Tektronix 495p schematic

Instrument Serial Numbers

Each instrument manufactured by Tektronix has a serial number on a panel insert or tag, or stamped on the
chassis. The first letter in the serial number designates the country of manufacture. The last five digits of the
serial number are assigned sequentially and are unique to each instrument. Those manufactured in the
United States have six unique digits. The country of manufacture is identified as follows:

B010000 Tektronix, Inc.,
E200000 Tektronix United
J300000
H700000 Tektronix Holland, NV, Heerenveen, The Netherlands

Instruments manufactured for Tektronix by external vendors outside the United States are assigned a two digit
alpha code to identify the country of manufacture (e.g., JP for Japan, HK for Hong Kong,

Tektronix, Inc., RO.
Printed in U.S.A.
Copyright © Tektronix, Inc., 1992. All rights reserved. Tektronix products are covered by U.S. and foreign

patents, issued and pending. The following are registered trademarks: TEKTRONIX, TEK, TEKPROBE, and
SCOPE-MOBILE.

Sony/Tektronix,

Box

500, Beaverton, OR 97077

Beaverton,

Kingdom,

Japan

Oregon, USA

Ltd., London

IL

for Israel, etc.).

WARRANTY

Tektronix warrants that this product will be free from defects in materials and workmanship for a period of
one (1) year from the date of shipment. If any such product proves defective during this warranty period,

Tektronix, at its option, either will repair the defective product without charge for parts and labor, or will provide

a replacement in exchange for the defective product.

In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the
expiration of the warranty period and make suitable arrangements for the performance of service. Customer
shall be responsible for packaging and shipping the defective product to the service center designated by

Tektronix, with shipping charges prepaid. Tektronix shall pay for the return of the product to Customer if the

shipment is to a location within the country in which the Tektronix service center is located. Customer shall be

responsible for paying all shipping charges, duties, taxes, and any other charges for products returned to any

other locations.

This warranty shall not apply to any defect, failure or damage caused by improper use or improper or

inadequate maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to

repair damage resulting from attempts by personnel other than Tektronix representatives to install, repair or

service the product; b) to repair damage resulting from improper use or connection to incompatible

equipment; or c) to service a product that has been modified or integrated with other products when the effect

of such modification or integration increases the time or difficulty of servicing the product.

THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THIS PRODUCT IN LIEU OF ANY

OTHER

IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

TEKTRONIX1 RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND

EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY. TEKTRONIX

AND ITS VENDORS WILL NOT BE LIABLE FOR ANY

CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS
ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

WARRANTIES,

EXPRESSED OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY

INDIRECT,

SPECIAL, INCIDENTAL, OR

This manual is one of a set of product manuals for the Tektronix 495 and

programmable 495P Spectrum Analyzers. The manual describes the instru-

ment installation and operation. These instructions assume a thorough

knowledge of frequency domain analysis. The purpose of this manual is to
explain the operation of the 495 and 495P so that measurements will be
meaningful whether made under adverse or laboratory conditions. The
manual organization is shown in the Table of Contents. The manuals that are

available in addition to this 495/495P User Manual include the following:

Standards and

Conventions

Change/History

Information

• 495/495P Service

• 495P Programmer Manual (standard accessory for 495P Option only)

For manual ordering information, contact your local Tektronix Field Office or
representative or refer to the Accessories portion of the Replaceable

chanical Parts list in the 495/495P Service Manual, Volume 2.

Most terminology is consistent with standards adapted by IEEE and IEC. A

glossary of terms is provided in Appendix A. Abbreviations in the documen-

tation are consistent with ANSI

IEEE 488-1978 standard. Copies of ANSI and IEEE standards can be
ordered from the Institute of Electrical and Electronic Engineers Inc.

Any change information that involves manual corrections or additional
information is located behind the Change Information page at the back of

this manual.

Manuals,

Volume 1 and 2

Y1.1-1972.

GPIB

functions conform

Me-

to

the

Unpacking and

Initial Inspection

Storage and

Repackaging

495 & 495P User Manual

Instructions for unpacking and preparing the instrument for use are de-

scribed in Section 3.

