Tektronix 7704a User manual

INSTRUCTION

-

MIAN

UAL

Tektronix,

Inc.

~

070-1402-00

e

P.O.

Box

500

@

Serial

Number

Beaverton,

Oregon

97005

-®

Phone:

644-0161

-@

Cables:

Tektronix

672

‘e

you

eS

ease

include

the

instrument

T

pe

Number

or

Part

4

972

by

Tektronix,

Inc.,

Beaverto

Oregon.

the

United

States

of

America.

All

rights

reserved.

Tektronix

COMMITTED

TO

EXCELLENCE

WARRANTY

NOTICE

THIS

WARRANTY

SUPERSEDES

ANY

OTHER

WARRANTY

PUBLISHED

FOR

THIS

PRODUCT

PRIOR

TO

JANUARY

1,

1980.

WARRANTY

Tektronix

warrants

that

this

product

is

free

from

defects

in

materials

and

workmanship.

The

warranty

period

is

one

(1)

year

from

the

date

of

shipment.

Tektronix

will,

at

its

option,

repair

or

replace

the

product

if

Tektronix

determines

it

is

defective

within

the

warranty

period

and

if

it

is

returned,

freight

prepaid,

to

a

service

center

designated

by

Tektronix.

Tektronix

is

not

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

from

connecting

the

product

to

incompatible

equipment;

c.

if

personnel

other

than

Tektronix

representatives

modify

the

hardware

or

software.

There

is

no

implied

warranty

of

fitness

for

a

particular

purpose.

Tektronix

is

not

liable

for

consequential

damages.

Warranty

2

SECTION

1

7704A

Operators

TABLE

OF

CONTENTS

OPERATING

INSTRUCTIONS

Preliminary

Information

Operating

Voltage

Operating

Temperature

Plug-In Units

Installation

Interchanging

Plug-ins

Controls

and

Connectors

Front-Panel

Color

Coding

Location

(Fig.

1-2A

&

B)

Operating

Checkout

(and

Familiarization)

Simplified

Operating

Instructions

Single-Trace

Displays

Dual-Trace

&

Dual-Sweep

Displays

Delayed

Sweep

Displays

X-Y

Displays

Detailed

Operating

Information

Intensity

—F

ocus—Astigmatism

Controls

BEAM

FINDER

Switch

CONTROL

ILLUM

Switch

Trace

Alignment

Graticule,

Light

Filter

Readout

System

Vertical

and

Horizontal

Mode

Logic

VERTICAL

MODE

Switch

HORIZONTAL

MODE

Switch

Vertical

Trace

Separation

TRIGGER

SOURCE

Switches

Intensity

Modulation

(Z-Axis)

CALIBRATOR

Output

Signal

Outputs

Probe

Power

Page

1-1

1-2

1-3,

1-4

15

1-8

1-9

19

1-9,

1-10

1-11

1-12

1-13

1-14

1-15

1-16

1-17

SECTION

1

OPERATING

INSTRUCTIONS

(cont)

Remote

Single-Sweep

Reset

Display

Photography

Applications

(Plug-In

Combinations)

Vertical

Amplifier

Plug-Ins

Time-Base

Plug-Ins

X-Y

Operation

Raster

Displays

Sampling

Displays

Special-Purpose

Plug-Ins

SECTION

2

SPECIFICATIONS

Electrical

Performance

Requirements

(7704A

Only)

Vertical

Deflection

System

Triggering

Horizontal

Deflection

System

Calibrator

Character

Readout

(Optional)

Signal

Buffer

(Optional)

Vertical

Signal

Output

Z-Axis

Input

+

Sawtooth

Output

+

Gate

Output

Remote

Reset

Input

(Single-Sweep)

Cathode

Ray

Tube

(CRT)

Power

Supply

Environmental

Characteristics

Physical

Characteristics

Instrument

Options

Standard

Accessories

System

Electrical

Characteristics

Page

1-17

1-18

1-19

2-1

2-2

2-3

24

2-4

24

25

nese?

SRT

7704A

Oscilloscope

System.

INTRODUCTION

The

TEKTRONIX

7704A

Oscilloscope

System

is

a

solid-state,

high

performance

instrument

designed

for

gen-

eral

applications.

(For

rise

time

and

bandwidth

specifica-

tions

of

oscilloscope

systems

using

the

7704A,

see

page

2-5.)

The

system

is

composed

of

two

individual

units,

the

A7704

Acquisition

Unit

and

the

D7704

Display

Unit.

The

A7704

Acquisition

Unit

has

four

plug-in

compart-

ments.

The

left

pair

of

plug-in

units

is

connected

to

the

vertical

system;

the

right

pair

is

connected

to

the

horizontal

system.

Electronic

switching

between

the

plug-ins

con-

nected

to

each

system

allows

a

dual-trace

vertical

display

and/or

a

dual-sweep

horizontal

display.

7704A

Operators

The

D7704

Display

Unit

features

a

CRT

with

small

spot

size

and

high

writing

rate.

In

addition

to

the

waveform,

the

CRT

can

also

display

alpha-numeric

information

from

the

plug-in

units,

such

as

deflection

factor,

sweep

rate

and

other

encoded

parameters.

Standard

graticule

size

is

8

X

10

cm.

DC

supplies

in

the

Acquisition

Unit

supply

power

for

the

entire

instrument.

These

supplies

are

regulated

to

assure

that

performance

is

not

affected

by

variations

in

line

voltage

and

frequency,

or

by

changes

in

load

due

to

the

varying

power

requirements

of

the

plug-in

units.

Section

1—7704A

Operators

OPERATING

INSTRUCTIONS

General

To

effectively

use

this

instrument,

the

operation

and

capabilities

of

the

instrument

must

be

known.

This

section

describes

the

operation

of

the

front-

and

rear-panel

controls

and

connectors

and

gives

general

operating

information.

PRELIMINARY

INFORMATION

Operating

Voltage

The

7704A

can

be

operated

from

either

a

115-volt

or

a

230-volt

nominal

line

voltage

source.

The

Line

Selector

assembly

on

the

rear

panel

converts

this

instrument

from

one

operating

voltage

to

the

other.

This

assembly

also

includes

line

fuses.

Use

the

following

procedure

to

obtain

correct

instrument

operation

from

the

line

voltage

available.

OLLI

IOS

?

CAUTION

This

instrument

is

designed

for

operation

from

a

power

source

with

its

neutral

at or

near

earth

(ground)

potential

with

a

separate

safety-earth

con-

ductor.

It

is

not

intended

for

operation

from

two

phases

of

a

multi-phase

system,

or

across

the

legs

of

a

single-phase,

three-wire

system.

1.

Disconnect

the

instrument

from

the

power

source.

2.

Loosen

the

two

captive

screws

which

hold

the

cover

onto

the

selector

assembly;

then

pull

to

remove

the

cover.

3.

To

convert

from

115-volts

to

230-volts

nominal

line

voltage,

or

vice

versa,

pull

out

the

Selector

switch

bar

(see

Fig. 1-1)

and

plug

it

back

into

the

remaining

hole.

Change

the

line-cord

power

plug

to

match

the

power-source

receptacle

or

use

a

115-

to

230-volt

adapter.

Power

Cord

Conductor

Identification

Conductor

Color

Alternate

Color

Ungrounded

(Line)

Brown

Black

Grounded

(Neutral) Blue

White

Grounding

(Earthing)

|Green-Yellow

|

Green-Yellow

REV...

C,

NOV...

1976

Indicator

Tab

Captive

Screws

Selector

Switch

bar

Fig.

1-1.

Line

Selector

assembly

on

rear

panel

(shown

with

cover

and

fuses

removed).

4.

Re-install

the

cover

and

tighten

the

captive

screws.

5.

Before

applying

power

to

the

instrument,

check

that

the

indicator

tab

on the

switch

bar

is

protruding

through

the

correct

hole

for

the

desired

line

voltage

range.

s

WII

I

TTI

TIS)

3

GA

UTION

This

instrument

may

be

damaged

if

operated

with

the

Line

Selector

assembly

set

to

incorrect

positions

for

the

line

voltage

applied.

The

7704A

is

designed

to

be

used

with

a

three-wire

AC

power

system.

If

the

three-

to

two-wire

adapter

is

used

to

connect

this

instrument

to

a

two-wire

AC power

system,

be

sure

to

connect

the

ground

lead

of

the

adapter

to

earth

(ground).

Failure

to

complete

the

ground

system

may

allow

the

chassis

of

this

instrument

to

be

elevated

above

ground

potential

and

pose

a

shock

hazard.

