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

Table 2-2: Amplitude Related Characteristics (Cont.)

Specification

Characteristic

Marker(s)

Accuracy

Frequency Response and
Display Flatness

About the mid-point between
two extremes

Accuracy

Performance Requirement

±1.0

dB

Supplemental Information

Identical to REF LEVEL accuracy
plus cumulative error of display
scale. (Dependent on vertical posi-

tion.)

Frequency response is measured

with 10 dB of RF attenuation.

Response is affected by:

• InputVSWR

• Gain variation

• Mixer conversion

Dependent on the following char­acteristics:

• RF Attenuation Accuracy

• IF Gain Accuracy

• Resolution Bandwidth

• Display Mode

• Calibrator Accuracy

• Frequency Response

•

[Blue-SHIFT]

[CAL] routine

reduces error between resolu-

tion bandwidths at -20 dBm

REF LEVEL. Other REF LEV-

ELs may have larger errors.

• Ambient Temperature Change

(±0.15

cally ±0.05 dB/° C)

dB/°

C maximum, typi-

Display Dynamic Range

Accuracy

10dB/divMode

2 dB/div Mode

LIN

Mode

495 & 495P User Manual

±1.0

dB/10

dB to a maximum cu­mulative error of ±2.0 dB over
80 dB range

±0.4 dB/2 dB to a maximum cu-

mulative error of

±1.0

dB over

16 dB range

±5%

of

full scale

90 dB maximum for Log Modes

>12dB.

8 divisions for Linear Mode.

Maximum cumulative error of

±4.0 dB over 90 dB range.

2-7

Specification

Table 2-2: Amplitude Related Characteristics (Cont.)

Characteristic

RF Attenuator

Range

Accuracy DC to

1800

MHz

Gain Variation Between Resolution

Bandwidths

With Respect to 3 MHz Filter

Between Any Two Filters

IF

Gain

Range

Accuracy

Performance Requirement

Within 0.5

dB/10

dB to a maximum

of 1 dB over the 60 dB range

<±0.4dB
<0.8dB

Supplemental Information

0-60 dB in 10 dB steps.

Measured conditions:

• Measured at -20 dBm

•

MIN

• After CAL routine @ 25° C

87 dB of gain

DISTORTION mode

increase,

20 dB of

gain decrease (MIN NOISE and

REDUCED GAIN modes activated),
in

10dBand

1 dB steps.

1 dB Step

Decade Transitions

-19

to

-20

dBm

-29 to -30 dBm

-39 to -40 dBm

-49 to -50 dBm

-59 to -60 dBm

Maximum Deviation
Range

Over

the

<

0.2 dB/dB step to 0.5 dB/9 dB

steps except at the decade transi­tions

0.5 dB or less

±2dB

Maximum 1 dB cumulative error

over

10dB.

2-8

Specification

Table 2-2: Amplitude Related Characteristics (Cont.)

Specification

Characteristic Performance Requirement

Differential Amplitude

Measurement

Range

Accuracy

Supplemental Information

AA mode provides differential mea-

surements in 0.25 dB increments.

(This is not related to the

AMKR

mode.)
Maximum range of 57.75 dB de-

pendent on Reference Level when

the AA mode was activated.

Typical sensitivity 1 00

Hz to 1 kHz

is -75 dBm at 10 Hz Resolution

Bandwidth.
Equivalent maximum input noise

for each resolution bandwidth.

Measured at 25° C with:

• 0 dB RF attenuation (Min

OdB)

Atten

• Narrow Video Filter On

• Vertical Display 2

dB/div

(5

dB/

divinlOHzRBW)

• Digital Storage On

• Max Hold Off

•

Peak/Average

in Average

• 1 sec Time/Div

• Zero Span

• Input Terminated in 50

O

Spurious Responses

Residual

3rd Order

-

Intermediation

1

00

dBm

or less

Prod- -70 dBm or less

ucts

Harmonic Distortion -60 dBc or less

LO Emission -70 dBm or less

"Option

07 only.

495 & 495P User Manual

"Above 5 MHz.

"Above

10 MHz.

With no input signal.

From any two on-screen signals

within any frequency span.

In MIN DISTORTION mode.

Measured across the entire band,

with -30 dBm input and 0 dB at-

tenuation.

With 0 dB RF Attenuation.

2-9

Specification

Table

2-3:

Input Signal Characteristics

Characteristic

RF INPUT

Impedance

VSWRwith

>10dB

RF Attenuation

VSWR with 0 dB

RF Attenuation

Maximum Safe Input

(With 0 dB RF Attenuation)

1 dB Compression Point 0 dBm

(Minimum)

EXT REF IN

Frequency

1 , 2, 5, or

Performance Requirement

10

MHz ±5 PPM

Supplemental Information

Type N female connector. (See Op-

tion 07 characteristics at the end of

this section for supplemental spec­ifications concerning an additional
75 Q input.)

50

Q.

1.3:1 maximum (typically

2.0:1 maximum (typically

+30 dBm (1

75 W peak, pulse width of 1 us or

W)

continuous or

1.2:1).

1.9:1).

less with a maximum duty factor of

0.001 (attenuator limited).

Measured in
with no RF Attenuation.

MIN

NOISE

mode

Power

-

Waveshape

Input Impedance

HORIZ

| TRIG (rear panel)

Sweep Input Voltage Range

Trigger Input Voltage Range

Minimum

Maximum

DC + Peak AC

AC

1 5 dBm to + 1 5 dBm

At least

500 kHz

1.0

Vp_p from

15

Hz to

Sinewave, ECL, or
cycle of

AC=50 Q, DC=500

40%-60%.

TTL,

Q.

with a duty

DC coupled input for external hori-

zontal drive (selected by the EXT

position of the

TIME/DIV

control)
and AC coupled input for external
trigger signals (selected at other

positions of the

0 to +10 V (DC + Peak AC) for full-

TIME/DIV

control).

screen deflection.

Typically 1 MHz at

50V.

30

V

to 10 kHz, then derate lin-

RMS

early to 3.5

VRMS

at

1.5

100

V

.

peak

kHz and

above.

Pulse Width

2-10

0.1

|JS

minimum.

Specification

Table

2-3:

Input Signal Characteristics (Cont.)

Specification

Characteristic

MARKER | VIDEO (rear panel)

VIDEO Input Level

MARKER Input Level

ACCESSORY Connector (J104)

Pin1

Performance Requirement

Supplemental Information

External Video input or External

Video Marker input, switched by

pin 1

of

the ACCESSORIES con-

nector.

0 to +4 V for full-screen display

with pin 1

of

the ACCESSORIES

connector low.

0

to-10V.

Interfaces with TEKTRONIX

1405

TV Sideband Adapter.

25-pin connector (not RS-232 com­patible).

Provides bi-directional access to

the instrument bus. Also provides

External Video select. All lines are

TTL

compatible.

Maximum voltage on all lines is

±15

V.

External Video Select.
Low selects External VIDEO Input.
High (default) selects Video

MARKER Input.

Pin

2

Pin

3

Pin

4

Pin

5

Pins6-13

Pin

14

Pin

15

Pin

16

•Output

when Internally controlled

a

a

a

a

(pin 4 high)

and Input when externally controlled

Not used.

Not used.

Internal Control.

High (default) selects internal con-

trol. Instrument bus lines are out-

put at the ACCESSORIES connec-

tor.

Low selects External control.

Instrument bus lines at the AC-

CESSORIES connector accept

input from an external controller.

Chassis Ground.

Instrument Bus Address Lines
Instrument Bus Data Valid signal.

Instrument Bus Service Request

signal.

Instrument Bus Poll signal.

(pin

4 low).

7-0.

495 & 495P User Manual

2-11

Specification

Table

2-3:

Input Signal Characteristics (Cont.)

Characteristic

Pin

17

Pins

18-25

"Output

when internally controlled (pin 4 high) and input when externally controlled

a

Table

Characteristic

Calibrator (CAL OUT)

1st

LO and 2nd LO OUTPUTS

Performance Requirement

2-4:

Output Signal Characteristics

Performance Requirement

-20

dBm

±0.3

dB at 100 MHz

Supplemental Information

Data Bus Enable input signal for

external controller.

High

(unasserted)

disables exter-

nal data bus.
Low enables external data bus.

Instrument Bus Data lines 0-7.

Active when External Data Bus En­able (pin 17) is low.

(pin

4 low).

Supplemental Information

100

MHz

(phase locked to refer-

ence

oscillator).

Provide access to the output of the
respective local oscillators.

These ports must be terminated in

50 n at all times.

1stl_O

OUTPUT Power

2nd LO OUTPUT Power

VERT Output

HORIZ

PEN LIFT

10

MHz

Output

IF output

+6 dBm to +20

-10

dBm

dBm.

to+15 dBm.

Provides 0.5 V ±5% (open circuit)
of signal per division of video that
is above and below the center line.

Full range is -2.0 V to +2.0 V.

250

mV

maximum ripple. Source

impedance is approximately 1

kQ.

Provides 0.5 V/div (open circuit)
either side of center. Full range

-2.5 V to +2.5 V. Source imped-

ance is approximately 1 kQ.

TTL

compatible, nominal +5 Vto

lift plotter pen.

Output level is approximately

-5 dBm for a full-screen signal at

-30 dBm reference level. Nominal

impedance is approximately 50

Q

2-12

Specification

Table

2-4:

Output Signal Characteristics (Cont.)

Specification

Characteristic

IEEE STD 488 PORT

P-Version

Non-P Version (Plotter Output)

PROBE POWER (rear panel)

Outputs

Pin1

Pin

2

Pin

3

Pin

4

ACCESSORIES

(J104)

Performance Requirement

Supplemental Information

In accordance with IEEE 488-78
standard and Tektronix Codes and

Formats standard (version
Implemented as

SR1,

RL1,

Implemented as SH1,

SRO, RLO, PPO, DCO, DTO,

PP1,

SH1,

DC1,

AH1,

DT1,

AHO,

and CO.

81.1).

T5,

L3,

and CO.

T3, LO,

Provides operating voltages for ac-

tive probes.

+5 Vat 100

Ground.

-15V
+15

V at 100 mA maximum.

All inputs and outputs are listed in
Table
tics.

mA

maximum.

at 100 mA maximum.

2-3,

Input Signal Characteris-

Characteristic
Sweep

Sweep Time

Accuracy

Triggering

Internal Trigger Level

EXTERNAL Trigger Input Level

CRT Readout

Table

2-5:

General Characteristics

Performance Requirement

20

us/div

to 5 s/div in 1 -2-5 se-

quence

AUTO)

±5% over center 8

2 divisions or more

1.0

(10

s/div available in

Vp.p minimum

divisions

of signal

Supplemental Information

Triggered, auto, manual

, single

sweep, and external.

INTERNAL, EXTERNAL,

RUN,

and LINE.

EXTERNAL is

AC-coupled

FREE

(15

Hz

to 500 kHz). Maximum external

trigger input is 50 V (DC + Peak

AC).

Displays all parameters listed on

the CRT bezel, plus operating mes-

sages.

495 & 495P User Manual

2-73

Specification

Table 2-5: General Characteristics (Cont.)

Characteristic

Battery-Powered

Battery

Life

At +55° C

Ambient Temperature

At +25° C

Ambient Temperature

Lithium (Standard)
Silver (Option 39)

Temperature Range for

Retaining Data

Operating

Non-Operating

Memory

Performance Requirement

Supplemental Information

Instrument settings, macros, dis-

plays, and calibration offsets are

stored in battery-powered non-vol­atile RAM.

1 -2 years.

At least 5 years.

2-5 years.

-15° C to+55° C.

-30° Cto+85°C.

Characteristic

Line Frequency Range
Line Voltage Range

Line Fuse

115V

Nominal

230 V Nominal

Input

Power

Leakage Current

47-63

Hz

Else

Table

2-6:

Power Requirements

Performance Requirement

47 to 440 Hz

90

VAC

to

132

VAC

180

VAC

to

250

VAC

4A Fast-Blow
2A Slow-Blow

210

W maximum (3.2 A)

Supplemental Information

115 V nominal.

230 V nominal.

At

115V

and

60

Hz.

3.5

mA

maximum.

5 mA maximum.

2-74

Specification

Table 2-7: Environmental Characteristics

Specification

Characteristic

Meets

MIL-T-28800C,

Temperature

type III class 3, style C specifications as follows:

Operating

Non-Operating

Humidity

3

Operating
Non-Operating

Altitude

Operating

Non-Operating

Vibration, Operating (instrument secured to a

vibration platform during test)

Description

-15°Cto+55°C.

-62°Cto+85°C.

95% (+5%, -0%) relative humidity.