Instructions for short- and long-term storage and instrument repackaging for

shipment are described in Section 3.

Preface

IF

Preface

495 & 495P User Manual

Table of Contents

/v

Contents

Operation

Table of Contents

495 & 495P User Manual

Table of Contents

vi

Contents

495 & 495P User Manual

vu

List of Figures

via

Contents

495 & 495P User Manual

flf

List of Tables

Contents

Please take a moment to review these safety precautions. They are provided
for your protection and to prevent damage to the spectrum analyzer. This
safety information applies to all operators and service personnel.

Symbols

and

Terms

These

two

terms

aPPear

statements identify conditions or practices that could result in

damage to the equipment or other property.

|

WARNING

l

statements

personal injury or loss of life.

These two terms appear on equipment:

• CAUTION indicates a personal injury hazard not immediately accessible
as one reads the marking, or a hazard to property including the equip-

ment itself.

• DANGER indicates a personal injury hazard immediately accessible as

one reads the marking.

in

manuals:

identify

conditions

or

practices

that

could

result

in

495 & 495P User Manual

XI

Safety

Specific

PreC3UtionS

Observe

prevent damage to either the spectrum analyzer or equipment connected to
it.

all of

these

precautions

to

ensure

your

personal

safety

and to

Power Source

The spectrum analyzer is intended to operate from a power source that will
not

apply

more

than

250

VRMS

between
either supply conductor and ground. A protective ground connection,
through the grounding conductor in the power cord, is essential for safe

system operation.

the

supply

conductors

or

Grounding the Spectrum Analyzer

The spectrum analyzer is grounded through the power cord. To avoid elec-

tric shock, plug the power cord into a properly wired receptacle where earth

ground has been verified by a qualified service person. Do this before mak-

ing connections to the input or output terminals of the spectrum analyzer.

Without the protective ground connection, all parts of the spectrum analyzer

are potential shock hazards. This includes knobs and controls that may

appear to be insulators.

between

Use the Proper Power Cord

Use only the power cord and connector specified for your product. Use only
a power cord that is in good condition.

Use the Proper Fuse

To avoid fire hazard, use only the fuse specified m the parts list for your

product, matched by type, voltage rating, and current rating.

Do Not Remove Covers or Panels

To avoid personal injury, do not operate the spectrum analyzer without the

panels or covers.

Electric Overload

Never apply to a connector on the spectrum analyzer a voltage that is out­side the range specified for that connector.

Do Not Operate in Explosive Atmospheres

The spectrum analyzer provides no explosion protection from static dis-

charges or arcing components. Do not operate the spectrum analyzer in an

atmosphere of explosive gases.

Xfi

Safety

Safety

XIV

Safety

Product Overview

The TEKTRONIX 495 and programmable 495P Spectrum Analyzers are high
performance, compact, portable instruments. Microcomputer control of most
functions simplifies and enhances operation.

The following is a list of the main instrument features:

• Single and delta marker modes

• Synthesizer frequency accuracy

• Precision signal counting ability

• Precise amplitude measurement capability

• Digital storage display

• Internal memory to retain front-panel settings and displays

• HELP messages (CRT readout) that describe the function of front-panel
keys and controls as well as messages that explain operating errors

• Front-panel DATA ENTRY push buttons

• Ability to plot the display, readout, and graticule

• Ability to hold 8 personalized macros in memory (programmable instru-

ments only)

• 10 Hz to 3 MHz resolution

495 & 495P User Manual

Basic Features

The frequency range is 100

bandwidth of 10 Hz, with a minimum span of 10 Hz/Div, provides measure­ment resolution that is proportional to the frequency accuracy. Digital stor-

age provides flicker-free displays plus SAVE A, B-SAVE

to compare and subtract displays and save maximum values. In addition to

conventional digital storage features, internal memory stores up to nine
separate displays with their readouts and dot markers, which can be re­called later for additional analysis and comparison. It is also possible to

store up to ten different front-panel control setups for future recall. The

signal counting feature allows the instrument to selectively count a particular
signal out of several that may be present at its input.