1-1

Operating

Instructions—7704A

Operators

Operating

Temperature

The

7704A

can

be

operated

where

the

ambient

air

temperature

is

between

O°C

and

+50°C.

This

instrument

can

be

stored

in

ambient

temperatures

between

—55°C

and

+75°C.

After

storage

at

temperatures

beyond

the

operating

limits,

allow

the

chassis

temperature

to

come

within

the

operating

limits

before

power

is

applied.

The

7704A

is

cooled

by

convection

air

flow

through

the

instrument.

Adequate

clearance

must

be

provided

on

all

sides

to

allow

heat

to

dissipate.

Do

not

block

or

restrict

the

air

flow

through

the

holes

in

the

cabinet.

Maintain

the

clearance

provided

by

the

feet

and

allow

about

two

inches

clearance

on

the

top,

sides

and

rear

(more

if

possible).

Operating

Position

A

bail-type

stand

mounted

on

the

bottom

of

the

instrument

permits

the

7704A

to

be

tilted

up

about

10°

for

convenient

viewing.

PLUG-IN

UNITS

General

The

7704A

accepts

up

to

four

TEKTRONIX

7-series

plug-in

units.

This

plug-in

feature

allows

a

variety

of

display

combinations

and

also

allows

selection

of

bandwidth,

sensitivity,

display

mode,

etc.

to

meet

the

measurement

requirements.

In

addition,

it

allows

the

oscilloscope

system

to

be

expanded

to

meet

future

measurement

requirements.

The

overall

capabilities

of

the

system

are

determined

by

the

characteristics

of

the

plug-ins selected.

Some

typical

combinations

are

given

under

““Applications’”

on

page

1-18.

along

with

simplified

instructions

for

setting

them

up.

For

information

on

other

plug-ins,

see

the

current

Tektronix,

Inc.

catalog.

Installation

of

Plug-In

Units

CAUTION

Plug-in

units

should

not

be

installed

or

removed

without

first

turning

the

instrument

power

off,

to

prevent

instrument

damage.

To

install

a

plug-in

unit

into

a

plug-in

compartment,

align

the

slots

in

the

top

and

bottom

of

the

plug-in

with

the

associated

guide

rails

in

the

plug-in

compartment.

Push

the

plug-in

unit

firmly

into

the

plug-in

compartment

until

it

locks

into

place.

To

remove

a

plug-in,

pull

the

release

latch

on

the

plug-in

unit

to

disengage

it

and

to

pull

the

unit

out

of

the

compartment.

1-2

All

the

plug-in

compartments

do

not

need

to

be

filled

to

operate

the

instrument;

the

only

plug-ins

needed

are

those

required

for

the

measurement

to

be

made.

At

environ-

mental

extremes,

excess

interference

may

be

radiated

into

the

instrument

through

the

open

plug-in

compartments.

Blank

plug-in

panels

are

available

from

Tektronix,

Inc.

to

cover

the

unused

compartments;

order

TEKTRONIX

Part

No.

016-0155-00.

Interchanging

Plug-ins

When

the

instrument

is

calibrated

as

directed

in

the

Service

Manual’s

Calibration

procedure,

the

vertical

and

horizontal

gains

are

normalized,

allowing

calibrated

plug-in

units

to

be

interchanged

from

one

compartment

to

another

without

recalibration.

However,

the

basic

calibration

of

the

individual

plug-in

units

should

be

checked

when

they

are

installed

in

this

system

to

verify

their

measurement

accuracy.

See

the

operating

instructions

section

of

the

plug-in

unit

instruction

manuals

for

verification

procedure.

CONTROLS

AND

CONNECTORS

The

major

controls

and

connectors

are

located

on

the

front

panel

of

the

instrument.

Several

auxiliary

functions

are

provided

on

the

rear

panel.

Figure

1-2

shows

the

front

and

rear

panels

and

provides

brief

descriptions

of

each

control

and

connector.

More

detailed

operating

information

is

given

under

‘Detailed

Operating

Information’

starting

on

page

1-9.

Front-Panel

Color

Coding

Portions

of

the

front-panel

of

the

7704A

and

its

plug-in

units

are

color-coded

as

follows

to

aid

in

operating

the

instrument:

RED

Identifies

the

nomenclature

and

controls

that

will

uncalibrate

the

instrument.

BLUE

Identifies

the

controls

affecting

the

CRT

display

mode.

GREEN

Identifies

all

trigger

controls.

Other

colors

such

as

gray,

orange,

yellow,

etc.

have

no

functional

assignments,

but

are

used

as

needed

to

indicate

the

relationship

between

the

appropriate

controls

and

connectors.

REV.

B,

NOV.

1977

Operating

Instructions—7704A

Operators

ASTIG

Screwdriver

adjust-

ment

to

obtain

a

well-defined

display.

Does

not

require

re-

adjustment

in

normal

use.

BEAM

FINDER

Compresses

and

defocuses

display

within

graticule

area

regardless

of

dis-

play

position

or

applied

signal.

TRACE

ROTATION

Screw-

driver

adjustment

to

align

trace

with

graticule.

FOCUS

Adjustment

for

opti-

mum

display

sharpness.

CALIBRATOR

Provides

cali-

brated

40mV-4V,

1kHz

square-wave

signals.

POWER

(PULL)

VERTICAL

MODE

Selects

_

lo

i -

/r¥0a

AOUUISTION

UST

&

vertical

plug-in

compart-

‘4

rica

na

ment(s)

providing

the

vertical

deflection

signal.

VERT

TRACE

SEPARATION

(B)

Vertically

positions

the

B

HORIZ

trace

with

respect

to

the

A

HORIZ

trace

(dual-

sweep

modes

only)

A

INTEN

Controls

brightness

of

the

trace

produced

by

the

A

HORIZ

plug-in.

A

TRIGGER

SOURCE

Selects

internal

trigger

source

for A

HORIZ

time

base.

INTENSITY

Controls

bright-

ness

of

the

display

(except

the

readout

portion).

«

READOUT

Controls

bright-

ness

of

the

readout

portion

of

the

CRT

display.

Turns

off

the

readout

system

when

in

the

CCW

detent

position.

GRAT

ILLUM

Controls

grati-

cule

illumination.

B

TRIGGER

SOURCE

Selects

internal

trigger

source

for

B

HORIZ

time

base.

B

INTEN

Controls

brightness

of

the

trace

produced

by

the

B

HORIZ

plug-in.

HORIZONTAL

MODE

Selects

horizontal

plug-in

compart-

ment(s)

providing

the

hori-

zontal

deflection

signal.

Fig.

1-2A.

Front-panel

controls

and

connectors.

1-3

Operating

Instructions—7704A

Operators

Z

AXIS

INPUT

Input

for

Z-

Axis

circuit

providing

inten-

sity

modulation

of

the

CRT.

VERT

SIG

Sample

of

vertical

signal

as

selected

by

B

TRIG-

GER

SOURCE

switch.

+

SAW

TOOTH

Sample

of

A

Sawtooth

or

B

Sawtooth

as

selected

by

an

internal

switch.

+

GATE

Square-wave

signal

as

selected

by

an

internal

switch:

A

Gate;

B

Gate;

or

A

Dely’d

Gate.

CONTROL

ILLUM

Controls

illumination

of

push-button

switches.

:

PROBE

POWER

Connectors

supplying

power

to

one

or

two

active

probes.

REMOTE

RESET

INPUT

Pro-

Line

Selector

Assembiy

Se-

vides

remote

single-sweep

reset

lects

the

nominal

line

voltage

when

Time

base

is

in

Single

(115

or

230

VAC).

Sweep

Mode.

Fig.

1-2B.

Rear-panel

controls

and

connectors.

OPERATING

CHECKOUT

The

following

procedure

checks

the

basic

operation

of

the

instrument.

It

may

also

be

used

for

familiarization

with

the

instrument

or

as

an

incoming

inspection.

Preliminary

1.

Set the

front-panel

controls

as

follows:

INTENSITY

Counterclockwise

A

INTEN

Midrange

FOCUS

Midrange

B

INTEN

Midrange

READOUT

OFF

GRAT

ILLUM

Counterclockwise

VERTICAL

MODE

LEFT

A

TRIGGER

SOURCE

VERT

MODE

HORIZONTAL

MODE

A

VERT

TRACE

SEPARATION

(B)

Midrange

B

TRIGGER

SOURCE

VERT

MODE

2.

Connect

the

instrument

to

a

power

source

that

meets

the

voltage

and

frequency

requirements

of

this

instrument.