Five cycles (120 hours) in accordance with

Std-810D, Procedure 3 (modified).

15,000

feet, tested to

40,000

feet,

tested to 50,000 feet.

MIL-Std-810D,

25,000

feet.

Method 514 Procedure I (modified). Res-

MIL-

onant searches in all three axes from 5 Hz to 15 Hz at

0.060" displacement for 7 minutes,

0.040" displacement for 3 minutes, and 25 Hz to 55 Hz

15

Hz to 25 Hz at

at 0.020" displacement for 5 minutes (tested to 0.025").
Dwell for an additional

10

minutes in each axis at the
frequency of the major resonance or at 55 Hz if none
was found. Resonance is defined as twice the input

displacement. Total vibration time is 75 minutes.

Shock (Operating and Non-Operating)

Three guillotine-type shocks of 30 g,

11

ms duration each direction along each major axis;

total of 18 shocks. Tested to 50 g.

Transit Drop (free fall)

8 inch, one per each of six faces and eight corners

(instrument is tested and meets drop height of 12 in-

ches).

Electromagnetic Interference

(EMI)

Meets requirements described in

except as noted.
Test Method

Conducted Emissions

CE01-60Hzto15kHz

CE03-15kHzto50MHz

power leads

•After

storage at temperatures below -15° C, the instrument may not reset when power

instrument to warm up for at least

15

minutes, then turn POWER OFF for 5 seconds and back ON.

one-half

MIL-Std-461B

sine,

Part 4,

Remarks
1

kHz

to

15

kHz

only

15

kHz

to

50

kHz, relaxed

by 15 dB

is

first turned on. If this happens, allow the

495 & 495P User Manual

2-15

Specification

Table 2-7: Environmental Characteristics (Cont.)

Characteristic

Conducted Susceptibility

Radiated Emissions

Radiated Susceptibility

Description

Test Method

CS01

-30 Hz to 50 kHz

Remarks

Full limits

power leads

CS02-50 kHz to 400 MHz

Full limits

power leads

CS06-spike power leads Full limits

RE01

-30 Hz to 50 kHz

magnetic field

Relaxed by 10 dB for fun-

damental to

10th harmonic

of power line

Exceptioned, 30 kHz to

36kHz

RE02-14kHzto10GHz

RS01

-30 Hz to 50 kHz

RS02-Magnetic Induction To 5 A only, 60 Hz

RS03-14 kHz to

10

Full limit

Full limit

GHz Up to 1 GHz

Characteristic

Weight

Dimensions

Without Front

Cover,

Handle,

or Feet

With Front Cover, Feet, and Handle

Handle Folded Back Over the Instrument

Handle Fully Extended

Table

2-8:

Physical Requirements

Description

42

Ibs

Including cover and standard accessories, except
manuals.

See the Options Characteristics for alternate specifica-

tions.

6.9 x 12.87 x 19.65 inches
(175 x327 x

9.15 x 15.05 x 23.1 inches
(232

9.15 x 15.05 x 28.85 inches

(232 x 382 x 732.8 mm).

13 oz (19.3 kg) maximum.

499

mm).

x 382 x 587

mm).

2-76

Specification

Specification

2-78

Specification

This section describes spectrum analyzer unpacking, installation, power

requirements, storage information, and repackaging.

Unpacking and Initial

Inspection

Before unpacking the spectrum analyzer, inspect the shipping container for
signs of external damage. If the container is damaged, notify the carrier as

well as Tektronix, Inc. The shipping container contains the basic instrument

and its standard accessories. For a list of the standard accessories, refer to

Section 1, General Information. For ordering information, refer to the list

following the Replaceable Mechanical Parts list in the 495/P Service

al, Volume 2.

If the contents of the shipping container are incomplete, if there is mechani­cal damage or defect, or if the instrument does not meet operational check
requirements, contact your local Tektronix Field Office or representative.

Keep the shipping container if the instrument is to be stored or shipped to
Tektronix for service or repair. Refer to Storage and Repackaging for Ship-
ment later in this section.

Manu-

Functional Check

The instrument was inspected both mechanically and electrically before
shipment, and it should be free of mechanical damage and meet or exceed
all electrical specifications. Section 5, Instrument Check Out contains proce­dures to check functional or operational performance. Perform the functional

check procedure to verify that the instrument is operating properly. This
check is intended to satisfy the requirements for most receiving or incoming

inspections. A detailed electrical performance verification procedure in the
495/P Service Manual, Volume 1 provides a check of all specified perfor-

mance requirements, as listed in the Specification section.

495 & 495P User Manual

Air Flow Considerations

The instrument can be operated in any position that allows air flow into the

bottom and out the rear of the instrument. Feet on the four corners allow
ample clearance even if the instrument is stacked with other instruments.
The air is drawn in by a fan through the bottom and expelled out the back.
Avoid locating the instrument where paper, plastic, or any other material

might block the air intake.

3-1

Preparation for Use

Front Cover and Accessories Pouch

The front cover provides a dust-tight seal and a convenient place to store

accessories. Use the cover to protect the front panel when storing or trans-

porting the instrument. To remove the

back feet so the name on the handle is facing up and towards you. Pull
slightly out and up on the sides of the cover.

Attached to the inside of the cover is the accessories pouch. To open the

accessories pouch, pull up evenly on the flap.

cover,

stand the instrument on the two

Handle

You can position the handle of the spectrum analyzer at several angles to

serve as a tilt stand. To stack instruments, position the handle at the top rear

of the instrument. To change the handle position, press in at both pivot
points and rotate the handle to the desired position.

Position

WARNING

Removing or replacing the cabinet on the instrument can be haz­ardous. Only qualified service personnel should attempt to remove
the instrument cabinet.

Rack Adapter Kit

A field-installation kit is available to permit the spectrum analyzer to be rack

mounted in a standard 19-inch-wide rack on a non-tilting slide-out track. We
recommend fan-forced ventilation of the rack enclosure. If the rack-adapter

assembly is installed in an enclosed rack, a minimum depth of 25 inches

behind the front panel is recommended for proper air circulation. The rack
adapter kit comes complete with the
mounting hardware. Contact your local Tektronix Field Office or representa-

tive for additional information and ordering instructions.

slide-out

tracks and all necessary

Power Requirements

Changing the power input can be dangerous.

WARNING

Work safely

Know the intended power source
Set the instrument for the power source
Check the fuse for proper ratings

Use the power cord and plug intended for the power source

3-2 Preparation for Use

Preparation for Use

The 495/P operates from a
current-carrying conductors (neutral) at ground (earth) potential.

single-phase

power source that has one of its

Do

not
operate the 495/P from power sources where both current-carrying conduc­tors are isolated or above ground potential (such as
multi-phase system or across the legs of a

wire system). In this method of

operation,

110-220 V single-phase,

only the line conductor has over-

phase-to-phase

on a
three-

current (fuse) protection within the unit. Refer to the Safety Summary at the
front of this manual.

The AC power connector is a

three-wire,

polarized plug with the ground
(earth) lead connected directly to the instrument frame to provide electrical
shock protection. If the unit is connected to any other power source, con­nect the unit frame to an earth ground.

WARNING

Do not attempt to change the power input requirements.

ity

with safety procedures can result in personal injury. Refer all

power input changes to qualified service personnel. Refer to the

Unfamiliar-

Safety Summary at the front of this manual.

Operate the spectrum analyzer from either

voltage with a range of 90 to

132

or

180

115

VAC or 230 VAC nominal line

to 250 VAC, at 48 to 440 Hz. Power

and voltage requirements are printed on a back-panel plate mounted below

the power input jack. Refer power input changes to qualified service person-

nel. The 495/495P Service Volume 1 contains instructions to change the
input voltage range.

The international power cord and plug configurations are shown in Sec-

tion

7, Options.

Short Term (less than 90 days)

For short term storage, store the instrument in an environment that meets

the non-operating environmental specifications in Section 2 of this manual.

Long Term

For instrument storage of more than 90 days, retain the shipping container

to repackage the instrument. The battery in the instrument does not require

removal. Package the instrument in a vapor barrier bag with a drying agent
and store in a location that meets the non-operating environmental specifi­cations in Section 2 of this manual.

If you have any questions, contact your local Tektronix Field Office or
sentative.

repre-

495 & 495P User Manual

3-3

Preparation for Use

Repackaging for

Shipment

When the spectrum analyzer is to be shipped to a Tektronix Service Center
for service or repair, please attach a tag that provides the following informa­tion:

• Owner's name and address

• The name of the individual at your firm who can be contacted

• Complete instrument serial number

• Description of the service required.
If the original package is unfit for use or not available, use the following

repackaging information:

1.

To allow for

test strength of 375 pounds

are at least six inches more than the equipment dimensions (refer to

Physical Characteristics in Section 2).

2. Install the instrument front cover, and surround the instrument with

plastic sheeting to protect the finish.

3. Cushion the 495/P on all sides with packing material or plastic foam.

4. Seal the container with shipping tape or a heavy-duty, industrial stapler.

cushioning,

use a corrugated cardboard container with a

(140

kilograms) and inside dimensions that

Transit Case

A

high-impact,

spectrum analyzer to be frequently shipped between sites. A hard transit

case that meets these requirements and has space to hold the instrument's

standard accessories is provided as an optional accessory for the spectrum
analyzer. Contact your local Tektronix representative for additional informa­tion and ordering assistance.

ruggedized transit case is recommended if you require your

3-4

Preparation for Use

1 Controls, Connectors and Indicators

////

^

This section includes the descriptions of the

modes. It also covers the functions of the controls, selectors, indicators, and

connectors for the

through

greater detail in Section 5, Instrument Check Out.

Included with many of the descriptions are syntax diagrams that graphically

display the function. The ovals and circles indicate a literal element that

must be sent (i.e., push button pressed) exactly as shown. Boxes contain a

name for an element (for example, DATA ENTRY represents numbered push

buttons [0] through

arrows that connect the elements of the syntax diagrams show the possible

paths through the diagram. Parallel paths mean that one, and only one, of

the paths must be followed. A path around an element or group of elements

indicates an optional skip. Arrows indicate the direction that must be fol­lowed (usually the flow is to the right; but, if an element may be repeated, an

arrow returns from the right to the left of the

The following examples illustrate basic syntax diagram structure.

4-3

and

495/R

4-11

which are all shown and identified in Figures

through

[9],

4-16.

Some of the functions are described in

units terminators,

instrument's

[.],

and

[BACKSPACE]).

element).

main operating

4-1

The

Operating Modes

495 & 495P User Manual

When DATA ENTRY boxes are part of a command's syntax diagram, there
are numbers shown with the boxes. These numbers represent the valid

range available for that particular command.

Initial Entry Functions (Black-Labels)

Most of the 495P operating modes are selected by a single push button

press or control turn; i.e., [FREE RUN],

[MAX

HOLD],

with all Tektronix 49x-Series Spectrum Analyzers.

PEAK/AVERAGE.

TIME/DIV,

Generally, these selections are the same

[PULSE STRETCHER],

4-7

Controls, Connectors, and Indicators

Multiple
([SHIFT]

[Blue-SHIFT]

and two marker operating modes selected with multiple push button pres­ses. Press the [Blue-SHIFT] push button before selecting a blue-labeled
function; i.e.,

menu prompts appear on the screen to guide you.

[Green-SHIFT]

[Green-SHIFT]

[Green-SHIFT]

as [ASSIGN 1], [PEAK
appear on the CRT readout to guide you.

There are also additional marker functions that can be assigned to either

push button [ASSIGN

manner as the labeled functions. The MARKER MENU also has additional

marker functions that can be selected directly from the menu.

Push Button Sequence Functions

push buttons)

Functions

[PLOT],

[STORE

Functions — Most

multiple-push button presses are marker related. Press the
push button before selecting a green-labeled function such

1]

—There

DISP],

FIND].

For many of these functions, menu prompts

or [ASSIGN 2] and then selected in the same

are

many

general

[CAL]. For many of these

of the

operating

operating

modes

modes

functions,

selected

with

Terminating Multiple Push Button Sequences

A [SHIFT] multiple-push button sequence can be terminated at any time.

Push either the [Blue-SHIFT] or [Green-SHIFT] push button once to stop

the sequence and return the 495/P to the previous activity.

DATA ENTRY Functions (Orange Labels)

Some operations require the entry of numerical data; for example, to set
frequency or enter a number to select a choice from a menu. This will be as

part of a multiple-push button sequence. The screen will prompt you when a

number is required. Numbers are entered with the orange-labeled DATA

ENTRY push buttons. Numerical data is entered first, with a units terminator

entered

-20

last;

dBm.

for

example,

[1] [0]

[MHz]

for 10 MHz or [2] [0]

[-dBx]

for

Correcting Numerical Entry Errors

Use the [BACKSPACE] push button to correct errors in numerical data that

have been entered with the orange-labeled DATA ENTRY push buttons.

