards and Regulatory Requirements :
As Marked on Equipment
Safety
0
DANGER - High voltage .
CSA--Electrical Bulletin
Protective ground (earth) terminal .
FM-Electrical Utilization Standard Class 3820 ATTENTION - refer to manual .
ANSI 039.5-Safety Requirements for Electrical
and Electronic Measuring and Controlling
Instrumentation . POWER
IEC 348 (2nd addition)-Safety Requirements for
Power Source
Electronic Measuring Apparatus .
This product is intended to operate from a power source
that will not apply more than 250 V rms between the supply
Regulatory Requirements conductors or between either supply conductor and ground .
A protective ground connection by way of the grounding
VDE 0871 Class B-Regulations for RFI Suppression of
conductor in the power cord is essential for safe operation .
High Frequency Apparatus and Installations .
Grounding the Product
This product is grounded through the grounding conduc-
TERMS tor of the power cord . To avoid electrical shock, plug the
power cord into a properly wired receptacle before connect-
In This Manual ing it to the product input or output terminals . A protective
CAUTION statements identify conditions or practices ground connection by way of the grounding conductor in the
that could result in damage to the equipment or other power cord is essential for safe operation .
property .
Danger From Loss of Ground
WARNING statements identify conditions or practices
Upon lass of the protective-ground connection, all acces-
that could result in personal injury or loss of life .
sible conductive parts (including knobs and controls that
may appear to be insulating) can render an electric shock .
As Marked on Equipment
CAUTION indicates a personal injury hazard not immedi- Use the Proper Power Cord
ately accessible as one reads the marking, or a hazard to Use only the power cord and connector specified for your
property, including the equipment itself . product .
494/494P Operators
Use only a power cord that is in good condition . OPERATIONAL PRECAUTIONS
Do Not Operate in Explosive Atmosphere
For detailed information on power cords and connectors,
To prevent an explosion, do not operate this product in
see Figure t-3.
an explosive atmosphere unless it has been specifically cer-
tified for such operation .
Refer cord and connector changes to qualified service
personnel .
Use the Proper Fuse
To avoid fire hazard or damage to the equipment, use
Do Not Remove Covers or Panels
only the fuse of correct type, voltage rating, and current
rating (as specified in the Replaceable E=lectrical Parts list in To avoid personal injury, do not remove the product cov-
Volume 2 of the Service manual) for your product . Refer ers or panels . Do not operate the product without the cov-
fuse replacement to qualified service personnel, ers and panels properly installed .
494/494P Operators
SERVICE SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Refer also to the preceding Operators Safety Summary
Do Not Service Alone before removing protective panels, soldering, or replacing
Do not perform internal service or adjustment of this components.
product unless another person capable of rendering first aid
and resuscitation is present .
Power Source
Use Care When Servicing With Power On This product is intended to operate from a power source
that will not apply more than 250 V rms between the supply
Dangerous voltages exist at several points in this prod- conductors or between either supply conductor and ground.
uct . To avoid personal injury, do not touch exposed connec- A protective ground connection, via the grounding conduc-
tions and components while power is on. Disconnect power tor in the power cord, is essential for safe operation .
494/494P Operators
4941494P Spectrum Analyzer .
Viii
Section 1-4941494P Operators
GENERAL INFORMATION
Product Overview The 494P adds remote control capability to the standard
instrument features of the 494. The front-paned controls (ex-
The 494 and the 494P programmable instruments are cept those intended for local use, such as INTENSITY) can
high performance, compact, portable spectrum analyzers.
be remotely operated through the GPIB port, which allows
Microcomputer control of most functions simplifies and en- the 494P to be used with a variety of systems and control-
hances operation. Its main features are ; synthesizer fre-
lers . This operation is described in detail in - the Program-
quency accuracy and stability, precision signal counting mers manual .
ability, precise amplitude measurement capability, digital
storage display, non-volatile memory to retain front panel
settings and displays, and crt message readout that de- The rackmount version (Option 30) of the 494/494P
scribes function of the front panel controls and selectors Spectrum Analyzer is the instrument in a cabinet designed
along with messages that explain operating errors .
to mount in a standard 19-inch rack . Option 31 includes
semi-rigid cabling from the front panel connectors (e .g ., RP
INPUT, 1st LO, 2nd L0, etc .) to the back of the cabinet .