If

the

available

line

voltage

is

outside

the

limits

of

the

Line

Selector

switch

(on

rear

panel),

see

‘“Operating

Voltage’’

in

this

section.

3.

Insert

7A-series

amplifier

units

into

both

vertical

compartments.

Insert

7B-series

time-base

units

into

both

horizontal

compartments.

4.

Pull

the

POWER

switch

to

ON.

Allow

several

minutes

warmup

so

the

instrument

can

reach

a

normal

operating

temperature

before

proceeding.

5.

Set

both

vertical

units

for

a

vertical

deflection

factor

of

two

volts/division

and

center

the

vertical

position

controls.

6.

Set

both

time-base

units

for

a

sweep

rate

of

0.5

millisecond/division

in

the

auto,

internal

trigger

mode.

7.

Advance

the

INTENSITY

control

until

the

trace

is

at

the

desired

viewing

level

(near

midrange).

8.

Connect

the

4V

CALIBRATOR

signal

to

the

input

connector

of

the

LEFT

VERT

unit

with

the

special

patch

cord

(supplied

accessory).

®

Operating

Instructions—7704A

Operators

9.

Adjust

the

FOCUS

control

for

a

well-defined

display

over

the

entire

trace

length.

(If

focused

display

cannot

be

obtained,

see

‘‘Display

Focus’’

in

this

section.)

10.

Disconnect

the

input

signal

and

position

the

trace

(with

the

LEFT

VERT

unit

position control)

on the

center

horizontal

line

of

the

graticule.

If

the

trace

is

not

parallel

with

the

center

horizontal

line,

re-adjust

the

TRACE

ROTATION

control.

11.

Rotate

the

GRAT

ILLUM

control

throughout

its

range

and

notice

that

the

graticule

lines

are

illuminated

as

the

control

is

turned

clockwise

(most

obvious

with

tinted

filter

installed).

Set

control

so

graticule

lines

are

illuminated

as

desired.

Vertical

and

Horizontal

Gain

Check

12.

Connect

the

4V

CALIBRATOR

pin-jack

to

the

input

connector

of

either

vertical unit

using

the

BNC

to

pin-jack

cable

(supplied

accessory)

and

BNC

T

connector.

Connect

the

output

of

the

BNC

T

connector

to

the

input

of

the

other

vertical

unit

with

a

BNC

cable.

The

display

should

be

two

divisions

in

amplitude

with

five

complete

cycles

shown

horizontally.

An

incorrect

display

indicates

that

the

plug-ins

need

to

be

recalibrated.

See

the

instruction

manual

of

the

applicable

plug-in

unit

for

adjustment

information.

Vertical

and

Horizontal

Modes

13.

Notice

that

the

POSITION

controls

of

only

the

LEFT

VERT

unit

and

the

A

HORIZ

time-base

unit

have

any

effect

on

the

displayed

trace.

Position

the

start

of

the

trace

to

the

left

edge

of

the

graticule

with

the A

HORIZ

time-base

unit

POSITION

control.

Move

the

trace

to

the

upper

half

of

the

graticule

with

the

LEFT

VERT

unit

POSITION

control.

14.

Press

the

RIGHT

button

of

the

VERTICAL

MODE

switch.

Also

press

the

B

button

of

the

HORIZONTAL

MODE

switch.

Notice

that

the

position

controls

of

only

the

RIGHT

VERT

unit

and

the

B

HORIZ

time-base

unit

have

any

effect

on the

displayed

trace.

15.

Position

the

start

of

the

trace

to

the

left

edge

of

the

graticule

with

the

B

HORIZ

time-base

POSITION

control

and

move

the

display

to

the

bottom

half

of

the

graticule

with

the

RIGHT

VERT

unit

POSITION

control.

1-5

Operating

Instructions—7704A

Operators

16.

CHOP

VERTICAL

MODE.

Press

the

CHOP

button

of

the

VERTICAL

MODE

switch.

Turn

the

B

HORIZ

time-base

unit

TIME/DIV

switch

throughout

its

range.

Notice

that

a

dual-trace

display

is

present

at

all

sweep

rates

with

both

vertical

units

being

displayed

on

each

sweep

on

a

time-sharing

basis.

17.

ALT

VERTICAL

MODE.

Press

the

ALT

button

of

the

VERTICAL

MODE

switch.

Note

that

two

traces

are

displayed

on

the

CRT.

The

top

trace

is

produced

by

the

LEFT

VERT

unit,

the

bottom

trace

is

produced

by

the

RIGHT

VERT

unit,

and

the

sweep

for

both

traces

is

produced

by

the

B

HORIZ

time-base

unit.

Reduce

the

sweep

rate

of

the

B

HORIZ

time-base

unit

to

50

milliseconds/division.

Notice

that

the

display

alternates

between

the

left

and

right

vertical

plug-ins

after

each

sweep.

Turn

the

B

HORIZ

TIME/DIV

switch

throughout

its

range.

Notice

that

the

display

alternates

between

vertical

units

at

all

sweep

rates.

Return

the

B

HORIZ

time-base

unit

TIME/DIV

switch

to

0.5

millisecond/division.

18.

ADD

VERTICAL

MODE.

Press

the

ADD

button

of

the

VERTICAL

MODE

switch.

The

display

should

be

four

divisions

in

amplitude.

Notice

that

the

position

control

of

either

vertical

unit

moves

the

display.

Press

the

LEFT

button

of

the

VERTICAL

MODE

switch.

19.

CHOP

HORIZ

MODE.

Press

the

CHOP

button

of

the

HORIZONTAL

MODE

switch.

Turn

the

TIME/DIV

switches

of

both

time-base

units

throughout

their

range.

Notice

that

two

traces

are

displayed

on

the

CRT

at

all

sweep

rates.

Also

notice

that

when

both

time-base

units

are

set

to

a

slow

sweep

rate

(50

milliseconds/division

or

slower),

both

traces

are

visible

on

the

CRT

at

the

same

time.

20.

ALT

HORIZ

MODE.

Press

the

ALT

button

of

the

HORIZONTAL

MODE

switch.

Two

traces

should

be

present

on

the

CRT.

Adjust

the

VERT

TRACE

SEPARATION

(B)

control

to

move

the

B

trace

to

the

bottom

of

the

graticule

area.

NOTE

Both

horizontal

plug-ins

must

run

individually

if

the

7704A

is

to

operate

in

ALT

Horiz.

Mode.

Turn

the

TIME/DIV

switches

of

both

time-base

units

throughout

their

range.

Notice

that

each

time-base

unit

controls

one

of

the

traces

independent

of

the

other

time-base

unit.

Also

notice

that

when

one

of

the

time-base

units

is

set

to

a

slow

sweep

rate

(below

about

50

milliseconds/division),

sweep

alternation

is

evident,

with

only

one

of

the

traces

present

on

the

CRT

at

a

time.

1-6

Return

the

sweep

rates

of

both

time-base

units

to

0.5

millisecond/division.

Adjust

the

A

INTENSITY

control.

Notice

that

it

changes

the

intensity

of

the

trace

produced

by

the

A

HORIZ

time-base

unit

only.

Likewise,

the

B

INTENSITY

control

changes

the

intensity

of

the

trace

produced

by

the

B

HORIZ

time-base

unit

only.

Return

both

intensity

controls

to

the

desired

level.

21.

CHOP

HORIZ-CHOP

VERT

MODE.

Change

the

input

signal

from

the

CALIBRATOR

to

0.4

V.

Press

the

CHOP

buttons

of

the

VERTICAL

MODE

and

HORIZONTAL

MODE

switches.

Four

traces

should

be

displayed

on

the

CRT.

If

not,

adjust

the

POSITION

controls

of

the

vertical

units

and

the

VERT

TRACE

SEPARATION

(B)

control

to

position

the

four

traces

onto

the

viewing

area.

Adjust

the

POSITION

controls

of

the

plug-in

units

to

identify

which

traces

are

produced

from

each

of

the

plug-in

units

(if

vertical units

have

the

identify

feature,

it

can

be

used

to

identify

the

traces).

Also,

set

one

of

the

time-base

units

to

a

sweep

rate

of

one

millisecond/

division.

Notice

that

the

vertical

deflection

produced

by

the

LEFT

VERT

unit

is

displayed

at

the

sweep

rate

of

both

the

A

HORIZ

and

B

HORIZ

time-base

units.

The

vertical

deflection

produced

by

the

RIGHT

VERT

plug-in

unit

is

also

displayed

at

the

sweep

rate

of

both

the A

HORIZ

and

B

HORIZ

time-base

units.