Each push button press backs the cursor up one space, erasing the number

in that location. You can then enter the correct numerical data and end the
sequence with a units push button.

4-2 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

4 COUNT — When this push button is pressed, the signal at the dot

position is counted with up to 1 Hz resolution at any FREQUENCY

SPAN/DIV

[COUNT

setting. The resolution is selected with

RESOLN].

The signal must be 20 dB or more above the

[Blue-SHIFT]

noise level and above a level that is 60 dB down from the REF-

ERENCE LEVEL setting.

5 AF — This push button allows measurement of the frequency differ-

ences. When pressed (lit), the frequency readout goes to zero. The
readout now shows only the

offset,

or deviation, from this reference as
the CENTER FREQUENCY is changed. The resolution of the readout
will be the less accurate of either the current CENTER FREQUENCY

resolution or the CENTER FREQUENCY resolution when [AF] was

activated. Do not confuse this push button with

[A

MKR],

which is described later in this section under Marker Func-

[Green-SHIFT]

tions.

6 [Blue-SHIFT] COUNT RESOLN — This push button sequence

allows you to select the desired counter resolution with the DATA

ENTRY push buttons. Terminate with one of the unit

[kHz], or

[Hz])

push buttons. The counter resolution will be truncated

([GHz],

[MHz],

to the decade that is less than or equal to the selected resolution.

7 CENTER/MARKER FREQUENCY — This control tunes the center

frequency or marker, if selected. Tuning of center frequency is done in

0.1 division increments, regardless of the selected FREQUENCY
SPAN/DIV setting. For marker frequency, tuning is either

0.1 division increments, depending on

how

fast

the control is turned.

O.OI,

0.033, or

In MAX SPAN mode, the center frequency is fixed, and only the fre-

quency dot is tuned. The tuning range in narrow spans is identical to

wide spans.

8

+STEP

mode

— When the instrument is in the Tune Center Frequency

([TUNE

CF/MKR] push button unlit), this push button increases

the CENTER FREQUENCY by steps. The step size is determined by

[Blue-SHIFT] [STEP ENTRY] or [Green-SHIFT] [STEP

SIZE].

[+STEP] later in this section under Marker Functions for alternate
operation.

9 -STEP — When the instrument is in the Tune Center Frequency

mode

([TUNE

the CENTER FREQUENCY by steps. The step size is determined by

[Blue-SHIFT] [STEP ENTRY] or [Green-SHIFT] [STEP

[-STEP]

CF/MKR] push button unlit), this push button increases

SIZE].

later

in

this

section

under

Marker

Functions

for

alternate

operation.

See

See

4-4

Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

10

[Blue-SHIFT]

FREQ — This push button sequence allows direct

entry of center or marker frequency to 1 Hz resolution (it will be dis-

played to 100 Hz) using the DATA ENTRY push buttons. If the center

frequency entered is not in the current frequency range, the nearest
frequency range that contains the frequency will be automatically

selected. The center frequency range that can be selected is 0 Hz to

1800 MHz. Values that are entered outside this range will be ignored.
Frequency digits that are entered from the DATA ENTRY push buttons

are terminated with one of the four unit push buttons

[kHz], or

11

POWER — This push-push switch turns the main power supply ON

(green light on) and OFF (in=ON, out=OFF). When power is switched

[Hz]).

([GHz],

off, the current instrument front-panel set-up is stored in memory

register 0 (see Using the Store and Recall Features in Section 5) so

this set-up can be easily recalled. Full RF Attenuation is switched in

when power is switched off to protect the

damage.

1st mixer from overload and

[MHz],

495 & 495P User Manual

4-5

Controls, Connectors, and Indicators

12

IDENT

— The

IDENT

mode allows identification of unwanted, internal­ly-generated mixing products, as is generally the case when power at
the input exceeds the reference level by >30 dB. This push button
causes every other trace to be displaced vertically. The

1st and 2

local oscillator frequencies shift so that real, or true, signals are not
displaced horizontally on alternate sweeps, while spurious signals can
be shifted. The FREQUENCY

13 AUTO RESOLN — When this function is on, RESOLUTION

SPAN/DIV

must be 50 kHz or less.

BANDWIDTH is automatically selected to maintain a calibrated display

for,

if possible, the selected FREQUENCY SPAN/DIV,

FILTER,

and VERTICAL DISPLAY modes. When the TIME/DIV control

TIME/DIV,

is in the AUTO position, RESOLUTION BANDWIDTH is selected as a
function of FREQUENCY SPAN/DIV only, and TIME/DIV is selected to

maintain a calibrated display at the highest sweep rate. The RESOLU-

TION BANDWIDTH control will not operate when AUTO RESOLN

mode is on (the message TO CHANGE RESOLUTION AUTO RESOLN

MUST BE OFF will appear on the screen).

4-6

Controls, Connectors, and Indicators

nd

VIDEO

Controls, Connectors, and Indicators

14 FREQUENCY

swept by the instrument. The range of this control is

100

MHz/Div.

CRT readout. Selection is in a 1 -2-5 sequence plus MAX SPAN
mode and

DIV

can also be entered with the
button sequence and the DATA ENTRY push buttons. The 495/P will
try to maintain a calibrated display if the
AUTO position or the [AUTO RESOLN] push button is active (lit).

When the FREQUENCY SPAN/DIV is in the MAX SPAN mode, the full

SPAN/DIV

— This control selects the frequency span

10

Hz/Div

The FREQUENCY SPAN/DIV setting is indicated by the

ZERO

SPAN mode, or time domain. FREQUENCY

[Blue-SHIFT]

TIME/DIV

[SPAN/DIV] push

control is in the

band is displayed. A dot near the top of the screen indicates the
CENTER FREQUENCY readout position on the span. This dot and the

center frequency position will be center screen when the FREQUENCY

SPAN/DIV is reduced from the MAX SPAN position. When the markers

are on, they show the frequency position, and the dot goes to center-

screen.

When the FREQUENCY SPAN/DIV is set to ZERO SPAN mode, the

495/P operates like a tunable receiver. The 495/P displays signals
within the resolution bandwidth in the time domain, with the CRT
reading out TIME/DIV instead of FREQUENCY SPAN/DIV.

to

SPAN/

15

RESOLUTION BANDWIDTH — This control selects the bandwidth of

the 495/P. Selected bandwidth is indicated on the CRT readout. The

bandwidth selections are 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz,

1 MHz, and 3 MHz. TIME/DIV is automatically selected to match the
selected bandwidth when the TIME/DIV control is in the AUTO posi-

tion.

16 [Blue-SHIFT] SPAN/DIV — This push button sequence allows direct

entry of FREQUENCY SPAN/DIV with two significant digits of resolu-

tion. The FREQUENCY SPAN/DIV range that can be selected is 10

Divto

170 MHz/Div. If a value outside the allowable range is entered,

the FREQUENCY SPAN/DIV will switch to 10 Hz if the selected value is

less than

than 170 MHz. Spans entered from the DATA ENTRY push buttons are

terminated with one of the four unit push buttons

[kHz],

10

Hz, or to MAX SPAN mode if the selected value is greater

([GHz],

or

[Hz]).

[MHz],

Hz/

495 & 495P User Manual

4-7

Controls, Connectors, and indicators

17

MAX SPAN — When activated, the 495/P sweeps the entire frequency

range. The position of the 495/P's CENTER FREQUENCY is shown

with a dot near the top of the screen. When this function is turned off,
the span returns to the previous FREQUENCY SPAN/DIV setting.

When the markers are on, they show the frequency position, and the

dot goes to center.

18

ZERO SPAN — This push button switches the span to zero for time

domain display. When ZERO SPAN mode is turned off, the FREQUEN­CY SPAN/DIV returns to its previous value.

19

UNCAL — This indicator lights when the display

amplitude

or frequen-

cy is no longer calibrated; e.g., the sweep rate is not compatible with

the FREQUENCY SPAN/DIV and RESOLUTION BANDWIDTH. Select a

slower sweep rate or larger RESOLUTION BANDWIDTH to return to

calibrated operation.

4-8

Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

20 TUNE

21

[Blue-SHIFT]

CF/MKR

pears on the trace of highest priority. The marker can be moved with

the CENTER/MARKER FREQUENCY control. When the push button

is pressed again, the marker remains and does not change its hori­zontal position. The CENTER/MARKER FREQUENCY control now
adjusts the center frequency.

— When this push button is lit, a single marker ap-

MKR OFF — This push button sequence turns the

marker(s) off.

22

[Green-SHIFT]

1*-MKR-»2

— This push button sequence alternate-

ly selects which marker will be tuned when [Green-SHIFT] [A MKR]

is on.

23

+STEP

[TUNE CF/MKR] push button is

marker frequency by steps (this function is limited to the edge of the
screen when not on an active trace). The step size is determined by

[Green-SHIFT] [STEP SIZE] or [Blue-SHIFT] [STEP
[+STEP] earlier in this section under Frequency for alternate opera-

tion.

— When the instrument is in the tune marker mode (the

lit),

this push button increases the

ENTRY].

See

495 & 495P User Manual 4-9

Controls, Connectors, and Indicators

24 -STEP — When the instrument is in the tune marker mode (the

[TUNE CF/MKR] push button is

lit),

this push button decreases the

marker frequency by steps (this function is limited to the edge of the
screen when not on an active trace). The step size is determined by

[Green-SHIFT] [STEP SIZE] or

[-STEP]

tion.

earlier in this section under Frequency tor alternate opera-

[Blue-SHIFT]

[STEP

ENTRY].

See

25 [Green-SHIFT] STEP SIZE — This push button sequence defines

the frequency step of the CENTER

FREQUENCY,

MARKER FREQUEN-

CY, or the DELTA MARKER FREQUENCY, whichever mode is active.

26 [Blue-SHIFT]

MKR

-»

CENTER — This

push button sequence

centers the signal at the active marker by setting the CENTER FRE-

QUENCY equal to the MARKER FREQUENCY (this function is not

available with a stored

27 [Green-SHIFT] dB/Hz — This push button sequence mathematically

trace).

figures the average noise power in a bandwidth at the current marker
position.

28 [Green-SHIFT] MKR

->

REF LVL — This push button sequence

changes the reference level of the top graticule to the present marker
amplitude (this function is not available with a stored trace).

29 [Green-SHIFT] SIGNAL TRACK — This push button sequence

automatically maintains tuning of a drifting signal within limits. While

this mode is active, SIGNAL TRACK will be displayed on the screen.

SIGNAL TRACK IDLE will be displayed when there is no signal above

the threshold. Excessive drift will disable this function. Select SET

SIGNAL THRESHOLD from the MARKER Menu to set the threshold.

30 [Green-SHIFT] ASSIGN 2 — This

push button sequence turns on

the assigned function.

31 [Green-SHIFT] ASSIGN 1 — This

push button sequence turns on

the assigned function.

32 [Green-SHIFT] BANDWIDTH — This push button sequence places

markers on a selected signal and displays the X dB bandwidth (select

ENTER BANDWIDTH NUMBER from the marker menu to set X). The

screen will display NO SIGNAL — BW IDLE when there is no signal at

the marker that meets threshold and bandwidth parameters. Set the

parameters by selecting SET SIGNAL THRESHOLD and ENTER
BANDWIDTH NUMBER after calling up the MARKER Menu each time.

4-70 Controls, Connectors, and Indicators

33

[Green-SHIFT]

Controls,

PEAK FIND — This push button sequence places

Connectors, and Indicators

the Primary marker at the peak of the highest on-screen signal.

[Green-SHIFT] [PEAK FIND] locates the left-most peak

center peak of a

cluster),

but it is not a signal processing command

with the built-in intelligence. Peak B would be selected from the cluster

in Figure 4-5A; peak A would be selected in Figure 4-5B because the

low point (B) would stop a search from continuing to the cluster (C).

(or

the

34 [Green-SHIFT]

allows you to set the start and stop frequencies directly from the delta

MKR

START STOP — This push button sequence

marker position (this function is not available with a stored trace).

[Green-SHIFT] [A MKR] must be on for this function to operate.

35 MARKER MENU — This push button calls up a menu display on the

screen that allows selection of one of the available marker commands

that are not permanently assigned to a front-panel push button.