Hz

to 1800 MHz. A minimum resolution

A,

and MAX HOLD

1-1

General Information

Select center frequency either by the front-panel CENTER/MARKER FRE­QUENCY control or by the Data Entry push buttons. When using the Data
Entry push buttons, it is not necessary to alter the Span/Div setting regard­less of the frequency selected. Other parameters, such as vertical display
and reference
available only under program control of the general purpose interface bus

(GPIB).

level,

are push button selectable with the flexibility previously

Markers

The single and delta markers provide direct readout of frequency and ampli­tude information of any point along any displayed trace. Relative (delta)
frequency and amplitude information between any two points along any
displayed trace or between traces is also available. The CENTER/MARKER
FREQUENCY control can move the markers, or it can move the display with
a stationary frequency marker. For additional marker information, refer to
Using the Markers Feature in Section 6 of this manual.

Programmable Instrument Features

Firmware Version and
Error Message

Readout

The programmable version of the instrument adds remote control capabili­ties to the manual instrument features. The front-panel controls (except
those intended exclusively for local use, such as INTENSITY) can be re­motely operated through the GPIB port. This allows the spectrum analyzer to
be used with a variety of systems and controllers. Refer to the 495P Pro-
grammer Manual for additional information.

The programmable instrument also adds the macroinstructions (macros)

feature. The instrument memory has 8 kbytes reserved for the construction

of

made-to-order

macros for easy access. Specific macro information is located in the 495P

macros. The macro menu can hold the titles of eight

Programmer Manual.

This feature provides a readout that identifies the version of firmware that is
installed. The readout is momentarily displayed when the power is turned
on. The programmable instrument will flash the firmware version, in addition
to the GPIB address, when the [RESET TO LOCAL] key is pressed.

If the instrument fails to complete any routine or function, an error message
will flash on the screen explaining the failure.

7-2

General Information

General Information

Accessories

The Replaceable Mechanical Parts list in the 495/495P

Service

Manual,

Volume 2, contains the part numbers, descriptions, and ordering informa-

tion for all standard and optional accessories offered at this time.

The following list includes all standard accessories currently shipped with

each instrument. Refer to Section 7, Options, for alternate information.

• 50 Q coaxial cable; N to N connector, 72 inch

• 50 0 coaxial cable; BNC to BNC connector,

18

inch

• Adapter; N male to BNC female

• 4A fast-blow

• Power

cord

fuses1;

1

2 each

• Cord clamp

• CRT light filters; 2 - one each amber and grey

• CRT mesh filter

• Rear connector shield

• 495 & 495P User Manual

• 495P Programmer Manual; 495P Only

Options

Section 7, Options contains information on all of the options currently avail-

able for the 495 and

1

1f

the instrument is wired for 220-240 V operation (Options A1, A2, A3, A4,

Option 52 is installed (North American configuration for 220 V with standard power cord),

2A medium-blow fuses are used.

495R

AS)

or if

495 & 495P User Manual

7-3

General Information

1-4

General Information

This section includes the electrical, physical, and environmental characteris-

tics of this instrument. Any instrument specification changes due to options
are listed in Section 7, Options.

Electrical

Characteristics

The following tables of electrical characteristics and features apply to the

spectrum analyzer after a
front-panel CAL adjustments, except as noted.

• The Performance Requirement statements define characteristics that are
essential to the intended application of the product. Performance
quirement characteristics are normally verifiable by following the

mance Check procedure in the 495/P Service Manual, Volume

• The Supplemental Information column provides more explanation about

related Performance Requirements, or describes typical performance for
characteristics not ordinarily verified by the Performance Check proce­dure.

The instrument performs an internal processor system check each time

power is turned on. The Functional or Operational Check procedure is
provided in Section 5, Instrument Check Out. This procedure will satisfy most
incoming inspections and will help familiarize you with the instrument capa-

bilities. It does not require external test equipment or technical expertise.