22.

ALT

HORIZ-CHOP

VERT

MODE.

Press

the

ALT

button

of

the

HORIZONTAL

MODE

switch.

Notice

that

the

display

is

very

similar

to

the

display

obtained

in

the

The

main

difference

in

this

display

is

that the

sweeps

are

produced

alternately

by

the

time-base

units

(noticeable

only

at

slow

sweep

rates).

23.

INDEPENDENT-PAIRS.

Press

the

ALT

button

of

the

VERTICAL

MODE

switch.

Connect

the

BNC

to

pin-jack

cable

to

the

0.4V

calibrator

output.

Notice

that

only

two

traces

are

displayed

on

the

CRT.

Also

notice

that

one

of

the

traces

is

produced

by

the

left

vertical

unit

at

the

sweep

rate

of

the

BHORIZ

time-base

unit

and

the

other

by

the

right

vertical

unit

at

the

sweep

rate

of

the

A

HORIZ

time-base

unit.

This

feature

is

called

independent-pairs

operation,

and

is

obtained

only

when

the

VERTICAL

MODE

switch

is

in

the

ALT

position

and

the

HORI-

ZONTAL

MODE

switch

is

in

either

the

ALT

or

the

CHOP

position.

Triggering

24.

Press

the

LEFT

button

of

the

VERTICAL

MODE

switch

and

the

A

button

of

the

HORIZONTAL

MODE

switch.

Center

the

display

on

the

CRT

with

the

LEFT

VERT

unit

POSITION

control.

Disconnect

the

input

signal

from

the

right

vertical

unit

input

connector.

Sequentially

press

all

of

the

VERTICAL

MODE

switch

buttons.

Notice

that

a

stable

display

is

obtained

in

all

positions

of

the

VERTICAL

MODE

switch

(straight

line

in

RIGHT

position).

25.

Press

the

LEFT

VERT

button

of

the

A

TRIGGER

SOURCE

switch.

Again,

sequentially

press

all

of

the

VERTICAL

MODE

buttons.

Notice

that

the

display

is

again

stable

in

all

positions.

26.

Press

the

RIGHT

VERT

button

of

the

A

TRIGGER

SOURCE

switch.

Sequentially

press

all

the

VERTICAL

MODE

switch

buttons

and

notice

that

a

stable

display

cannot

be

obtained

in

any

position.

This

is

because

there

is

no

input

signal

connected

to

the

right

vertical

unit.

Return

the

A

TRIGGER

SOURCE

switch

to

VERT

MODE.

27.

Check

that

the

B

TRIGGER

SOURCE

switch

operates

in

a

similar

manner

to

the

A

TRIGGER

SOURCE

switch

when

the

B

HORIZ

time-base

unit

is

selected

for

display.

Control

Illumination

28.

Operate

the

CONTROL

ILLUM

switch

on

the

rear

panel

to

see

that

it

controls

the

illumination

of

the

front-panel

pushbuttons.

Readout

(Deleted

by

Option

1)

The

following

three

steps

apply

only

to

instruments

equipped

with

a

Readout

System.

29.

Turn

the

READOUT

control

clockwise

until

an

alpha-numeric

display

is

visible

within

the

top

or

bottom

division

of

the

CRT

(reset

the

FOCUS

control

if

necessary

for

best

definition

of

the

readout).

Change

the

deflection

factor

of

the

vertical

unit

that

is

selected

for

display.

Notice

that the

readout

portion

of

the

display

changes

as

the

deflection

factor

is

changed.

Likewise

change

the

sweep

rate

of

the

time-base

unit

providing

the

sweep.

Notice

that

the

readout

display

for

the

time-base

unit

changes

also

as

the

sweep

rate

is

changed.

30.

Set

the

time-base

unit

for

magnified

operation.

Notice

that

the

readout

display

changes

to

indicate

the

correct

magnified

sweep

rate.

If

a

readout-coded

10X

probe

is

available

for

use

with

the

vertical

unit,

install

it

on the

input

connector

of

the

vertical

plug-in.

Notice

that

the

deflection

factor

indicated

by

the

readout

is

increased

by

10

times

when

the

probe

is

added.

Return

the

time-base

unit

to

normal

sweep

operation

and

disconnect

the

probe.

31.

Sequentially

press

all

of

the

VERTICAL

MODE

HORIZONTAL

MODE

buttons.

Notice

that

the

readout

from

a

particular

plug-in

occupies

a

specific

location

on

the

display

area.

If

either

of

the

vertical

plug-in

units

is a

®

Operating

Instructions—7704A

Operators

dual-trace

unit,

notice

that

the

readout

for

channel

2

appears

within

the

lower

division

of

the

CRT.

Beam

Finder

32.

Set

the

vertical

deflection

factor

of

the

vertical

plug-in

which

is

displayed

to

0.1

volt/division.

Notice

that

a

squarewave

display

is

not

visible

since

the

deflection

exceeds

the

scan

area

of

the

CRT.

33.

Press

the

BEAM

FINDER

button.

Notice

that

the

display

is

returned

to

the

viewing

area

in

compressed

form.

Release

the

BEAM

FINDER

switch

and

notice

that

the

display

again

disappears

from

the

viewing

area.

34.

With

the

BEAM

FINDER

button

pressed

in,

change

the

vertical

and

horizontal

deflection

factor

until

the

display

is

reduced

to

about

two

divisions

vertically

and

horizontally

(when

the

time-base

unit

is

in

the

time-base

mode,

change

only

the

deflection

factor

of

the

vertical

unit).

Adjust

the

position

controls

of

the

displayed

vertical

and

horizontal

units

to

center

the

compressed

display

on

the

graticule.

Release

the

BEAM

FINDER

switch.

Notice

that

the

display

remains

within

the

viewing

area.

Calibrator

35.

Operation

of

the

0.4V

and

4V

CALIBRATOR

outputs

has

been

verified

during

the

above

procedure.

To

check

the

40

mV

output,

connect

a

lead

between

it

and

the

left

vertical

input.

Set the

vertical

deflection

factor

to

10

mV/division

and

notice

that

a

four-division

squarewave

signal

is

displayed.

Z-Axis

Input

(Deleted

by

Option

7)

36.

Connect

a

signal

(five

volts

peak-to-peak

minimum)

to

both

the

input

connector

of

the

displayed

vertical

unit

and

the

Z-AXIS

INPUT

connector.

Set

the

sweep

rate

of

the

displayed

time

base

to

display

about

five

cycles

of

the

waveform.

Adjust

the

amplitude

of

the

signal

generator

until

intensity

modulation

is

visible

on

the

display

(change

the

vertical

deflection

factor

as

necessary

to

produce

an

on-screen

display).

The

positive

peaks

of

the

waveform

should

be

blanked

out

and

the

negative

peaks

intensified.

Notice

that

the

setting

of

the

intensity

controls

determines

the

amount

of

intensity

modulation

that

is

visible.

37.

This

completes

the

basic

operating

procedure.

Instrument

operations

not

explained

here,

or

operations

which

need

further

explanation,

are

discussed

under

“Detailed

Operating

Information”

on

pages

1-9

through

1-17.

Operating

Instructions—7704A

Operators

SIMPLIFIED

OPERATING

INSTRUCTIONS

General

The

following

information

will

aid

in

quickly

obtaining

the

correct

setting

for

the

7704A

controls

to

present

the

various

types

of

displays.

The

operator

should

be

familiar

with

the

basic

function

and

operation

of

this

instrument

before

using

this

simplified

procedure.

For

more

detailed

operating

information

on

the

plug-in

units,

see

their

individual

instruction

manuals.

For

simplicity

of

explanation,

these

directions

recommend

using

the

LEFT

VERT

and

A

HORIZ

compart-

ments

for

single-signal

and/or

single-sweep-rate

displays.

The

other

two

compartments

can

be

used

instead

if

the

procedure

is

changed

accordingly.

Single-Trace

Display

of

One

Signal

The

following

procedure

will

provide

a

display

of

a

single

signal

on

one

time-base:

1.

Connect

the

signal

to

the

input

connector

of

a

vertical

plug-in

unit

installed

in

the

LEFT

VERT

compartment;

install

a

time-base

plug-in

unit

in

the

B

HORIZ

compartment.

2.

Set the

7704A

front-panel

switches

as

follows:

VERTICAL

MODE

LEFT

HORIZONTAL

MODE

B

TRIGGER

SOURCE

VERT

MODE

or

LEFT

VERT

3.

Adjust

the

plug-in

controls

for

the

desired

display.