RIGHT NEXT — This moves the Primary marker to the next visible

signal higher than the present marker frequency. If there is no signal to

the right of the Primary marker that meets threshold and signal type

parameters, one of the following messages will be displayed on the

screen (depending on whether CW, PULSE, or SPURS has been
selected as the signal type):

NO CW TO THE RIGHT ABOVE THRESHOLD
NO PULSE TO THE RIGHT ABOVE THRESHOLD
NO SPUR TO THE RIGHT ABOVE THRESHOLD

Select SET SIGNAL THRESHOLD and SET SIGNAL TYPE from the

Marker Menu to set the parameters.

495 & 495P User Manual

LEFT NEXT — This moves the Primary marker to the next visible

signal lower than the present marker frequency. If there is no signal to

the left of the Primary marker that meets threshold and signal type

parameters, one of the following messages will be displayed on the
screen (depending on whether CW, PULSE, or SPURS has been
selected as the signal type):

NO CW TO THE LEFT ABOVE THRESHOLD
NO PULSE TO THE LEFT ABOVE THRESHOLD
NO SPUR TO THE LEFT ABOVE THRESHOLD

Select SET SIGNAL THRESHOLD and SET SIGNAL TYPE from the
MARKER MENU to set the parameters.

4-11

Controls, Connectors, and Indicators

NEXT LOWER PEAK — This moves the Primary marker to the signal

with the next lower amplitude, either left or right of the present marker

position. If there is no signal lower than the Primary marker that meets
threshold and signal type parameters, one of the following messages
will be displayed on the screen (depending on whether CW, PULSE, or

SPURS has been selected as the signal type):

NO LOWER CW SIGNAL ABOVE THRESHOLD
NO LOWER PULSE SIGNAL ABOVE THRESHOLD
NO LOWER SPUR ABOVE THRESHOLD

Select SET SIGNAL THRESHOLD and SET SIGNAL TYPE from the
MARKER MENU to set the parameters.

NEXT HIGHER PEAK — This moves the Primary marker to the signal

with the next higher amplitude, either left or right of the present marker

position. If there is no signal higher than the Primary marker that
meets threshold and signal type parameters, one of the following
messages will be displayed on the screen (depending on whether CW,
PULSE, or SPURS has been selected as the signal type):

NO HIGHER CW SIGNAL ABOVE THRESHOLD
NO HIGHER PULSE SIGNAL ABOVE THRESHOLD
NO HIGHER SPUR ABOVE THRESHOLD

Select SET SIGNAL THRESHOLD and SET SIGNAL TYPE from the
MARKER MENU to set the parameters.

SET SIGNAL TYPE — This alters the marker functions to recognize
one of three signal types above the threshold (select SET SIGNAL
THRESHOLD from the MARKER MENU to set the threshold).

CW

— Identifies continuous wave signals and ignores spurious

signals and impulses.

PULSE — Identifies the peak of pulsed RF lobes for either line

(lines must be <2 minor divisions apart) or dense spectra.

SPURS — Identifies all signals.

Figure

4-4

is a signal enlarged to show how the 495/P locates the
signal peak with one of the signal processing functions. The signal
processing functions are RIGHT NEXT, LEFT
PEAK, NEXT HIGHER PEAK. The 495/P measures both the individual
left-most and right-most peaks of a signal. From this reading, the
495/P calculates the exact center of the signal. If this location is a
digital storage point, the marker is positioned here. If, as in Figure

NEXT,

NEXT LOWER

4-4,

the calculated center of the signal is not equal to the maximum digital
storage point, the marker is positioned on the closest point to the

center. At the end of this section are five illustrations (Figure 4-6
through Figure

4-10)

showing the use of this signal finding command.

4-72 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

SET SIGNAL THRESHOLD — This changes the minimum visible
signal level for the marker functions of Right Next, Left
Lower Peak, Next Higher

Peak,

Peak Find, Bandwidth Mode, and

Next,

Next

Signal Track. Select AUTO to automatically set the threshold above the

noise floor.

ASSIGN FUNCTION TO KEY — This displays a menu (ASSIGN

Menu) of additional marker functions that can be assigned to either
the

[Green-SHIFT]

[ASSIGN 1] or

[Green-SHIFT]

[ASSIGN 2]

push buttons. Call up HELP mode for the assigned push button to get

a description of the assigned function. The function will remain as-

signed to the push button, even with power off, until another function

is assigned. The ASSIGN Menu accesses the following functions as
well as RIGHT NEXT, LEFT NEXT, NEXT LOWER PEAK, and NEXT
HIGHER PEAK, which are described under MARKER MENU.

MOVE RIGHT X dB — This allows you to select the number of dB

to move the Primary marker while staying on the trace (horizontal

movement to the right). If there is no level to the right of the Prima-

ry marker that meets threshold, the message NO POINT TO THE
RIGHT TO MOVE TO will be displayed on the screen.

MOVE LEFT X dB — This allows you to select the number of dB

to move the Primary marker while staying on the trace (horizontal

movement to the

left).

If there is no level to the left of the Primary

marker that meets threshold, the message NO POINT TO THE
LEFT TO MOVE TO will be displayed on the screen.

495 & 495P User Manual

4-13

Controls, Connectors, and Indicators

FIND PEAK AND CENTER
peak of the highest on-screen signal (refer to the

—This

places the active marker at the

[Green-SHIFT]

[PEAK FIND] description later in this section). If a signal is pres-

ent,

the CENTER FREQUENCY is set equal to the marker frequen­cy. This centers the signal of interest (this is useful when reducing
FREQUENCY

SPAN/DIV

by several settings at once). If there is no

signal above the threshold, the message NO POINT FOUND

ABOVE THE THRESHOLD will be displayed on the screen and the

marker will not move.

ENTER BANDWIDTH NUMBER —This sets the number of dB below

the signal peak at which bandwidth will be calculated when in the

marker BANDWIDTH mode. The number is stored in memory.

GREEN-SHIFT

labeled functions can be directly selected. When GREEN-SHIFT

LOCK

—This

locks

[Green-SHIFT]

on so all green-

LOCK is on, the black-labeled functions associated with green-labeled

functions cannot be accessed. Blue-labeled functions operate normal-

ly. Press

[Green-SHIFT]

to exit this mode.

4-14

Controls,

Connectors, and Indicators

Controls, Connectors, and Indicators

36

[Green-SHIFT] A MKR

— This push button sequence is the

on-off

switch for the Delta Marker mode. When activated, a second marker
appears at the position of the single marker on the trace. The symbols

()

will appear on the screen on the marker frequency readout line to

indicate delta frequency and delta amplitude. To use Delta Marker,
press [TUNE
the trace using the CENTER/MARKER FREQUENCY control. Press

[Green-SHIFT] [A MKR] to activate the Delta Marker Mode, and

move one of the markers to the second point of interest. Press

[Green-SHIFT] [A MKR] again to turn delta markers off.

CF/MKR]

and set the marker to one point of interest on

Signal Finding

To the finding routine, a signal consists of a peak above threshold and two

points (one on each side of the peak) that are 3 dB below the peak. The

location of the signal is the highest amplitude point on the signal. Fig-

ures 4-6 through

selected from the MARKER Menu. All of the figures use the signal proces­sing function RIGHT NEXT. Any of the other signal processing functions

(LEFT NEXT, NEXT LOWER PEAK, NEXT HIGHER PEAK work in a similar

manner, according to their specific function. The minimum bandwidth criteria
for CW is defined as the two 3 dB down points that must be <5 kHz (1/2 a

RESOLUTION BANDWIDTH) apart.

4-10

illustrate the use of SET SIGNAL TYPE that can be

495 & 495P User Manual

4-15

Controls,

Connectors,

and Indicators

Figures 4-6, 4-7, and 4-8 — If CW is

selected,

the 495/P will not identify

any signal because none of the signals displayed meets the minimum
bandwidth criteria. If PULSE is selected, the signals labeled D, E, and F
would be identified because the other signals in the display are less than 2

minor divisions apart. If the signals were greater than 2 minor divisions
apart, PULSE would identify all labeled signals (A,

B,

C, etc.). If SPURS is

selected, all signals would be identified (A, B, C, etc.).

4-16

Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

495 & 495P User Manual

4-77

Controls, Connectors, and Indicators

4-78 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

Figure 4-9 — The NEXT RIGHT function begins at the left screen margin.

With this display, all signals are identified by CW, PULSE, and SPURS

modes because the signals meet the minimum bandwidth criteria (i.e., the

selections would be A, B, C, D, and E).

Figure

4-10

— In this example, assume that the threshold is -70

dBm.

If
CW is selected, signals B, E, F, and G would be identified. The other signals
do not meet the minimum bandwidth criteria, and would be ignored. If

PULSE is selected, signals A, B, D, E, F, and G would be identified. Signal C

would be skipped because it is located within 2 minor divisions of signal B.

The PULSE algorithm would not be able to identify signals B and C sepa-

rately. If SPURS is selected, all signals would be identified.

495 & 495P User Manual 4-79

Controls, Connectors, and Indicators

37 POSITION T ^ — These screwdriver adjustments position the dis-

play along the horizontal and vertical axes. The

[Blue-SHIFT]

[CAL]

push button sequence will guide you through the adjustment of these
controls. Refer to [Blue-SHIFT] [CAL] for additional information.

38 VIDEO FILTER WIDE — This push button reduces video bandwidth

and high-frequency components for display noise averaging. The

video bandwidth selected is approximately

RESOLUTION BANDWIDTH (1/100 for 3 MHz). Selecting [VIDEO

FILTER WIDE] cancels [VIDEO FILTER

1/30th of the selected

NARROW].

The filter value is

displayed in the lower readout.

4-20 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

39 VIDEO FILTER NARROW — This push button reduces video

bandwidth and high-frequency components for display noise averag­ing. The video bandwidth selected is approximately

selected RESOLUTION BANDWIDTH
EO FILTER NARROW] cancels [VIDEO FILTER

value is displayed in the lower readout.

40

[Blue-SHIFT]

REF LEVEL — This push button sequence allows

(1/30

for

1/300th of the

10

Hz).

WIDE].

Selecting [VID-

The filter

direct entry of reference level, with 1 dB resolution. The range is

+30

dBm

to

-117

dBm

(+50

dBm

if the MINIMUM NOISE and RE-

DUCED GAIN modes are selected). Values entered outside this range

are ignored (values will be in the selected units; dBm, dBV,

dBuV).

The

[+dBx]

or

[-dBx]

push buttons terminate the reference

dBmV,

level numbers entered.

or

41 [Blue-SHIFT]

entry of the desired amplitude display factor. The range is 1 to 15

Div in 1 dB increments. Numbers outside the allowable range will be

dB/DIV

— This push button sequence allows direct

dB/

ignored. Terminate the dB/div number entered with the [dB] push
button.

42 [Blue-SHIFT] CAL — This push button sequence starts a frequency

and reference level measurement procedure that uses the 495/P CAL

OUT signal. Messages on the screen guide the user through a proce-

dure to adjust the Vertical and Horizontal POSITION, and LOG and
AMPL CAL front panel adjustments. The 495/P then runs an automat-

ic frequency, bandwidth, and relative amplitude measurement routine
for the resolution bandwidth filters.

The frequency measuring routine adjusts CENTER FREQUENCY. It

measures the frequency of each resolution bandwidth filter to reduce
CENTER FREQUENCY variation when changing RESOLUTION BAND-

WIDTH settings. The relative amplitude measuring routine reduces

REFERENCE LEVEL variation when changing RESOLUTION BAND­WIDTH settings. To ensure that the 495/P meets frequency and ampli­tude performance characteristics, run these routines whenever the

instrument's surrounding temperature changes significantly.

Cal

factors that are used internally to correct for the errors measured by
this function are retained in memory when the instrument power is off.

To display these factors, press [Blue-SHIFT]

[LIN].

495

& 495P User Manual 4-21

Controls, Connectors, and Indicators

43

MIN

RF ATTEN dB — This control specifies the lowest value of input

attenuation that will be used when REFERENCE LEVEL is selected.
This allows operator-control to protect the front end of the 495/P

against overload or damage from excessive signal level into the 1

st

mixer. Actual attenuation is set according to the MIN RF ATTEN dB,

REFERENCE LEVEL, and [MIN

NOISE/MIN

DISTORTION] selec-

tions. It is displayed on the CRT readout. If the MIN RF ATTEN dB

setting is increased, the IF gain is automatically changed to maintain
the current REFERENCE LEVEL, if possible. The normal position is 0
to obtain the best noise level performance.

44 REFERENCE LEVEL — This control changes the reference level one

step for each stop. Automatic selection of the IF gain and RF Attenua-

tion provide for the best overall noise and distortion performance. In

the LOG VERTICAL DISPLAY mode (FINE mode off), the step size

equals the selected dB/Div factor, except for 2 dB/Div, where step size

is 1 dB. When FINE mode is on, the step size is 1 dB for scale factors

of 5 dB/Div or more and 0.25 dB for VERTICAL DISPLAY factors of less

than 5 dB/Div. When the display factor is less than 5 dB/Div and FINE

mode is on, the Delta A mode is

selected.