The frequency range is 10 kHz to 21 GHz with the inter- This provides access to all front-panel connectors via the
nal mixer, and up to 325 GHz when using external wave-
cabinet rear panel .
guide mixers . A minimum resolution bandwidth of 30 Hz,
with a minimum span of 50 Hzldlv, provides measurement
resolution that is commensurate with the frequency accu- The benchtop version (Option 32) is the 494 or 494P in
racy . Digital storage provides flicker free displays plus func- the rackmount version cabinet with the addition of side pan-
tions such as SAVE A, B -SAVE A, MAX HOLD with which els and feet on the bottom of the cabinet. Both rackmount
to compare and subtract displays, save maximum values . In and benchtop cabinets include a larger (external) fan for ad-
addition to the conventional digital storage feature, up to
ditional cooling . This fan must be installed and operating
nine separate displays with their parameter readouts, can before applying power to the instrument .
be stored in non-volatile memory, then later recalled for ad-
ditional analysis and comparison . Up to ten different front-
panel control setups can also be stored for future recall .
Options For Power Cord Configuration
Tektronix has implemented options that provide interna-
Center frequency may be selected by means of the front- tionally approved power cord and plug configurations .
panel tuning knob or directly selected by the Data Entry These are listed and illustrated in the Options section of this
keyboard . When using the keyboard, it is not necessary to manual .
alter the Span/Div setting regardless of the frequency se-
lected . Other parameters, such as vertical display and refer-
ence level, may also be keyboard selected with the flexibility
previously available only under GPIB program control . Options
Counter accuracy to 1 Hz resolution is available . Options for the 494/494P are described in the Options
section of the manuals including rack mountlbenchtop
versions .
In addition, the 494/494P requires only a short warm-up
time for stable operation . In 15 minutes or less the fre-
quency drift is less than 500 Hz per minute of sweep time .
Accessories
After one hour, it is less than 50 Hz per minute of sweep
time . Display dynamic range is 80 dB, with calibrated refer- Standard accessories that come with each instrument
ence level readout from -117 dBm to A-30 dBm, in are listed in Table 1-1, In addition there are optional acces-
selectable steps from 1 to 15 dB, and 0 .25 dB for a delta A sories such as ; waveguide mixer sets, Tracking Generators,
(amplitude) mode . When the vertical display is selected with etc. Table 1-2 lists Tektronix waveguide mixers that are
the Data Entry keyboard, the reference level steps corre- available. Standard accessories, with part numbers, are
spond to the display mode (see General Operating informa- listed in Volume 2 of the service instructions, following the
tion in Section 6) . Sensitivity at 30 Hz resolution bandwidth Replaceable Mechanical Parts list . Optional accessories
is -121 dBm to 7 .1 GHz, decreasing to -96 dBm at such as cables and adapters are listed, where appropriate,
21 GHz . throughout the manual and in the Tektronix catalog.
REV MAR 1984
General Information-494/494P Operators
Table 1-1
STANDARD ACCESSORIES
50 ohm coaxial cable, n to n connector, 72 -
Front Cover or Drawer
50 ohm Coax cable, bnc to bnc connector, 18"
Front Cover or Drawer
Adapter, n male to bnc female
Front Cover or Drawer
Fuses, 4 A fasta
Front Cover or Drawer
Power cord
Front Cover or Drawer
Cord clamp
Front Cover or Drawer
Crt light filter, amber
Front Cover or Drawer
Crt light filter, grey
Front Cover or Drawer
Crt mesh filter
Front Cover or Drawer
Diplexer Assembly,
Front Cover or Drawer
Adapter, tnc to sma
Part of Diplexer Assy
Cable, semi-rigid coaxial
Part of Diplexer Assy
Visor, crt
Front Cover or Drawer
Manual, Operators Handbook
Front Cover or Drawer
Manual, Operators
Not applicable
Manual, Service, Volume 1
Not applicable
Manual, Service, Volume 2
Not applicable
Manual, Programmers (494P only)
Not applicable
GPIB interconnect cable (494P only)
Not applicable
"The power cord and fuses are replaced with an appropriate
power cord for the power cord option (Al, A2, A3, A4, A5) and the fuses
are charged to 2A slow blow . Option 52 (North American
Configuration for 220 V with standard power cord) replaces fuses with 2A
slow brow.
4Deleted for Option 08 instruments .