Dual-Sweep-Rate

Display

of

One

Signal

The

following

procedure

will

display

the

signal

from

one

vertical

plug-in

unit

on

two

separate

traces

at

two

independent

sweep

rates:

1.

Connect

the

signal

to

the

input

connector

of

a

vertical

plug-in

unit

installed

in

the

LEFT

VERT

compart-

ment

and_

install

time-base

plug-ins

in

both

HORIZ

compartments.

2.

Set the

7704A

front-panel

switches

as

follows:

VERTICAL

MODE

LEFT

A

TRIGGER

SOURCE

LEFT

VERT

HORIZONTAL

MODE

ALT

or

CHOP

B

TRIGGER

SOURCE

LEFT

VERT

138

3.

Adjust

the

plug-in

controls

as

needed

for

the

desired

display.

For

more

information

on

choice

of

dual-sweep

modes,

see

‘Dual-Sweep

Displays’

on

page

0-00.

4.

Adjust

the

VERT

TRACE

SEPARATION

(B)

control

to

position

the

B

Trace

somewhat

below

the

A

Trace

(to

avoid

confusion

when

adjusting

A

INTENSITY

and

B

INTENSITY).

Dual-Trace

Single-Sweep-Rate

Display

of

Two

Signals

The

following

procedure

will

provide

a

display

of

two

signals

on

two

separate

traces

at

a

single

sweep-rate:

1.

Connect

one

signal

to

a

vertical

plug-in

installed

in

the

LEFT

VERT

compartment,

connect

the

other

signal

to

a

vertical

plug-in

installed

in

the

RIGHT

VERT

compart-

ment,

and

install

a

time-base

plug-in

in

the

B

HORIZ

compartment.

2.

Set

the

7704A

front-panel

switches

as

follows:

VERTICAL

MODE

ALT

or

CHOP

HORIZONTAL

MODE

B

TRIGGER

SOURCE

VERT

MODE

3.

Adjust

the

plug-in

controls

as

needed

for

the

desired

display.

For

more

information

on

choice

of

dual-trace

mode,

see

‘Alternate

Mode”

and

‘‘Chopped

Mode’

on

page

0-00.

Dual-Trace

Dual-Sweep-Rate

Display

of

Two

Signals

(Independent

Pairs)

The

following

procedure

will

provide

a

display

having

the

signal

applied

to

the

LEFT

VERTICAL

unit

displayed

on

one

trace

at

the

sweep

rate

of

the

B

HORIZ

time-base

unit

and

the

signal

applied

to

the

RIGHT

VERTICAL

unit

displayed

on

another

trace

at

the

sweep

rate

of

the A

HORIZ

time-base

unit:

1.

Connect

one

signal

to

a

vertical

plug-in

installed

in

the

LEFT

VERT

compartment,

connect

the

other

signal

to

a

vertical

plug-in

installed

in

the

RIGHT

VERT

compartment,

and

install

time-base

plug-ins

in

the A

HORIZ

and

B

HORIZ

compartments.

2.

Set

the

7704A

controls

as

follows:

VERTICAL

MODE

ALT

A

TRIGGER

SOURCE

RIGHT

VERT

HORIZONTAL

MODE

ALT

or

CHOP

B

TRIGGER

SOURCE

LERT

VERT

TRACE

SEP

(B)

As

needed

3.

Adjust

the

plug-in

controls

as

needed

for

the

desired

display.

For

more

information,

see

‘Vertical

Alternate

Mode’

on

page

1-13

and

‘Horizontal

Alternate

Mode’

on

page

1-14.

Delayed-Sweep

Display

1.

Connect

the

signal

to

a

vertical

plug-in

unit

installed

in

the

LEFT

VERT

compartment,

install

a

delaying

time-base

unit

in

the

A

HORIZ

(DELAYING

TIME

BASE)

compartment

and

any

7B-series

time-base

unit

in

the

B

HORIZ

compartment.

2.

Set the

7704A

front-panel

controls

as

follows:

VERTICAL

MODE

LEFT

A

TRIGGER

SOURCE

LEFT

VERT

HORIZONTAL

MODE

A

3.

Follow

the

procedure

given

in

the

delaying

sweep

time-base

unit’s

Instruction

Manual

to

obtain

a

stable

delayed-sweep

display.

4,

Set

HORIZONTAL

MODE

to

‘A’

to

obtain

an ‘A

Intensified

by

B’

display;

set

HORIZONTAL

MODE

to

‘B’

to

obtain

a

delayed-sweep

display;

or

use

‘ALT’

or

‘CHOP’

HORIZONTAL

MODE

to

display

the

intensified

and

delayed

displays

at

the

same

time.

NOTE

When

operating

in

the

delayed-sweep

mode,

there

is

no

special

display

relationship

between

the

vertical

and

horizontal

plug-ins

(as

for

independent

pairs

operation)

regardless

of

the

vertical

mode

selected.

X-Y

Display

The

following

procedure

will

provide

an

X-Y

display

(one

signal

versus

another

rather

than

against

time).

1.

Install

7A-series

amplifier

units

in

both

the

LEFT

VERT

and

B

HORIZ

compartments.

(Note:

Time-base

units

may

be

used

in

either

or

both

compartments

if

they

provide

for

amplifier-mode

operation.)

2.

Connect

the

Y-signal

to

the

LEFT

VERT

amplifier

input

and

connect

the

X-signal

to

the

B

HORIZ

amplifier

input.

3.

Press

the

LEFT

VERT

button

of

the

VERTICAL

MODE

switch

and

the

B

button

of

the

HORIZONTAL

MODE

switch.

4.

Advance

the

B

INTENSITY

control

until

a

display

is

visible.

(If

display

is

not

visible,

press

BEAM

FINDER

switch

and

adjust

the

deflection

factors

of

both

amplifier

units

until

display

is

reduced

in

size

both

vertically

and

horizontally;

center

the

compressed

display

with

the

REV.

B,

MAY,

1977

Operating

Instructions—7704A

Operators

position

controls

and

release

the

BEAM

FINDER.)

The

amplifier

in

the

A

HORIZ

compartment

controls

the

horizontal

deflection

and

the

unit

in

the

LEFT

VERT

compartment

controls

the

vertical

deflection.

DETAILED

OPERATING

INFORMATION

Intensity

Controls

The

7704A

has

four

separate

intensity

controls.

The

A

INTEN

control

determines

the

brightness

of

the

display

produced

by

the

plug-in

in

the A

HORIZ

compartment;

the

B

INTEN

control

determines

the

brightness

of

the

display

produced

by

the

plug-in

in

the

BHORIZ

compartment.

The

INTENSITY

control

on the

display

unit

affects

both

A

and

B

traces.

The

READOUT

intensity

control

affects

the

brightness

of

only

the

readout

portion

of

the

CRT

display.

NOTE

When

using

a

delaying

time-base

unit

in

the A

HORIZ

compartment

in

conjunction

with

a

delayed

time-base

unit

in

the

B

HORIZ

compartment,

the

contrast

between

the

intensified

and

non-intensified

portions

of

the

A

sweep

is

dependent

upon

the

setting

of

the

A

INTEN

control.

The

higher

(further

cw)

the

A

INTEN

setting

the

smaller

the

contrast

between

the

intensified

and

non-intensified

portions

of

the

trace.

To

protect

the

CRT

phosphor,

do

not

turn

the

intensity

controls

higher

than

necessary

to

provide

a

satisfactory

display.

(Remember

that

the

light

filter

reduces

the

apparent

light

output

from

the

CRT.

When

using

these

filters,

avoid

advancing

the

intensity

too

high.)

If

the

beam-intensity

controls

are

advanced

to

a

point

where

the

CRT

beam

current

exceeds

a_

potentially

damaging

level

for

more

than

about

ten

milliseconds,

protection

circuitry

automatically

limits

the

beam

current

to

a

safe

level.

The

current

is

limited

to

an

even

lower

level

when

operating

in

an

X-Y

mode,

or

if

either

time-base

unit

is

set

to

a

slow-sweep

rate

(even

if

the

time-base

unit

with

slow

sweep

rate

is

not

selected

for

display

by

the

HORIZONTAL

MODE

switch).

This

reduces

the

danger

of

damaging

the

CRT

phosphor

with

a

stationary

or

slowly

moving

spot.

Since

beam-current

limiting

does

not

take

effect

until

after

about

ten

milliseconds,

the

full

display

intensity

is

available

for

most

single-shot

uses.