Refer to Section 6, Opera-

tion for a description of the Delta A mode.

45

[Blue-SHIFT]

allows the selection of reference level units to be dBm, dBV,

REF LEVEL UNITS — This push button sequence

dBmV,

or

dBuV.

46 AMPL CAL — This screwdriver adjustment, and the LOG CAL adjust-

ment, calibrates the vertical portion of the display. AMPL CAL adjusts

the display amplitude. Press [Blue-SHIFT] [CAL] to initiate a proce-

dure that will guide you through these adjustments. Refer to [Blue-

SHIFT] [CAL] for additional information.

47 LOG CAL — This screwdriver adjustment, and the AMPL CAL adjust-

ment, calibrates the vertical portion of the display. LOG CAL adjusts
the logarithmic gain in dB/Div. Press [Blue-SHIFT] [CAL] to initiate a

procedure that will guide you through these adjustments. Refer to

[Blue-SHIFT] [CAL] for additional information.

48 MIN NOISE/MIN DISTORTION

MIN NOISE — (push button lit) — In this mode, the noise level is

reduced by changing the RF Attenuation and IF gain used for a partic-

ular reference level. Both are reduced 10 dB so noise generated in the
IF stages is decreased. However, intermodulation distortion products

will increase. RF Attenuation must be at least 10 dB for this control to

have any effect.

4-22

MIN DISTORTION — (push button not lit) — In this mode, intermo-

dulation distortion products are minimized.

Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

49 FINE (A A IN <5

REFERENCE LEVEL control. When FINE mode is off, the step size

dB/DIV)

— This push button selects step size for the

equals the selected dB/Div factor, except for 2 dB/Div, where step size
is 1 dB. When FINE mode is on, the step size is 1 dB for scale factors

of 5 dB/Div or more and 0.25 dB for VERTICAL DISPLAY factors of less
than 5 dB/Div. When the display factor is less than 5 dB/Div and FINE

mode is on, the Delta A mode is selected.

In the Delta A mode the REFERENCE LEVEL readout goes to 0.00

and the REFERENCE LEVEL control steps in 0.25 dB increments.

dB,

These fine steps provide the means to make accurate relative ampli­tude measurements over a 48 dB measurement range. Refer to Delta
A mode operation in Section 6, Operation for more details.

50 PULSE STRETCHER — This push button causes the fall-time of pulse

signals to be increased so very narrow pulses can be seen. The effect

is most apparent for pulsed RF signals where pulse width is small

compared to one division of sweep time. Pulse stretcher operation

may be necessary for a digital storage display of such signals, to

ensure that the correct amplitude is displayed.

VERTICAL DISPLAY — These three push buttons select the vertical
display factors. The CRT readout indicates the selection. The vertical

display factor, in the LOG mode, can also be entered with the DATA
ENTRY push buttons.

51

LIN

— With this push button activated, a linear display between zero

volts (bottom graticule line) and the reference level (top graticule line),

scaled in volts/division, is selected (see the REFERENCE LEVEL

description).

NOTE

The sequence

[Blue-SHIFT]

[UN] displays a list of the factors

used to internally correct for frequency and amplitude errors. The

factors shown are as measured with the last

[Blue—SHIFT]

[CAL]

operation. If one of the factors could not be measured at the last

operation, the old value will be noted. This means that the previous-

ly measured value is used. If [ or ] appears next to the amplitude
calibration factor, it means that this filter's amplitude related to the
3 MHz filter is outside the range of correction (correction is set to
the limit). Press [Blue-SHIFT] to exit this display.

52 2 dB/DIV — This push button increases resolution so that each major

graticule division represents 2 dB. Display dynamic range is 16 dB.

53

10

dB/DIV — With this push button activated, the dynamic range of

the display is a calibrated 80 dB with each major graticule division

representing 10 dB. '

495 & 495P User Manual

4-23

Controls, Connectors, and Indicators

TRIGGERING

54

TIME/DIV

in a 1 -2-5 sequence in addition to AUTO, MNL, and EXT sweep
modes.

AUTO — (automatic) — This position allows the sweep rate to be

selected automatically to maintain a calibrated display for most FRE-

QUENCY

VERTICAL DISPLAY selections.

EXT — (external sweep) — This position allows the sweep circuit to be
driven by a signal applied to the rear-panel
connector. A voltage ramp of 0 to

horizontal (X) axis.

MNL—

manually swept with the MANUAL SCAN control.

— This control selects sweep rates from 5 s/Div to 20

SPAN/DIV,

RESOLUTION BANDWIDTH, VIDEO FILTER, and

HORIZJTRIG

+10

(Manual)

—This

V will sweep

position allows the spectrum or display to be

10

divisions of

us/Div

(EXT IN)

4-24 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

55 SINGLE SWEEP — When first pressed, this push button activates the

SINGLE-SWEEP mode and stops the current sweep. When pressed

again, the sweep trigger circuit is armed and the READY indicator is lit.

The sweep will run only after it receives a trigger signal. When SINGLE

SWEEP mode is selected, the TRIGGERING selection
RUN, INTernal, LINE, or
GERING selection to cancel SINGLE SWEEP mode.

56 READY — (only used in the SINGLE SWEEP mode) — This indicator

EXTernal)

is not changed. Select any TRIG-

(i.e.,

FREE

lights when the trigger circuit is armed and ready for a trigger signal. It
remains lit until the sweep ends.

57 MANUAL SCAN — With

TIME/DIV

set to the

MNL

position, rotate this

control to manually scan the spectrum.

58 EXT — This push button allows the sweep to be triggered by signals

that are applied through the rear-panel

nector. Other TRIGGERING selections are cancelled, including
SINGLE-SWEEP mode.

HORIZJTRIG

(EXT IN) con-

59 LINE — This push button allows a sample of the AC power line volt-

age to trigger the sweep. Other TRIGGERING selections are can-

celled, including SINGLE-SWEEP mode.

60

INT

— This push button allows the sweep to be triggered by any

signal at the left edge of the display that has an amplitude of 2.0 divi-

sions or more. Other TRIGGERING selections are cancelled, including
SINGLE-SWEEP mode.

61 FREE RUN — This push button allows the sweep to free run without

regard to trigger source. Other TRIGGERING selections are cancelled,
including SINGLE-SWEEP mode.

495 & 495P User Manual 4-25

Controls, Connectors, and Indicators

Store/Recall

62

[Blue-SHIFT]

___________

——»{

Blue

STORE

DISP

— This push button sequence starts a

multiple-push button sequence that stores either the A or B waveform
and its associated readout and marker(s) in a numbered

[8])

memory register. Information is held in memory while instrument

([0]

through

power is off. Messages displayed on the screen aid in completing the
multiple-push button sequence. After pressing [Blue-SHIFT]

[STORE

DISP],

a list of the stored displays is shown. Each stored

display is identified by its CENTER FREQUENCY. The number of digits

in a CENTER FREQUENCY in the menu list is an indication of the
FREQUENCY

SPAN/DIV

of that stored display (a larger number of

digits indicates a narrower span). This display includes a prompt
asking for the register number

([0]

through

[8])

into which the display

will be stored. Select the register from the DATA ENTRY push buttons.
When SAVE A mode is

whether the A or B waveform is to be

__________

SHIFT")—»{STORE

on,

there is an operator prompt that asks

_________________

DISP)—H

DATA

saved.

ENTRY

o-s

\-l

/—»<

VIEW

~A~)—v

>——»•

^—»•(

VIEW B

)—'

4-26 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

63

[Blue-SHIFT]

RECALL — This push button sequence starts a multi-

ple-push button sequence that recalls a selected waveform, with its
readout and

[8]).

The waveform is placed in either the A or B display for viewing.

marker(s)

from one of the memory registers

([0]

Information is held in memory while the instrument is off. After press-

ing [Blue-SHIFT] [STORE
shown. Each stored display is identified by its CENTER FREQUENCY

DISP],

a list of the stored displays is

This display includes a prompt asking for the register number

through
from the DATA ENTRY push buttons.

The readout for a recalled A waveform will only be displayed if VIEW B
and B-SAVE A modes are off and VIEW A mode is on. The readout
for a recalled B waveform will only be displayed if both VIEW B or

B-SAVE A modes are on and SINGLE SWEEP mode is selected. The
marker(s) will only be displayed if markers are turned on.

[8])

from which the display will be recalled. Select the register

through

([0]

SAVE A mode is activated to allow the separate display of the A or B
waveform. Remember to turn on SINGLE SWEEP mode before recal­ling a waveform to B to prevent overwrite by the sweep. The waveform
cannot be recalled into B when in MANUAL or EXTERNAL sweep
modes. Press [Blue-SHIFT] to exit during the sequence.

Digital

Storage — These push

buttons allow either

or

both

sections

of

memory to be selected to provide digital storage. When [VIEW A] and

[VIEW B] are activated, contents of both the A and B memories are dis-

played on the screen. Both sections are updated with each sweep.

64 B-SAVE A — When activated, the 495/P displays the difference

between the B waveform and the A waveform, and automatically turns

on SAVE A mode. The factory-set zero reference line is mid-screen.

Positive differences are displayed above this line and negative differ-

ences appear below the line. Refer any change in the position of the

zero reference line to authorized service personnel.

65 PEAK/AVERAGE — This control selects the vertical position (shown

on the screen by a horizontal line) at which digital storage switches
from peak detection to signal averaging. Signals displayed above the

cursor are peak detected. Signals displayed below the cursor are
digitally averaged.

495 & 495P User Manual 4-27

Controls, Connectors, and Indicators

66 MAX HOLD — This push button causes digital storage to retain the

maximum signal amplitude at every storage location (500 locations; or

1000

locations if SAVE A mode is

off).

If SAVE A mode is

on,

the A
waveform is not affected. Use [MAX HOLD] to measure frequency drift
or peak amplitude excursions of a signal.

67 SAVE A — This push button saves the A waveform and its readout.

The readout stored with the waveform is displayed if both [SAVE A]
and [VIEW A] are on, and [VIEW B] and [B-SAVE A] are off. If either

[VIEW B] or [B-SAVE A] is on, the readout reflects the current set-

tings. Turning SAVE A mode off cancels

B—SAVE

A mode if it is on. If

SAVE A mode is off and either [VIEW A] or [VIEW B] is on, both

waveforms will be displayed. The A waveform is not updated by the

sweep if SAVE A mode is on.

68 VIEW B — This push button causes the B waveform to be displayed.

69 VIEW A — This push button causes the A waveform to be displayed. If

SAVE A mode is on and only the A waveform is being viewed, the CRT

readout will show the settings when the A waveform was stored.

4-28 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

70 BACKSPACE — This push button backs the cursor up one space

each time it is pressed, erasing the number in that location. This
allows you to enter correct numerical data before finishing the se­quence with a units push button.

71

Green—SHIFT — This push button allows selection of the green-la-

beled front-panel push button functions. Press

time before selecting a green-lettered function.
cancels multiple push button sequence operations.

72

Blue-SHIFT

front-panel push button functions. Press [Blue-SHIFT] each time

before selecting a blue-lettered function. [Blue-SHIFT] also cancels
multiple push button sequence operations.

495 & 495P User Manual 4-29

— This push button allows selection of the blue-labeled

[Qreen-SHIFT]

[Green-SHIFT]

each

also

Controls, Connectors, and Indicators

73 RECALL SETTINGS — This push button recalls an instrument front-

panel setup from memory. The screen displays the CENTER FRE­QUENCY of each stored setup as an aid in identifying the contents of
each register (0-9). The time and minimum RF Attenuation settings

stay at the knob values. Select the desired register number, and the

front-panel controls automatically switch to that setup. The instrument

settings are automatically stored in register 0 when the 495/P is turned

off,

overwriting the settings previously stored there. To return to these

settings, press [RECALL SETTINGS]

74

[Blue-SHIFT]

STORE — This push button sequence allows a front-

[0].

panel setup to be stored in memory. Up to ten settings can be stored
in registers 0-9. The screen displays the CENTER FREQUENCY of

each setup as an aid in identifying the contents of each register. Select
the desired register, and the setup is stored. The instrument settings
are automatically stored in register 0 when the495/P is turned off,

overwriting the settings previously stored there.