Table 1-2
TEKTRONIX HIGH PERFORMANCE WAVEGUIDE MIXERS
Nomenclature Frequency Range
WM 490K
18 to 26 .5 GHz
W M 490A
26 .5 to 40 GHz
WM 490U
33 to 60 GHz
WM 490V
50 to 75 GHz
WM 490E
60 to 90 GHz
WM 490W
75 to 110 GHz
WM 490F
90 to 140 GHz
WM 490D
110 to 170 GHz
WM 490G
140 to 220 GHz
G-J Band flange transistion
220 to 325 GHz
General Information-494/494P Operators
Firmware Version and Error Message Readout An additional feature is error message readout . If the
microcomputer fails to complete any routine or function, an
This feature of the 494/494P provides readout of the
error message will flash on screen explaining the nature of
firmware version when the power on/off is cycled . During
the error (i .e ., failed to complete phase lock) .
initial power-up cycle, the firmware version flashes on
screen for approximately two seconds. The Replaceable
Electrical Parts list section, under Memory Board (A54), lists
the ROM's and their Tektronix part number for each firm-
ware version.
Section 2-49414194P Operators
SPECIFICATION
Introduction
This section includes electrical, physical, environmental, this specification, due to options are listed in the Options
and safety characteristics of this instrument . Changes to section .
ELECTRICAL CHARACTERISTICS
The following tables of electrical characteristics and fea- The instrument microprocessor performs an internal cali-
tures apply to the 494/494P Spectrum Analyzer after a bration check each time power is turned on and verifies that
30-minute warmup, except as noted . The Performance Re- the instrument frequency and amplitude performance is as
quirement cofumn defines some characteristics in quantita- specified . An operation or functional check procedure, which
tive terms and in limit form . The Supplemental column does not require external test equipment or technical exper-
explains performance requirements or provides perfor- tise, is provided in the operators instructions to satisfy most
mance information . Statements in this column are not con- incoming inspections and help familiarize the operator with
sidered to be guaranteed performance and are not ordinarily the capabilities of the instrument .
supported by a performance check procedure. Procedures
to verify performance requirements are provided in the Per-
formance section of the service manual .
Table 2-1
FREQUENCY RELATED CHARACTERISTICS
Characteristic Performance Requirement Supplemental Information
Center Frequency Range (internal 10 kHz to 21 GHz. Tuned by the front
mixer) panel knob or front panel Data Entry
keyboard .
Accuracy (after the front panel CAL Accuracy of the center frequency is a
has been performed) function of the accuracy do which the
center frequency is set between sweeps
(covered by CF accuracy specification),
and the amount of center frequency drift
during a sweep. Center frequency drift
can be significant during the first 30 min.
after turn-on, or after a change in ambient
temperat u re.
Bands 1 & 5-12 with Span/Div [(20% of Span/Div or Resoln Refer to "IF Frequency, LO Range, and
X200 kHz, and Bands 2-4, with Bandwidth, whichever is greater) ; -+- Harmonic Number" specification for value
Span/Div > 100 kHz (CF X ref freq error) + (N X 15 kHz)] of N . The 1st LO is unlocked in these
spans .
When the center frequency is changed
within a band, a settling time of 1 s/GHz
change in center frequency, divided by N
should be allowed.
Bands 1 & 5-12 with SpanIDiv " x(20% of Span/Div or Resoln The 1st LO is phase locked in these
`200 kHz and bands 2-4 with Bandwidth, whichever is greater) ; f spans
SpanlDiv ~_ 10 0 kH z (CF X ref freq error) i (2N + 25)Hz
REV MAR 1984
Specification-494/494P Operators
Table 2-1 (cont)
Characteristic Performance Requirement Supplemental Information
CF Drift (constant ambient Since the center frequency is corrected
temperature and fixed center frequncy) before each sweep the only error
observed is during sweep time,
After 30 minute warmup :
Bands 1 & 5-12 with Span/Div --(25 kHz)N per minute of sweep time
X200 kHz, and Bands 2-4 with
Span/Div > 100 kHz
Bands 1 & 5-12 with Span/Div X150 Hz per minute of sweep time
--200 kHz Bands 2-4 with
Span/Div -- 100 kHz
After 1 hour warmup :
Bands 1 & 5-12 with Span/Div _(5 kHz) N per minute of sweep time
X200 kHz and Bands 2-4 with
Span/Div X100 kHz
Bands 1 & 5-12 with Span/Div --50 Hz per minute of sweep time
_200 kHz and Bands 2-4 with
Span/Div -- 100 kHz
Readout Resolution At least 10% of Span/Div
Signal Counter Accuracy +[(Counter frequency X frequency
reference error) + (10 + 2N)Hz + 1
LSD]
Sensitivity Signal level at center screen must
20 dB or more above the average
noise level and within 60 dB of the
Reference Level
Readout Resolution 1 Hz through 1 GHz, selectable with
COUNT RESOLN control
Reference Frequency Error
Aging Rate 1X10-7 for first six months then less
than 1 X10-7 per year
Accuracy during warmup at 25