Display

Focus

This

instrument

contains

an

automatic-focusing

circuit

which

maintains

optimum

focus

for

all

intensity

settings

after

correct

setting

of

the

FOCUS

control

is

established.

The

easiest

way

to

obtain

correct

setting

of

the

FOCUS

control

is

to

set

the

READOUT

intensity

control

so

the

readout

portion

of

the

display

is

clearly

visible.

Then

adjust

the

FOCUS

control

for

best

definition

of

the

readout

display.

If

this

instrument

does

not

contain

the

Readout

System

(Option

1),

set

the

FOCUS

control

for

best

definition

of

a

CRT

display

at

low

intensity

settings.

1-9

Operating

Instructions—7704A

Operators

Astigmatism-Focus

Adjustments

If

a

well-defined

display

cannot

be

obtained

with

the

FOCUS

control,

adjust

the

ASTIG

adjustment

as

follows:

NOTE

To

check

for

proper

setting

of

the

ASTIG

adjustment

slowly

turn

the

FOCUS

control

through

the

optimum

setting.

If

the

ASTIG

adjustment

is

correctly

set,

the

vertical

and

horizontal

portions

of

the

display

will

come

into

sharpest

focus

at

the

same

position

of

the

FOCUS

control.

This

setting

of

the

ASTIG

adjust-

ment

should

be

correct

for

any

display.

1.

Use

the

special

jumper

lead

to

connect

one

of

the

CALIBRATOR

jacks

to

the

input

of

the

vertical

unit.

Adjust

the

vertical

deflection

factor

to

produce

a

two-

or

three-division

display.

2.

Set

the

time-base

unit

for

a

sweep

rate

of

0.2

millisecond/division.

Set

the

INTENSITY

control

so

the

display

is

at

normal

intensity

(about

midrange).

3.

Turn

the

FOCUS

control

fully

counterclockwise

and

set

the

ASTIG

adjustment

to

midrange.

4.

Adjust

the

FOCUS

control

so

the

top

and

bottom

of

the

displayed

squarewave

are

as

thin

as

possible

but

not

elongated.

5.

Set the

ASTIG

adjustment

so

the

top

and

bottom

of

the

displayed

squarewave

are

as

thin

as

possible.

6.

Repeat

steps

4

and

5

for

the

best

overall

focus.

Beam

Finder

The

BEAM

FINDER

switch

helps

locate

a

display

which

overscans

the

viewing

area

vertically

or

horizontally.

When

the

BEAM

FINDER

switch

is

pressed,

the

display

is

compressed

and

defocused

within

the

graticule

area.

To

locate

and

reposition

an

overscanned

display,

use

the

following

procedure:

1.

Press

the

BEAM

FINDER

switch.

While

the

display

is

compressed,

change

the

vertical

and

horizontal

deflection

factors

until

the

vertical

deflection

is

about

two

divisions

high

and

the

horizontal

deflection

is

about

four

divisions

wide

(the

horizontal

deflection

needs

to

be

reduced

only

when

in

the

X-Y

mode

of

operation).

2.

Adjust

the

vertical

and

horizontal

position

controls

to

center

the

display

on

the

graticule.

3.

Release

the

BEAM

FINDER

switch;

the

display

should

remain

within

the

graticule.

1-10

Control

Illumination

Switch

The

CONTROL

ILLUM

switch

on

the

rear

panel

determines

whether

or

not

the

pushbutton

switches

on the

7704A

and

the

associated

plug-in

units

are

illuminated.

Trace

Alignment

Adjustment

If

a

free-running

trace

is

not

parallel

with

the

horizontal

graticule

lines,

set

the

TRACE

ROTATION

adjustment

as

follows:

Position

the

trace

to

the

center

horizontal

line

and

adjust

the

TRACE

ROTATION

adjustment

so

the

trace

is

parallel

with

the

horizontal

graticule

lines.

Graticule

The

CRT

graticule

is

internally

marked

on

the

CRT

faceplate

to

provide

accurate,

no-parallax

measurements.

The

graticule

is

divided

into

eight

vertical

and

ten

hori-

zontal

divisions.

Each

division

is

one

centimeter

square

(except

for

Option

4,

which

uses

a

0.5

centimeter

division).

In

addition,

each

major

division

is

divided

into

five

minor

divisions

at

the

center

vertical

and

horizontal

lines.

The

vertical

gain

and

horizontal

timing

of

the

plug-ins

are

calibrated

to

the

graticule

so

accurate

measurements

can

be

made

from

the

CRT.

The

illumination

of

the

graticule

lines

can

be

varied

with

the

GRAT

ILLUM

control.

NOTE

Two

types

of

crt

graticules

have

been

used

in

some

Tektronix

oscilloscopes.

One

graticule

has

0%

and

100%

risetime

reference

points

that

are

separated

by

6

vertical

graticule

divisions.

The

other

graticule

has

the

0%

and

100%

risetime

reference

points

separated

by

5

vertical

divisions.

In

your

manual,

illustrations

of

the

crt

face

or

risetime

measurement

instructions

may

not

correspond

with

the

graticule

markings

on

your

oscilloscope.

Fig.

1-3

shows

the

graticule

and

defines

the

various

measurement

lines.

The

terminology

defined

here

will

be

used

in

all

discussions

involving

graticule

measurements.

Light

Filters

The

tinted

filter

provided

with

the

standard

instrument

minimizes

light

reflections

from

the

face

of

the

CRT

to

improve

contrast

when

viewing

the

display

under

high

ambient

light

conditions.

This

filter

should

be

removed

for

waveform

photographs

or

when

viewing

high

writing

rate

displays.

To

remove

the

filter,

pull

outward

on

the

bottom

of

the

plastic

CRT

mask

and

remove

it

from

the

CRT.

Remove

the

tinted

filter

(leave

the

metal

light

shield

in

place)

and

snap

the

plastic

CRT

mask

back

into

place.

A

clear

plastic

faceplate

protector

is

mounted

between

the

CRT

faceplate

and

the

bezel.

This

faceplate

protector

should

be

left

in

place

at

all

times

to

protect

the

CRT

faceplate

from

scratches.

REV.

B,

NOV.

1975

1div

5-div 9-div

line line line

Center

Horizontal

line

Fig.

1-3.

Graticule

measurement

lines.

An

optional

mesh

filter

is

available

at

extra

cost

(included

with

Option

3).

This

filter

provides

shielding

against

radiated

EMI

(electro-magnetic

interference)

from

the

face

of

the

CRT.

It

also

serves

as

a

light

filter

to

make

the

trace

more

visible

under

high

ambient

light

conditions.

The

mesh

filter

fits

in

place

of

the

plastic

CRT

mask

and

the

tinted

filter.

The

filter

can

be

ordered

by

TEKTRONIX

Part

No.

378-0603-00.

Readout

NOTE

If

the

Readout

System

is

not

installed

in

this

instrument

(Option

1),

disregard

the

following

information.

The

Readout

System

provides

an

alphanumeric

display

of

information

on

the

CRT

along

with

the

analog

waveform

displays.

The

information

displayed

by

the

Readout

System

is

obtained

from

the

plug-in

units

installed

in

the

plug-in

compartments.

The

characters

of

the

readout

display

are

written

by

the

CRT

beam

on

a

time-shared

basis

with

the

signal

waveforms.

The

Readout

Mode

switch

(located

behind

the

right

side

panel

of

the

Acquisition

Unit,

see

Fig.

1-4)

determines

the

operating

mode

of

the

Readout

System.

When

this

switch

is

in

the

“FR”

(Free

Run)

position,

the

Readout

System

operates

in

a

free-running

mode

to

randomly

interrupt

the

waveform

display

to

display

characters.

The

waveform

display

is

interrupted

for

only

about

20

microseconds

for

each

character

that

is

displayed.

REV.

B,

MAR.

1975

Operating

Instructions—7704A

Operators

Fig. 1-4.

Location

of

Readout

Mode

switch

(behind

right

side

panel).

In

the

“Gated”

position,

the

Readout

System

is

locked

out

so

no

characters

are

displayed

during

the

sweep.

At

the

end

of

the

sweep,

the

Readout

System

is

triggered

and

a

complete

frame

of

all

applicable

readout

words

is

displayed.

The

trigger

for

the

Readout

System

in

the

Gate

Trig’d

position

is

produced

from

the

sweep

gate

selected

by

the

Gate

switch

(located

on

same

board

as

Readout

Mode

switch)

and

is

the

same

as

the

gate

signal

connected

to

the

rear

panel

+

GATE

connector.

A

time-base

unit

must

be

installed

in

the

selected

horizontal

compartment.