30-minute

warmup, and after performing the

Re-

Perfor-

1.

Verification of Tolerance Values

Perform compliance tests of specified
quirement column, only after a 30-minute warm-up time (except as noted)
and after doing the front-panel CAL procedure. Use measurement instru-

ments that do not affect the values measured. Measurement tolerance of

test equipment should be negligible when compared to the specified toler-

ance. When the tolerance of test equipment is not negligible, the error of the

measuring device should be added to the specified tolerance.

limits,

listed in the Performance Re-

495 & 495P User Manual

2-1

Specification

Tabie

2-1:

Frequency Related Characteristics

Characteristic

Center/Marker Frequency

Range

Drift

After 30 minute warmup

SPAN/DIV

(1stl_O

SPAN/DIV < 200

(1stl_O

After 1 hour warmup

SPAN/DIV >200 kHz

(1stLO

SPAN/DIV < 200

(1stl_O

>200 kHz

Unlocked)

kHz

Locked)

Unlocked)

kHz

Locked)

Performance Requirement

<50

Hz per minute

Supplemental Information

100

Hz

to

1.8

GHz.

Tuned by the CENTER/MARKER

FREQUENCY control or the DATA
ENTRY push buttons.

With constant ambient temperature

and fixed center frequency.

Typically

Typically < 150 Hz per minute.

Typically < 5 kHz per minute.

<25

kHz per minute.

Not significant when compared to
residual FM per minute of sweep

time.

Correction will occur at the end of
sweep for sweep times > 5

s/div.

Readout Resolution

Initial Accuracy

SPAN/DIV >200 kHz

(1stLO

SPAN/DIV < 200

(1stLO

Unlocked)

Locked)

kHz

±[20%D + (CF x

REF)

+ 15 kHz]

where:

D=SPAN/DIV or RESOLUTION

BANDWIDTH,

whichever is greater

CF=Center Frequency

REF=Reference Frequency Error

±[20%D + (CF x REF) + 15 Hz]

where:

D=SPAN/DIV

or RESOLUTION

BANDWIDTH, whichever is greater

CF=Center Frequency

REF=Reference Frequency Error

At least

10%

of SPAN/DIV.

Allow a settling time of one second

for each GHz change in CF.

2-2

Specification

Table

2-1:

Frequency Related Characteristics (Cont.)

Specification

Characteristic

Reference Frequency Error

Aging Rate

Short Term
First 6 months

After first 6 months

Accuracy

+25° C 30 Minutes After

During

Warmup at

Power Up

Temperature Sensitivity

Setability

Signal Counter

Accuracy

(After 30 Minute Warmup)

Performance Requirement

Supplemental Information

<1

x 10~9/Day.

<

1 x

10~7 in first 6 months.

x 10~7/Year.

Within 5 x

10~8 of the frequency

after 24 hours.

Within 2 x

10~8 over

the instru-

ment operating temperature range

of -15° C to +55° C (referenced

to +25° C).

<1 x 10~

7

+20°

range.

Cto

+30° C temperature

100

MHz CAL OUT Refer-

ence.

±

[Counter frequency x Reference Count at center, marker, or A mark-

frequency error) + 5 Hz + 1 LSD]

ers.

Sensitivity

Readout Resolution

Residual FM

SPAN/DIV

(1stLO

SPAN/DIV < 200

(1stLO

>200 kHz

Unlocked)

kHz

Locked)

Static Resolution Bandwidth

(6 dB down)

Shape Factor (60 dB/6 dB)

60

dB

Bandwidth

for

the

10

Filter

Line-related Sidebands

Hz

<

Signal level, at center screen or at
marker, must be 20 dB or more
above the average noise level and
within 60 dB of the reference level.

<

7 kHz total excursion in 20 ms

<5

Hz total excursion in 20 ms

Within 20% of selected bandwidth

for

all but the 1 0

7.5:1

or less for all but the

Hz

filter

10

Hz

filter

150

Hz

<

-55 dBc (47 to 440 Hz)

1 Hz to

selectable with COUNT RESOLU-

TION menu.