75 [Blue-SHIFT] VIDEO FILTER WIDE — (Special Modes Menu; not

identified on the front panel)

—This

push button sequence brings up

a menu from which these special modes may be selected:

• [0] Tracking Generator Mode

•

[1]

Sideband Analyzer Mode

• [2] Reduced Gain Mode

• [3] EOS Corrections Mode

• [4]

Zero-Span

Time Mode

76 PLOT — (495 Only) This push button causes display information to

directly drive a plotter. The plotters that can be driven include the

following:

• Tektronix HC

lating the 4662)

• Hewlett Packard HP7470A, HP7475A, HP7580B, HP7585B, or

HP7486B

•

Gould

Press the [Blue-SHIFT] [SAVE A] push button sequence to select

the plotter type. Refer to Plotting

6310

100,

or

6320

4662 Option

the

01,

4662 Option

31,

or 4663 (emu-

Display in Section 6 for details.

4-30 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

77 Units — The units GHz, MHz, kHz, Hz, +dBx, -dBx, and dB are

available to complete a number-entry function from the front panel.

78

[Blue-SHIFT]

the front panel)

B-SAVE

—The

vertical position of the zero reference line for

A — (Plot

B-Save

A Offset; not identified on

the B-SAVE A display is set with an internal switch selection. Howev­er, when using the [PLOT] function, the position of zero reference for
the plot must be entered using this function. The range for the position

is 0 to 255 with

the DATA ENTRY push buttons when prompted by the CRT

125

representing center screen. Enter the position with

message,

and terminate with the [Hz] push button. The entered position is

stored in memory.

79

[Blue-SHIFT]

front panel)

SAVE A — (Select Plotter Type; not identified on the

—This

push button sequence displays the list of the

plotter types available for use with the [PLOT] push button (495 only)

and [Blue-SHIFT] [PLOT] push button sequence

(495Ponly).

the desired plotter type by choosing one of the menu items and enter-

ing the number on the DATA ENTRY push buttons. The choices are

listed below:

Select

• 0=Tektronix 4662 Option 01 or the 4663 in a one-pen setup

• 1 =Tektronix 4662 Option 31 or the 4663 in a two-pen setup

• 2=HP7470A

•

3=Tektronix

HC 100, HP7475A, HP7580B, HP7585B, or HP7586B,

Gould

Any plotter that is compatible with one of these can also be used. The

selected plotter type is stored in memory.

80 [Blue-SHIFT] MAX HOLD — (Instrument Errors; not identified on the

front panel)

—This

push button sequence displays all the detected

instrument errors; for use while troubleshooting.

81 DATA ENTRY — These orange push buttons are used to enter data

directly from the front panel when directed by a message on the CRT.
Numbers — The numbers [0] through [9] and a decimal point are

available to enter data from the front panel.

495 & 495P User Manual 4-31

Controls, Connectors, and Indicators

82

[Blue-SHIFT]

PULSE STRETCHER — (Diagnostic Aids; not identi-

fied on the front panel) — This push button sequence displays a menu

of all the available diagnostic aids for use while troubleshooting.

WARNING

MOST OF THE INFORMATION ACCESSED BY PRESSING THE

SEQUENCE [Blue-SHIFT] [PULSE STRETCHER] IS FOR QUAL-

IFIED SERVICE PERSONNEL ONLY.
PROCEDURES CAN RESULT IN PERSONAL INJURY. PERFORM
ONLY THE OPERATIONS THAT CAN BE COMPLETED FROM THE
INSTRUMENT FRONT PANEL. DO NOT ATTEMPT TO REMOVE THE
INSTRUMENT PANELS OR PERFORM ANY INTERNAL OPERA-

TIONS; CONTACT QUALIFIED SERVICE PERSONNEL.

UNFAMILIARITY

WITH SAFETY

83 [Blue-SHIFT] RESET — This push button sequence resets all front-

panel settings to their original condition as if power was just turned on.

84 [Blue-SHIFT] RUN/STOP — This push button sequence has three

functions, depending on the status of macros.

• If a macro is running, press [Blue-SHIFT] [RUN/STOP] to stop

the macro.

• If a macro is stopped, press [Blue-SHIFT] [RUN/STOP] to

restart the macro.

• If no macro is running or stopped, press [Blue-SHIFT]

[RUN/

STOP] to run the last macro that was executed.

85 [Blue-SHIFT] MACRO MENU — This push button sequence selects

a macro to be executed. The title of the macro is displayed next to the

macro number.

86 [Blue-SHIFT] BASELINE CLIP — This push button sequence clips,

or blanks, about one graticule division of the spectrum trace at the
baseline of the display. Use BASELINE CLIP mode to observe the
readout at the bottom of the screen or to eliminate the bright baseline

when photographing displays.

87 [Blue-SHIFT] READOUT — This push button turns CRT readout on

and off. The brightness is proportional to the trace brightness. This
sequence does not affect prompt or help messages.

88 GRAT

ILLUM

— This push button switches the graticule lights from

dim for low-light viewing to bright for photographing displays.

4-32 Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

89 HELP — This push button causes text to be displayed on the CRT to

explain the function of a selected front-panel control or push button.
Press the [HELP] push button; then press any push button or turn
most controls for an explanation of their function. Explanations are not

available for the

PEAK/AVERAGE,

INTENSITY, or MANUAL SCAN

controls. Press [HELP] again to exit this mode.

[Blue-SHIFT]

HELP — This push button sequence allows selection

of all explanations for functions called out on the front panel in blue.

[Blue-SHIFT] [HELP] only needs to be pressed once to begin the

selection (i.e., [Blue-SHIFT] [HELP], [REF

[READOUT]).

[Green-SHIFT]

Press [HELP] again to

HELP — This push button sequence allows selection

exit

this mode.

LEVEL],

[PLOT],

of all explanations for functions called out on the front panel in green.

[Green-SHIFT] [HELP] only needs to be pressed once to begin the
selection (i.e., [Green-SHIFT] [HELP],

FIND],

[MKR

START

STOP]).

Press [HELP] again to exit this mode.

[SIGNALTRACK],

For additional information on HELP mode, see Using the HELP Feature
in Section 6.

90

INTENSITY

— This control adjusts the brightness of the CRT trace,

readout, and text. Beam focus is automatically controlled.

[PEAK

495 & 495P User Manual 4-33

Controls, Connectors, and Indicators

91 RESET TO

LOCAL/REMOTE

— (495P Only) This push button is lit
when the 495P is in the remote state. While the instrument is remote,
the other front-panel controls are not active except for PEAK/AVER-

AGE,

INTENSITY, and MANUAL SCAN. Indicators still reflect the

current state of front-panel functions. This push button is not lit when

the 495P is in the local state. While the 495P is under local control, no

GPIB

messages are executed that would conflict with front-panel

controls or change the waveforms in digital storage. See Programming

Features in Section 6 for additional information.

92

[Blue-SHIFT]

PLOT — (495P Only) This push button sequence

causes display information to be sent over the GPIB port to directly
drive a plotter. The plotters that can be driven are listed below:

• Tektronix HC

lating the 4662)

• Hewlett Packard HP7470A, HP7475A, HP7580B,
HP7486B

4-34 Controls, Connectors, and Indicators

100,

4662 Option

01,

4662 Option

31,

or 4663 (emu-

HP7585B,

or

•

Gould

6310

or

Controls, Connectors, and Indicators

6320

Press the push button sequence

[Blue-SHIFT]

to select the plotter

type. Refer to Plotting The Display in Section 6 for details. This push

button also causes the 495P to update the

93

[Green-SHIFT]

SRQ — (495P Only) This push button sequence

GPIB

address.

sends a service request over the GPIB bus to the controller.

94 ADDRESSED — (495P Only) This indicator lights when the 495P is

addressed to either talk or listen. The characters T, L, and/or S appear

in the CRT readout to indicate talk, listen, and/or SRQ, respectively.

95

ZIA

RF INPUT 50 Q - This 50 Q coaxial input connector is for RF

signals to

1.8

GHz. If the input signal has a DC component, use a

blocking capacitor in line with the signal.

The maximum,

is +30

dBm

non-destructive

or 1 W.

input signal level to the input mixer

The maximum rating of the RF attenuator is +30 dBm (1 W average,

75 W peak pulse width 1
exceed 0.001). Burn-out occurs above 1 W. If

vated and the

exceeded if the signal level is increased to a full-screen display.
Under these conditions the input level will be +40 dBm. Reduce

the level of high-powered signals with external attenuators.

RFATTEN

ms

or less, with a duty cycle that does not

MIN

NOISE is acti-

is 60 dB, the +30 dBm rating will be

Input signals to the mixer must not contain any DC component.
Refer to Signal Application in Section 6.

96

ZJA

97 OUTPUT

RF INPUT 75 n — (Option 07 instruments only) — This connec-

tor provides calibrated 75 Q measurement capability.

(1ST

LO/2ND LO) — These connectors are the outputs of

the respective local oscillators. The connectors must be terminated

into 50 Q when they are not connected to an external device.

495 & 495P User Manual

4-35

Controls, Connectors, and Indicators

98 CAL OUT (Calibrator output) — This connector is the source of a

calibrated -20

dBm

(±0.3 dB), 100 MHz signal and a comb of fre­quency markers 100 MHz apart. This 100 MHz source is the instru­ment reference frequency.

For Option 07 instruments using the 50 Q input, the signal is the same
as the standard instrument. The signal is +20

using the 75 Q input.

dBmV

(±0.5 dB) when

99 Camera Power — This connector is the source of power for the

Tektronix cameras that have electrically-actuated shutters (either the

C-30BP

Option 01 or the C-9 Option 07 is

recommended).

Single-

sweep reset is not provided.

4-36

Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

100

PROBE POWER — This connector provides operating power for

active probe systems. This connector should be used only with com­patible probes or accessories specifically designed for use with this

power source.

101

HORIZJTRIG

the TRIGGERING and

(EXT IN) —

TIME/DIV

Horizontal

or triggering modes depend on

selections. In the EXTERNAL TRIG-

GERING mode, the connector is an AC coupled input for trigger

signals. Trigger amplitudes from 1.0 V to 50

mum pulse width or within the frequency range of 15

Vp.p,

with a 0.1 us mini-

Hz

to 1 MHz, are
required for triggering. When the TIME/DIV selection is EXT, the
connector is a DC coupled input for horizontal sweep voltages. Deflec-

tion sensitivity is 1 V/Div. A 0 to

+10

voltage will deflect the beam

across the screen from left to right.

102

MARKERJVIDEO

Option 42 only. See

connector interfaces the 495/P with a Tektronix

(EXT IN) — (Available on instruments without

110

MHz IF for Option 42 instruments.) This

1405

TV Adapter to

display an externally-generated marker.

495 & 495P User Manual 4-37

Controls, Connectors, and Indicators

In Option 42 instruments, the MARKER
changed to

110

MHz IF. It provides a

[VIDEO

110

(EXT IN) port is

MHz IF output with a

bandwidth greater than 4.5 MHz. External video signals used for

calibration may be injected into the PEN LIFT connector (see the PEN
LIFT description. This port is not compatible with a TV sideband
adapter.

103

HORIZ

signal. Full range is -2.5 V to +2.5 V. Source impedance is approxi-

mately 1

104

VERT (OUTPUT) — This connector provides access to the video

signal with 0.5 V for each division of displayed video that is above and
below the center line. Source impedance is approximately 1

(OUTPUT) — This connector supplies a 0.5 V/Div horizontal

kQ

NOTE

Both HORIZ and VERT output signals are driven from digital storage
if it is on. Both signals are driven from the 495/P sweep and video

amplifier stage if digital storage is off.

kQ.

105 PEN LIFT (OUTPUT) — This connector provides access to a

compatible signal to lift the pen of a chart recorder during 495/P

sweep retrace. This signal is always derived from the 495/P

regardless of the selection of the digital storage.

In Option 42 instruments, use this connector to input external video

signals if pin 1 of the ACCESSORIES connector is grounded (refer

any questions about this connection to qualified service personnel).

106

10

MHz IF (OUTPUT) — This connector provides access to the output

of the 10 MHz IF. The signal amplitude is about -30

dBm

for a full-

screen display.

107

EXTREFIN

reference signals, within the -15 dBm to

should be no greater than

offset, referenced to

a duty cycle symmetry of 40% to 60%, ECL or TTL.

(EXT IN)

—A

50 O input for 1, 2, 5, or 10 MHz external

+15

dBm level. Phase noise

-110

dBc in a 1 Hz bandwidth at 10 Hz

10

MHz. The input signal must be a sinewave with

TTL

sweep,

4-38

Controls, Connectors, and Indicators

Controls, Connectors, and Indicators

108

GPIB ADDRESS — (495P Only) These switches set the value of the

lower five bits of the instrument GPIB address. This value is the instru­ment's primary address. These switches also select the Talk Only and
Listen Only operating modes, and the message terminator for input

and output. Address 31

(11111)

logically disconnects the 495P from

the bus. Address 0 (00000) is reserved for Tektronix 4050-Series

controllers. If these switches are changed after the instrument is

already active, press [RESET TO LOCAL] or

[Blue-SHIFT]

[PLOT]

to cause the 495P to read them again.