The readout

information

from

each

plug-in

is

called

a

word. Up

to

eight

words

of

readout

information

can

be

displayed

on

the

CRT

(two

channels

from

each

of

the

four

plug-in

compartments).

The

location

at

which

each

readout

word

is

presented

is

fixed

and

is

directly

the

plug-in

unit

and

channel

from

which

it

originated.

Fig.

1-5

shows

the

area

of

the

graticule

where

the

readout

from

each

plug-in

unit

and/or

channel

is

displayed.

Notice

that

the

readout

from

channel

1

of

each

plug-in

unit

is

displayed

in

the

top

division

of

the

graticule

and

the

readout

from

channel

2

is

displayed

directly

below

in

the

bottom

division

of

the

graticule.

Only

the

readout

from

plug-ins

and/or

1-11

Operating

Instructions—7704A

Operators

T

I I

ais

T

i

“i

Left

Vertical

Right

Vertical

+

A

Horizontal

B

Horizontal

Channel

1

Channel

1

nis

Channel

1

Channel

7

+

>

ate

+

ae

HH

a

ae

|

T

a

|

=

|

t

|

4

senee

4

+

|

Left

Vertical

Right

Vertical

+

A

Horizontal

B

Horizontal

|

Channel

2

Channel

2 Tr

Channel

2

Channel

2

Lot

|

_

|

Fig.

1-5.

Location

of

readout

on

the

CRT

identifying

the

Originating

plug-in

and

channel.

channels

which

are

selected

for

display

by

the

MODE

switches,

appear

in

the

readout

display.

(Some

special

purpose

plug-in

units

may

over-ride

the

mode

switches

to

display

readout

even

though

the

compartment

is

not

selected

for

waveform

display.)

An

“identify’’

feature

is

provided

by

the

Readout

System

to

link

the

readout

word

with

the

originating

plug-in

unit

and

channel

(amplifier

units

only).

When

the

“Identify”

button

of

an

amplifier

unit

is

pressed,

the

word

IDENTIFY

appears

in

the

readout

location

allocated

to

that

plug-in

and

channel.

Other

readout

words

in

the

display

remain

unchanged.

When

the

“‘Identify”

button

is

released,

the

readout

display

from

this

plug-in

channel

is

again

displayed.

Circuitry

may

also

be

provided

in

the

amplifier

unit

which

produces

a

noticeable

change

in

the

analog

waveform

display

to

identify

the

associated

trace

when

the

“‘Identify’’

button

is

pressed

(see

the

plug-in

instruction

manuals

for

details).

The

READOUT

control

determines

the

intensity

of

only

the

readout

portion

of

the

display,

independent

of

the

other

traces.

The

Readout

System

is

inoperative

in

the

fully

counterclockwise

OFF

position. This

may

be

desirable

when

the

top

and

bottom

divisions

of

the

graticule

are

to

be

used

for

waveform

display,

or

when

the

trace

interrup-

tions

necessary

to

display

characters

interfer

with

the

waveform

display.

NOTE

If

the

instrument

is

to

be

operated

with

the

Readout

System

board

removed,

the

center

conductor

of

1-12

J2004

(on

Main

Interface

Board)

must

be

grounded.

Failure

to

make

this

wiring

change

will

result

in

timing

error,

particularly

at

fast

sweep

rates.

Vertical

and

Horizontal

Mode

Switch

Logic

There

are

20

possible

combinations

of

VERTICAL

MODE

and

HORIZONTAL

MODE

switch

settings.

The

total

possible

number

of

display

combinations

is

further

multiplied

by

the

variety

of

plug-in

units

available

for

use

with

this

instrument,

the

interchangeability

of

plug-ins

(i.e.,

an

amplifier

or

time-base

unit

can

be

installed

in

either

of

the

vertical

or

horizontal

compartments),

and

by

the

capabilities

of

the

plug-in

units

which

are

used

in

the

instrument

(e.g.,

a

dual-trace

vertical

unit

can

be

used

in

either

of

the

two

single-channel

modes,

in

either

dual-trace

mode

or

added

algebraically;

a

delaying

time

base

may

be

used

either

for

a

normal

sweep

or

for

delayed

sweep).

Therefore,

it

is

difficult

to

list

all

of

the

display

combinations

which

can

occur

using

the

7704A

and

its

plug-in

units.

Table

1-1

lists

the

combination

of

VERTICAL

MODE

and

HORIZONTAL

MODE

switch

positions

available

and

the

type

of

display

provided

with

each

combination.

For

further

information

on

operation

in

each

position

of

the

VERTICAL

MODE

=

and

HORIZONTAL

MODE

switch

positions,

see

the

following

sections

on

Vertical

Mode

and

Horizontal

Mode.

TABLE

1-1

Display

Combinations!

VERTICAL

|

HORIZONTAL

MODE MODE

Comments

LEFT

A

One

trace.

Vertical

deflec-

tion

from

single

units;

hori-

B

zontal

deflection

from

single

unit,

ALT

Two

traces.

Vertical

deflec-

tion

from

single

unit;

hori-

CHOP

zontal

deflection

from

both

units.

ALT

A

Two

traces.

Vertical

deflec-

tion

from

both

units;

hori-

B

zontal

deflection

from

single

unit.

ALT

Two

traces.

Vertical

deflec-

tion

from

both

units;

hori-

CHOP

zontal

deflection

from

both

units.

Provides

independent-

pairs

operation

between

the

LEFT

VERT

and

B

HORIZ

plug-ins

and

the

RIGHT

VERT

and

A

HORIZ

plug-

ins.

Combinations

given

for

single-channel

vertical

and

horizontal

units

only.

TABLE

1-1

(cont)

VERTICAL

|

HORIZONTAL

MODE

Comments

ADD

A

One

trace.

Vertical

deflec-

tion

is

algebraic

summation

B

of

both

units;

horizontal

de-

flection

from

single

unit.

ALT

‘Two

traces.

Vertical

deflec-

tion

is

algebraic

summation

CHOP

of

both

units;

horizontal

de-

flection

from both

units.

CHOP

A

Two

traces.

Vertical

deflec-

tion

from

both

units;

hori-

B

zontal

deflection

from

single

unit.

ALT

Four

traces.

Vertical

deflec-

tion

from

both

units;

hori-

CHOP

zontal

deflection

from

both

units.

RIGHT

A

One

trace.

Vertical

deflec-

tion

from

single

unit;

hori-

B

zontal

deflection

from

single

unit.

ALT

Two

traces.

Vertical

deflec-

tion

from

single

unit;

hori-

CHOP

zontal

deflection

from

both

units.

Vertical

Modes

Left

or

Right

Modes.

When

the

LEFT

or

RIGHT

button

of

the

VERTICAL

MODE

switch

is

pressed,

only

the

signal

from

the

plug-in

unit

in

the

selected

compartment

is

displayed.

Alternate

Mode.

The

ALT

position

of

the

VERTICAL

MODE

switch

produces

a

display

which

alternates

between

the

LEFT

VERT

and

RIGHT

VERT

compartments

with

each

sweep

of

the

CRT.

Although

the

ALT

mode

can

be

used

at

all

sweep

rates,

the

CHOP

mode

provides

a

more

satisfactory

display

at

sweep

rates

below

about

20

milliseconds/division.

At

these

slower

sweep

rates,

alternate-mode

switching

becomes

perceptible.

Alternate

Mode

displays

have

three

types

of

triggering

available.

When

the

A

and

B

TRIGGER

SOURCE

switches

are

set

to

the

VERT

MODE

positions,

each

sweep

is

triggered

by

the

signal

being

displayed

on

the

CRT.

This

provides

a

stable

display

of

two

unrelated

signals,

but

does

not

indicate

the

time

relationship

between

the

signals.

In

either

the

LEFT

VERT

or

the

RIGHT

VERT

positions

of

the

TRIGGER

SOURCE

switches,

the

two

signals

are

®

Operating

Instructions—7704A

Operators

displayed

showing

true

time

relationship.

However,

if

the

signals

are

not

time

related,

the

display

from

the

plug-in

which

is

not

providing

a

trigger

signal

will

be

unstable

on

the

CRT.

When

the

ALT

vertical

mode

is

selected

and

either

the

ALT

or

CHOP

buttons

of

the

HORIZONTAL

MODE

switch

are

pressed,

the

instrument

operates

in

the

independent-pairs

mode.

Under

this

condition,

the

LEFT

VERT

unit

is

always

displayed

at

the

sweep

rate

of

the

B

HORIZ

time-base

unit,

and

the

RIGHT

VERT

unit

is

displayed

at

the

sweep

rate

of

the

A

HORIZ

time-base

unit

(non-delayed

sweep

only).