100

MHz in decade steps,

Short term, after 1 hour warmup.

10

Hz to 1 MHz in decade steps,

and 3 M Hz.

495 & 495P User Manual

2-3

Specification

Table

2-1:

Frequency Related Characteristics (Cont.)

Characteristic

Noise Sidebands

Performance Requirement

<

-70

dBc

at 30X the selected

Supplemental Information

bandwidth for resolution band­widths of 10 Hz and

<

-75 dBc at 30X the selected

100

Hz

bandwidth for all other resolution
bandwidths

Video Filter Normal

3 MHz
1 MHz

100kHz

10kHz

1 kHz

100 Hz

10 Hz

Pulse Stretcher Fall-Time

30

us/div

(typical).

Frequency Span/Div

Range

10

Hz/divto

1 -2-5 sequence with the

DIV

control), or

170

MHz/div (from the DATA

ENTRY push buttons) to two signif-

icant digits.

In addition, MAX SPAN provides a
full-band display, and ZERO SPAN

provides a 0 Hz display. With
ZERO SPAN, the horizontal axis is
calibrated in

Frequency/div.

Wide

30kHz
30kHz

3kHz

300 Hz

30 Hz

3 Hz
3 Hz

of pulse amplitude

100

MHz/div

(in a

SPAN/

10

Hz/div

Time/div

to

instead of

Narrow

3kHz
3kHz

300 Hz

30 Hz

3 Hz

0.3 Hz

0.3 Hz

Accuracy/Linearity

Span/Div

Span/Div

2-4

>50Hz

<50

Hz

Within 5% of the selected Span/div Measured over the center 8 divi-

sions

Within 10% of the selected

div

Span/

Specification

Specification

Table

2-1:

Frequency Related Characteristics (Cont.)

Characteristic Performance Requirement Supplemental Information

Marker(s)

When activated, the marker is a

bright dot positioned by the CEN-

TER/MARKER FREQUENCY con­trol or the DATA ENTRY push but-

tons.

Normal Accuracy/Resolution Identical to Center Frequency ac- For the active trace.

curacy

A

MKR

Accuracy

±1%of

the total span For the active trace. AMKR acti-

vates a second marker at the posi­tion of the single marker on the
trace. Parentheses appear on the

marker display line indicating that

the delta mode is active. The dis­play shows the difference in fre­quency and amplitude. MKR
selects which marker is tuned.

A MKR Resolution

<

10% of

Span/Div.

1«*2

495 & 495P User Manual 2-5

Specification

Table 2-2: Amplitude Related Characteristics

Characteristic

Vertical Display Modes

Reference Level

(Top of the graticule)

Range

Log Mode

Linear Mode

Performance Requirement

Supplemental Information

10 dB/div, 2 dB/div, and Linear.
Any integer between 1 to 15 dB/div
can also be selected via the DATA

ENTRY Keypad.

From

-117

dBm to +50 dBm with

no reference offset; +50 dBm in-

cludes 20 dB of IF gain reduction

(+30 dBm is the maximum safe

input).
Alternate reference levels are:

• dBV (-130 dBVto +37

•

dBmV

• dBuV(-10dBuVto

39.6 nV/div to 2.8 V/div (1 W or

10

V

(-70 dBmV to

+97 dBmV)

+

157dBuV)

maximum safe input).

peak

dBV)

Steps

10dB/DivMode

2 dB/Div Mode

LIN

Mode

Set via DATA ENTRY

Keypad

10

dB for the coarse mode.

1

dB

for

the

FINE mode.

1 dB for the coarse mode.

0.25 dB for the FINE mode.

1 -2-5 sequence for coarse

mode.

1 dB equivalent steps for FINE

mode.

Steps correspond to the display

mode in coarse, except for 2

div

where steps are 1 dB.

dB/

In FINE mode:

• 1 dB when the mode is 5

div or more.

• 0.25 dB for display modes of

dB/

4 dB/div or less (referred to as

AAmode).

2-6

Specification