109 IEEE STD 488 PORT (GPIB) — This connector interfaces the 495 to

the selected plotter, and interfaces the 495P to the GPIB bus. The
interface functions provided in the 495 are SH1, AHO, T3, LO, SRO,
RLO, PPO, DCO, DTO, and CO. The interface functions provided in the

495P are

SH1,

AH1,

T5, L3,

SR1,

RL1,

PP1,

DC1,

DT1,

and CO.

Details of how the switches are used in remote control are in the

Programmer manual.

110

J104

ACCESSORY — This connector provides bi-directional access

to the instrument bus. It is not RS 232 compatible. A

TTL

pin 1 selects EXTERNAL VIDEO. Video signals, which are applied to

rear-panel MARKER

(VIDEO,

are connected to the video path ahead

of the video filters.

495P

0 applied to

495 & 495P User Manual 4-39

Controls, Connectors, and Indicators

4-40

Controls, Connectors, and Indicators

This section includes the basic instrument check-out procedures and prepa-

ration for first-time use. An operational check is included for the front-panel

push buttons and controls, and some of the operating functions. No extra
equipment is required to perform these check-out procedures, and the
instrument cabinet does not need to be removed. Refer any additional

instrument check

out

to qualified service personnel.

Firmware Version

Readout

Error Message

Readout

When the instrument is first turned on, all of the front-panel LEDs will light

up. The front-panel processor firmware versions are then displayed on the

screen for approximately two seconds.

There are error messages to report the following failure conditions:

• Calibration failure

• Power supply failure

• Battery-operated RAM checksum error
Promptly report any error messages to qualified service personnel.
If the instrument detects an internal hardware failure, a failure report comes

on screen and remains for approximately 2 seconds. A status message then

appears and remains for as long as the failure exists. Press [HELP] to bring

error messages to the screen that explain the impact of the failure on instru-

ment operation.

If you attempt to recall a display or setting from a location where nothing is

stored, you will get a checksum error message even though there is not

really an error. This need not be reported to service personnel.

Frequency

Corrections

495 & 495P User Manual

If the oscillator frequency cannot be set due to a hardware
ment will attempt to set the oscillator frequency before each sweep. The
sweep
corrections, press

holdoff

Center frequency accuracy specifications will not be met in this

mode.

time will increase with each try. To disable the oscillator

[Blue-SHIFTJ

[10

NOTE

dB/DIV].

failure,

the instru-

5-7

Instrument Check Out

Press

[Blue-SHIFT]

routines. Another failure message will appear if the failure has not been

[10

dB/DIV]

again to enable the oscillator correction

corrected.

Preparation

for Use

^

ne

following

readout, display reference level, and bandwidth. Whenever a [SHIFT] push
button is required in this procedure to precede a multiple-push button
sequence, it is enclosed in brackets; i.e.

procedure

creates a display

and

calibrates

[Blue—SHIFT].

center

frequency

Initial Turn On

1.

Connect the spectrum analyzer power cord to an appropriate power

source (see Power Source and Power Requirements in Section 3 of this

manual) and push the [POWER] switch ON.

When [POWER] is switched ON (power-up), the processor runs a

memory and I/O test. If no processor system problems are found, the
power-up program will complete in approximately 7 seconds. The instru-

ment is now ready to operate.

Figure 5-1 shows the normal CRT readouts following the 7-second
power-up period. If a problem does exist within the instrument, a mes-

sage will appear on the screen. To bypass the failed test and attempt to

use the instrument, press the push button as directed in the error mes-

sage.

However,

performance may not be as specified.

5-2 Instrument Check Out

Instrument Check Out

The 495/P operating functions and modes will initialize to the following

power-up states.

READOUT

REFERENCE
CENTER
MARKER

SPAN/DIV

VERTICAL

RF

ATTEN

FREQ
RESOLUTION

TRIGGERING
AUTO

DIGITAL

MIN

NOISE/MIN

ALL

OTHER

...............................................

LEVEL

FREQUENCY

FREQUENCY

..............................................

DISPLAY....................................

.............................................

RANGE

.....................................

RESOLN

STORAGE

PUSH

...................................

...............................

................................

.........................................

BANDWIDTH

..........................................

......................

DISTORTION

BUTTONS

............................

VIEW

......................

................

A &

INACTIVE

ODBM

900MHZ

OMHZ

10DB/

0-1.8

3MHZ

FREE

VIEW

MIN

NOISE

OR OFF

ON

MAX

20DB

RUN

ON

B ON

2. Set the MIN RF ATTEN dB control to 0 (NORM) and the PEAK/AVER-

AGE control fully counterclockwise.

3. Set the

TIME/DIV

control to AUTO, REF LEVEL to -20

dBm,

and adjust

the INTENSITY for the desired brightness. Note that the RF ATTEN

readout is now ODB.

495 & 495P User Manual 5-3

Instrument Check Out

4. Apply the CAL OUT signal to the RF INPUT through a 50 Q cable. A dot
marker appears in the upper portion of the screen in the MAX frequency
span/division mode. This marker indicates the location on the display to
which the 495/P frequency is tuned. With a frequency readout of

OMHZ,

the marker is located in the top left portion of the screen.

5. Rotate the CENTER/MARKER FREQUENCY control and watch the dot

marker move across the display. Notice that the CENTER FREQUENCY

readout (top line) remains at 900

MHz,

and the MARKER FREQUENCY

readout (second line) changes according to the position of the marker

(dot).

Display Calibration

6. Harmonics of the
in Figure 5-2. To select

quence

[Blue-SHIFT]

7. Press the push button sequence [Blue-SHIFT]

[MHz] to change the SPAN/DIV to

100

MHz CAL OUT signal will be displayed as shown

100

MHz center frequency, press the key se-

[FREQ] [1] [0] [0]

[MHz].

[SPAN/DIV]

100

MHz. The dot marker is now

[1] [0] [0]

horizontally centered, and the 100 MHz CAL OUT signal is at center
screen.

8. If a message appears on the screen, press [FINE] to continue the
calibration or [Blue-SHIFT] to

exit

the routine.

When the [Blue-SHIFT] [CAL] push button sequence is pressed, the
instrument performs a center frequency and reference level calibration.
Prompts appear on the screen to guide the user through each procedure
step. The routine optimizes horizontal and vertical position, center frequen­cy, reference level, and dynamic range.

This calibration should be done at regular intervals so the instrument can

meet its center frequency and reference level accuracy performance specifi-

cations. It should also be performed any time the instrument ambient tem-

perature is substantially different from the last calibration. An explanation of
reference level accuracy with respect to ambient temperature is described in

Section 2, Specification.

5-4

To observe the results after a calibration is completed, press the push button
sequence [Blue-SHIFT]

[LIN].

A table appears on the screen that shows
the correction factor used to center the resolution bandwidth filters to pro­duce a calibrated center frequency. It also shows the correction that was
required to bring the amplitude of each filter within 0.4 dB of the 3 MHz filter.

1.

To begin the calibration procedure, press the push button sequence

[Blue-SHIFT]

[CAL].

2. A prompt message on the screen guides you through setting the four

front-panel adjustments: Vertical and Horizontal POSITION, and AMPL
and LOG CAL. This sets the absolute reference level for the 3 MHz

resolution bandwidth filter.

Instrument Check Out

Instrument Check Out

3. Next the instrument performs an automatic calibration that measures

and corrects for the absolute frequency and amplitude errors of the

filters (relative to 3 MHz). This takes approximately 60 seconds.

4. If a message appears on the screen, refer to Error Message Readout
earlier in this section. The correction factors are held in memory. Press
either [FINE] to continue calibration as instructed, or [SHIFT] to exit the
routine.

Functional or

Operational Check

This procedure uses minimum test equipment to check instrument operating
modes, functions, and basic performance. The procedure checks that the
instrument is operating properly. The internal calibrator and attenuator are
used as the source to check most of the operational characteristics. Since

both are very accurate, this check should satisfy most incoming inspection

or

pre-operational

ize you with the instrument operation. A detailed Performance Check that

verifies all performance requirements in Section 2, Specification is included

in the Service Manual, Volume

check-out requirements. This check will also help familiar-

1.

Equipment Required

The only external equipment used is an

the 50 Q coaxial cable, which are supplied as standard accessories.

N-male-to-BNC-female

adapter and

Preliminary Preparation

Perform the procedure described under Preparation for Use; then allow the
instrument to warm up for at least
check.

15

minutes before proceeding with this

Check Operation of Front-Panel Push Buttons and Controls

495 & 495P User Manual

This procedure checks the operation of all front-panel push buttons and

controls, and ensures that the buttons illuminate when the function is active.

The LED lights on the push button when the function is active. Lighted LEDs

also indicate the allowable selections for any of the multiple function push

buttons. For example, all DATA ENTRY push buttons light after

SHIFT]

or [Blue-SHIFT]

push button can enter data for that selection. Messages are displayed on

[FREQ],

[Blue-SHIFT]

[dB/DIV]

shift functions have been selected. Any lighted

[SPAN/DIV],

[Blue-SHIFT]

[Blue-

[REF

LEVEL],

the screen as guides to the entry sequence of these selections.

5-5

Instrument Check Out

Perform these steps before beginning this procedure:

1.

Connect the CAL OUT signal to the RF INPUT with the 50 Q cable and

BNC-to-N adapter.

2. Press

[Blue-SHIFT]

CENTER/MARKER
REFERENCE LEVEL

SPAN/DIV

VERTICAL

MIN

TIME/DIV

............................................

SCALE

RF

ATTEN

..............................................

FREQUENCY

......................................

dB

.................................. 0 (NORM)

[RESET];

.................................

then set the 495/P controls as follows:

......................

100MHZ

-20DBM
20KHZ

2DB/

AUTO

3. Press or change the following push buttons and controls and note their

effect on the operation.

INTENSITY — Rotate the control through its range and note the CRT beam

brightness change.

HELP — When this mode is activated, press or operate any push button
and most controls to produce a help message on the CRT that explains the
function of that push button or control. Help messages explain any error

message that may appear. Activate this mode, press various push buttons,

and observe the CRT message for each. Press the [HELP] push button

again to cancel. To get HELP messages for shifted functions, press the

desired [SHIFT] push button, press [HELP], then press the desired push

button.

GRAT

ILLUM

— When activated, the graticule is illuminated.

MARKER MENU — Press this push button to display a menu of available

marker commands that are not permanently assigned to a front-panel push

button.

TRIGGERING —To activate the TRIGGERING mode, press one of four

push buttons. The push button illuminates when in the active state. Press

any one of the push buttons to cancel or deactivate any other mode. Turn
VIEW A and VIEW B off to better observe the triggering effect.

• FREE RUN — In the active state, the trace free runs.

•

INT

— When active, the sweep is triggered when the signal or noise

level at the left edge is > 2.0 division.

1.

Use the CENTER/MARKER FREQUENCY control to tune one of the

100 MHz CAL OUT signals to the left edge of the display.

2. Adjust the REFERENCE LEVEL control so that the amplitude of the
signal is 2 or more divisions.

5-6 Instrument Check Out

Instrument Check Out

3. Press

4. Press [FREE

5. Adjust the REFERENCE LEVEL control so that the amplitude of the

[INT]

to activate

RUN].

INT

TRIGGERING to trigger the sweep.

signal is less than 2 divisions.

6. Press [INT] to activate INT TRIGGERING. The sweep is no longer
triggered.

• LINE — When active, the trace is triggered at power line frequency.
Press [LINE] and the sweep will be triggered.

• EXT — When this function is active, the trace runs only when an external
signal > 1.0

Vp.p is applied to the rear-panel EXT IN connector. Since

external test equipment is required to check this function, a check
cannot be made with this procedure.

SINGLE SWEEP — When this function is active, single sweep aborts the
current sweep. Press [SINGLE SWEEP] once to enter SINGLE SWEEP

mode. Press [SINGLE SWEEP] again to arm the sweep generator and light

the READY indicator. When triggering conditions are met after the circuit is

armed, the 495/P makes only one sweep. The indicator remains lit until the
sweep has run. The single sweep mode is cancelled when any TRIGGER-

ING push button is pressed. The effect of SINGLE SWEEP mode is more
apparent with VIEW A and VIEW B off.

1.

Press [VIEW A] and [VIEW B] to turn these displays off.