This

results

in

two

displays

that

have

completely

independent

vertical

deflection

and

sweep

rate.

This

display

is

equivalent

to

the

display

obtainable

with

a

dual-beam

oscilloscope

for

most

repetitive

display

combinations.

If

delayed-sweep

operation

is

used

with

this

Mode,

a

different

sequence

is

displayed.

First,

the

LEFT

VERT

unit

is

displayed

at

the

sweep

rate

of

the

A

HORIZ

time-base

unit

(delaying

sweep)

and

then

at

the

sweep

rate

of

the

B

HORIZ

time-base

unit

(delayed

sweep).

The

vertical

display

then

shifts

to

the

RIGHT

VERT

unit

and

its

signal

is

displayed

consecutively

at

the

delaying

and

delayed

sweep

rate.

Chopped

Mode

(Vertical).

The

CHOP

position

of

the

VERTICAL

MODE

switch

produces

a

display

which

is

electronically

switched

between

channels

at

a

_

one-

megahertz

rate.

In

general,

the

CHOP

mode

provides

the

best

display

at

sweep

rates

slower

than

about

20

milliseconds/division

or

whenever

dual-trace,

single-shot

phenomena

are

to

be

displayed.

At

faster

sweep

rates

the

chopped

switching

becomes

apparent

and

may

interfer

with

the

display.

NOTE

An

internal

Chop.

Freq.

switch

(mounted

on

the

lower-left

corner

of

the

Main

Interface

board)

can

be

set

to

provide

a

vertical

chop

rate

of

either

100

kHz

or

1

MHz.

The

100

kHz

rate

is

provided

for

other

systems

using

the

A7704

Acquisition

Unit

(the

bottom

half

of

the

7704A).

For

normal

operation

of

the

7704A,

this

switch

should

be

left

in

the

‘2

MHz’

position.

When

the

A

or

B

TRIGGER

SOURCE

switches

are

set

to

VERT

MODE,

internal

trigger

signals

from

the

vertical

plug-ins

are

algebraically

added

and

the

time-base

units

are

triggered

from

the

resultant

signal.

The

LEFT

VERT

or

RIGHT

VERT

trigger

source

positions

trigger

the

time-base

units on

the

internal

trigger

signal

from

the

selected

vertical

unit

only.

This

allows

two

time-related

signals

to

be

displayed

showing

true

time

relationship.

(If

the

signals

are

not

time-related,

the

display

from

the

channel

which

is

not

providing

the

trigger

signal

will

appear

unstable.)

1-13

Operating

Instructions—7704A

Operators

The

CHOP

mode

can

be

used

to

compare

two

single-

shot,

transient,

or

random

signals

which

occur

within

the

time

interval

determined

by

the

time-base

unit

(ten

times

selected

sweep

rate).

To

provide

correct

triggering,

the

display

which

provides

the

trigger

signal

must

precede

the

second

display

in

time.

Since

the

signals

show

true

time

relationship,

time-difference

measurements

can

be

made

from

the

display.

Algebraic

Addition.

The

ADD

position

of

the

VERTI-

CAL

MODE

switch

can

be

used

(1)

to

display

the

sum

or

difference

of

two

signals,

(2)

for

common-mode

rejection

to

remove

an

undesired

signal,

or

(3)

for

DC

offset

(applying

a

DC

voltage

to

one

channel

to

offset

the

DC

component

of

a

signal

on

the

other

channel).

The

common-

mode

rejection

ratio

between

the

vertical

plug-in

compart-

ments

is

at

least

10:1

at

150

megahertz.

The

rejection

ratio

increases

to

100:1

at

20

megahertz.

The

overall

deflection

on

the

CRT

in

the

ADD

mode

is

the

resultant

of

the

algebraic

addition

of

the

signals

from

the

two

vertical

plug-in

units.

It

is

difficult

to

determine

the

voltage

amplitude

of

the

resultant

display

unless

the

amplitude

of

the

signal

applied

to

one

of

the

plug-ins

is

known.

This

is

particularly

true

when

the

vertical

units

are

set

to

different

deflection

factors,

since

it

is

not

obvious

which

portion

of

the

display

is

a

result

of

the

signal

applied

to

either

plug-in

unit.

The

polarity

and

repetition

rate

of

the

applied

signals

also

affect

the

ADD

display.

The

following

precautions

should

be

observed

when

using

the

ADD

mode:

1.

Do

not

exceed

the

input

voltage

rating

of

the

plug-in

units.

2.

Do

not

apply

large

signals

to

the

plug-in

inputs.

A

good

rule

to

follow

is

not

to

apply

a

signal

more

than

about

eight

times

the

vertical

deflection

factor.

For

example,

with

a

vertical

deflection

factor

of

0.5

volt/division,

the

voltage

applied

to

that

plug-in

should

not

exceed

four

volts.

Larger

voltages

may

result

in

a

distorted

display.

3.

To

ensure

the

greatest

dynamic

range

in

the

ADD

mode,

set

the

position

controls

of

the

plug-in

units

to

a

setting

which

would

result

in

a

mid-screen

display

if

viewed

in

the

LEFT

or

RIGHT

positions

of

the

VERTICAL

MODE

switch.

4.

For

similar

response

from

each

channel,

use

identical

plug-ins

and

set

the

plug-in

units

for

the

same

input

coupling.

1-14

Horizontal

Modes

A

and

B.

When

either

the

A

or

B

button

of

the

HORIZONTAL

MODE

switch

is

pressed,

the

signal

is

displayed

at

the

sweep

rate

of

the

selected

time-base

unit.

Set

the

applicable

intensity

control

and

trigger

source

switch

for

the

desired

display.

Alternate

Mode.

The

ALT

position

of

the

HORI-

ZONTAL

MODE

switch

produces

a

display

which

alter-

nates

between

time-base

units

after

each

sweep

on

the

CRT.

Although

the

ALT

horizontal

mode

can

be

used

at

all

sweep

rates,

the

CHOP

horizontal

mode

provides

a

more

satisfactory

display

at

sweep

rates

below

about

20

milliseconds/division.

At

slower

sweep

rates,

the

switching

between

the

alternate-mode

traces

becomes

apparent

and

may

interfere

with

correct

analysis

of

the

display.

NOTE

This

instrument

will

not

operate

in

the

ALT

position

of

the

HORIZONTAL

MODE

switch

if

either

hori-

zontal

plug-in

compartment

is

left

vacant.

The

A

and

B

INTENSITY

controls

allow

individual

adjustment

of

the

traces

produced

by

the

time-base

units

in

the

A

HORIZ

and

B

HORIZ

compartments.

Correct

triggering

of

both

time-base

units

is

essential

to

obtaining

the

correct

display

in

the

ALT

horizontal

mode.

If

either

of

the

time-base

units

does

not

receive

a

correct

trigger,

and

therefore,

does

not

produce

a

sweep,

the

other

unit

cannot

produce

a

sweep

either.

This

means

that

one

time-base

unit

cannot

begin

its

sweep

until

the

has

com-

pleted

its

entire

display.

This

can

be

avoided

if

the

time-base

units

are

set

for

auto-mode

triggering

(sweep

free

runs

if

not

correctly

triggered).

See

‘Trigger

Source’

for

operation

of

the

A

and

B

TRIGGER

SOURCE

switches.

Also,

see

‘Vertical

Trace

Separation’

for

information

on

positioning

the

B

HORIZ

display

when

in

the

ALT

dual-sweep

mode.

Chopped

Mode

(Horizontal).

When

the

CHOP

button

of

the

HORIZONTAL

MODE

switch

is

pressed,

the

display

is

electronically

switched

between

the

two

time-base

units

at

a

2

megahertz

rate.

In

general,

the

CHOP

horizontal

mode

provides

the

best

display

when

either

of

the

time-base

units

is

set

to

a

sweep

rate

slower

than

about

20

milliseconds/

division.

It

also

provides

the

best

display

when

the

two

time-base

units

are

set to

widely

varying

sweep

rates.

In

the

CHOP

horizontal

mode,

equal

time

segments

are

displayed

from

each

of

the

time-base

units.

This

provides

a

display

which

does

not

change

greatly

in

intensity

as

the

sweep

rate

of

one

of

the

time-base

units

is

reduced

(in

contrast

to

ALT

horizontal

mode

operation

where

the

slowest

trace

tends

to

be

the

brightest).

Tektronix 7704A User manual

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