2. Press [FREE RUN] and set the

3. Press [SINGLE SWEEP] to abort the sweep.

4. Press [SINGLE SWEEP] again. The READY indicator lights and the

TIME/DIV

to 0.5 s.

sweep runs.

5. Press [FREE RUN] to cancel single sweep.

6. Return the TIME/DIV to AUTO.

TIME/DIV — This control selects sweep rate, manual scan, and external

sweep operation. In the MNL position, the MANUAL SCAN control moves

the CRT beam across the horizontal axis of the CRT graticule. In the EXT

position, a voltage of 0 to +10 V, applied to the rear-panel

connector, deflects the CRT beam across the full

VERTICAL DISPLAY — Display modes are activated by three push but-

10-division

HORIZJTRIG

screen.

tons. Press any of these push buttons to cancel any other mode.

•

10

dB/DIV

— When this push button is activated, the display is a cali-

brated 10 dB/division with an 80 dB dynamic range.

1.

Press [VIEW A] and [VIEW B] to turn these displays on.

495 & 495P User Manual

2. Set the REFERENCE LEVEL to -20

dBm.

5-7

Instrument Check Out

3. Press

4. Set the FREQUENCY

5. Use the CENTER/MARKER FREQUENCY control to tune the CAL

[10

dB/DIV].

SPAN/DIV

to 20 kHz.

OUT signal to center screen.

6. Use the REFERENCE LEVEL control to reduce the REFERENCE
LEVEL in 10 dB steps. The display steps in 1 division increments,

representing

7. Return the REFERENCE LEVEL readout to -20

• 2

dB/DIV

— When this push button is pressed, the display is a cali-

brated 2 dB/division with

1. Press [2

2. Use the REFERENCE LEVEL control to reduce the REFERENCE

LEVEL readout to -6 dBm. The display now steps

each two steps of the REFERENCE LEVEL control.

10

dB/DIV].

dB/division.

16

dB of dynamic range.

dBm.

1.0

division for

3. Return the REFERENCE LEVEL readout to -20 dBm.

•

LIN

— When this push button is pressed, the display is linear between
the reference level (top of the graticule) and zero volts (bottom of the
graticule), and the CRT VERTICAL DISPLAY reads out in volts/division.

1.

Press

PULSE STRETCHER — When this push button is

[LIN].

The Vertical Display readout changes to

pressed,

mV/division.

the fall-time of

video signals increases so narrow video pulses will show on the display.

1.

Select these front-panel control settings:

FREQUENCY
VERTICAL

TIME/DIV

VIEW

A and

2. Press [PULSE

SPAN/DIV

DISPLAY

...............................................

VIEW B ......................................

STRETCHER].

..............................

....................................

100MHZ

The signal peaks should increase in

10DB/

1 MS

OFF

brightness.

3. Press [PULSE STRETCHER] to turn off the PULSE STRETCHER mode.

4.

Set

the TIME/DIV to AUTO.

5. Press [VIEW A] and [VIEW B] to turn these displays on.

VIDEO FILTER

WIDE or NARROW (approximately

—Two

filters can be independently selected to provide

1/30th or

1/300lh of the resolution

bandwidth) filtering to reduce noise.

5-8

1.

Use the CENTER/MARKER FREQUENCY control to tune the 500 MHz

CAL OUT signal to center screen.

2. Change the FREQUENCY SPAN/DIV readout to 2 kHz.

Instrument Check Out

Instrument Check Out

495 & 495P User Manual 5-9

Instrument Check Out

3. Adjust the REFERENCE LEVEL as needed to view the noise floor.

4. Alternately press the [WIDE] and [NARROW] Video Filter push buttons.

The noise is reduced as the filter is turned on (see Figure 5-3). The

NARROW filter has a more pronounced effect on noise reduction. Note

the change in sweep rate when the

TIME/DIV

selector is in the AUTO

position.

5. Turn both Video Filters off.

DIGITAL STORAGE — Select either one or both of the A and B

waveforms from digital storage. The amplitude of a signal should remain

constant when digital storage is turned on (VIEW A or VIEW B activated).

The

PEAK/AVERAGE

control positions a cursor over the vertical window of

the screen. Noise and signal levels are averaged below the cursor and

peak-detected above the cursor.

• VIEW A — When this push button is pressed, the A waveform from

digital storage is displayed. With SAVE A mode off, the A waveform is

updated each sweep as the beam travels from left to right. With SAVE A

mode on, the waveform is not updated.

• VIEW B — When this push button is pressed, the B waveform is dis­played. When both VIEW A and VIEW B modes are active, the A and B
waveforms are interlaced and displayed. Both waveforms are updated
each sweep. Update of the A waveform depends on the state of SAVE A

mode.

• SAVE A — When SAVE A mode is

readout is
dated each sweep. If either VIEW B mode or B-SAVE A mode is on, the
readout reflects the current 495/P setup. The readout for the saved

saved.

In this mode, the data for the A waveform is not up-

activated,

the A waveform with its

waveform will be displayed any time SAVE A mode is on, and the VIEW

B and B-SAVE A modes are off.

1.

Press [SAVE A] to store the waveform in the A register.

2. Press [VIEW B] to turn it off.

3. Change the setting of the REFERENCE LEVEL control. The A

display will not change.

4. Press [SAVE A] to turn this mode off.

• MAX HOLD — When this push button is pressed, the maximum signal

amplitude at each memory location is stored. The waveform is updated

only when signal data is greater than that previously stored. To verify

operation, perform the following procedure:

5-10

1.

Return the REFERENCE LEVEL readout to -20 dBm.

2. Press [MAX HOLD] to turn this mode on.

3. Change the setting of the CENTER/MARKER FREQUENCY control.
The maximum level at each screen location will be retained.

4. Press [MAX HOLD] to turn this mode off.

Instrument Check Out

Instrument Check Out

• B-SAVE A — Press this push button to display the arithmetic difference

between an updated B waveform and a SAVE A waveform. The SAVE A

function is automatically activated when [B-SAVE A] is pressed.

The reference (zero difference) level is factory set at graticule center. The
position of this reference level can be changed by qualified service

personnel. Positive differences between the two displays appear above

this line and negative differences below the line.

1.

Press [VIEW A] and [VIEW B] to turn these displays on.

2. Press [SAVE A] to store the waveform in the A register.

3. Press [B-SAVE A] to view the difference between the B and SAVE A
waveforms.

4. Press [SAVE A] to turn this mode off.

•

PEAK/AVERAGE

— When digital storage is on, this control positions a
horizontal line, or cursor, anywhere within the graticule window. Signals
above the cursor are peak detected. Signals below the cursor are aver­aged by the digital storage. To verify operation, move the cursor within
the noise level. The noise amplitude will change as the cursor is posi­tioned.

IDENT

— When the identify function is turned on, the waveform is vertically
displaced on alternate sweeps. The frequencies of the 1st and 2nd local
oscillators are moved so that true signals are not displaced horizontally on
alternate sweeps while spurious signals are shifted significantly, or off
screen. The FREQUENCY SPAN/DIV setting must be 50 kHz or less before

IDENTIFY mode can be turned on. Refer to Using the Signal Identifier in

Section 6, Operation, for more details.

1.

Select these front-panel control settings:

CENTER/MARKER
FREQUENCY SPAN/DIV
REFERENCE LEVEL

VERTICAL

2. Press [IDENT] to turn the IDENTIFY mode on.

DISPLAY

3. There will be no horizontal displacement of the

FREQUENCY

................................

..................................

....................................

......................

100

MHz signal on

1500MHZ

50KHZ

-40DBM

10DB/

alternate sweeps. To help determine if the signal is true or spurious (see

Figure

5-4),

decrease the sweep rate or push [SAVE A] with both VIEW

A and VIEW B on, so a comparison can be made.

4. Press [IDENT] to turn the IDENTIFY mode off.

495 & 495P User Manual

5-77

Instrument Check Out

5-12

Instrument Check Out

Instrument Check Out

AUTO RESOLN — When this push button is pressed and FREQUENCY

SPAN/DIV

and

TIME/DIV

settings are changed, resolution bandwidth is

automatically selected by the processor to maintain a calibrated display. The

UNCAL indicator should not light over the FREQUENCY SPAN/DIV range if

the TIME/DIV selector is in the AUTO position.

1.

To check operation, change FREQUENCY SPAN/DIV or TIME/DIV

settings. The RESOLUTION BANDWIDTH will change automatically.

2. Return the TIME/DIV control to AUTO.

MAX SPAN — When

activated,

the span switches to maximum and the

495/P sweeps the full band. When deactivated, the FREQUENCY SPAN/DIV

returns to its previous setting.

ZERO SPAN — When activated, the FREQUENCY SPAN/DIV shifts to zero

for a time-domain display. When deactivated, the FREQUENCY SPAN/DIV

returns to its previous setting.

FREQUENCY SPAN/DIV — As this control is

SPAN/DIV changes between 0 and MAX. The display indicates the change.

rotated,

the FREQUENCY

RESOLUTION BANDWIDTH — As this control is rotated, the resolution

bandwidth changes in decade steps from 10 Hz to 1 MHz, and then to
3 MHz. The AUTO RESOLN mode must be off to change resolution band­width with the RESOLUTION BANDWIDTH control.

REFERENCE LEVEL — With 10
FINE mode off, the REFERENCE LEVEL readout steps in 10 dB increments

as the control is rotated. When FINE mode is

In the 2 dB/DIV mode, the steps are 1 dB with FINE mode off and 0.25 dB

with FINE mode on.

dB/DIV

VERTICAL DISPLAY active and

activated,

the steps are 1 dB.

495 & 495P User Manual

When the Vertical Display factor is 4 dB/div or less with FINE mode on, the

495/P

switches

LEVEL readout goes to 0.00 dB, then steps in 0.25 dB increments as the

REFERENCE LEVEL control is rotated.

1.

Set the

10 dB/DIV.

2. Rotate the REFERENCE LEVEL control counterclockwise to 40 dBm,
then clockwise to
changes in 10 dB increments.

3. Press

4. Change the setting of the REFERENCE LEVEL control. The REF­ERENCE LEVEL readout now steps in 1 dB increments.

to the delta A mode. In the delta A mode, the REFERENCE

MIN

RF

ATTEN

[FINE].

dB control to 0 dB and VERTICAL DISPLAY to

-110

dBm. The REFERENCE LEVEL readout

5-13

Instrument Check Out

5. Press

6. Rotate the REFERENCE LEVEL control. The REFERENCE LEVEL now

[Blue-SHIFT]

DATA ENTRY push buttons. The REFERENCE LEVEL readout goes to

0.00

dB.

[dB/DIV]

and enter 4 dB (press [4]

[dB])

with the

steps in 0.25 dB increments from the 0.00 dB reference.

MIN RF ATTEN dB

—This

control sets the minimum amount of RF attenu­ation in the signal path, regardless of the REFERENCE LEVEL control set­ting.

1.

To check

CENTER/MARKER

FREQUENCY
REFERENCE

VERTICAL

FINE....................................................

2. Set the MIN RF ATTEN dB selector to 20.

3. Change the REFERENCE LEVEL setting to -50

operation,

SPAN/DIV

LEVEL

DISPLAY

select these front-panel control settings:

FREQUENCY

...............................

..................................

....................................

.......................

dBm.

The RF ATTENU-

100MH2

500KHZ

-20DBM
10DB/

OFF

ATION readout will not go below 20 dB.

FINE

—When

Refer to the REFERENCE LEVEL check earlier in this section.

MIN

NOISE/MIN

activated, the REFERENCE LEVEL control steps decrease.

DISTORTION — This push button selects one of two

methods that select RF attenuator and IF gain. MIN NOISE mode (button
illuminated) reduces the noise level by reducing attenuation 10 dB and
decreasing IF gain 10 dB. MIN DISTORTION mode reduces

due to input mixer overload. To observe any

change,

the amount of RF

IM

distortion

ATTENUATION displayed by the CRT readout must be 10 dB higher than the

MIN RF ATTEN dB selector setting.

1.

To check operation, select these front-panel control settings:

CENTER/MARKER FREQUENCY
FREQUENCY
REFERENCE

VERTICAL

MIN RF

SPAN/DIV

LEVEL

DISPLAY

ATTEN

...............................

..................................

....................................

dB

.................................. 0 (NORM)

.......................

100MHZ

500KHZ

-20DBM

10DB/

2. The RF ATTENUATION readout will indicate 0 dB.

3. Press [MIN NOISE/MIN DISTORTION] to turn on MIN DISTORTION

mode. The noise floor will rise approximately

10

dB, and the RF AT-

TENUATION readout will change to 10 dB.

5-74

4. Press [MIN NOISE/MIN DISTORTION] to turn on MIN NOISE mode.

Instrument Check Out