Tektronix 7A22 Instruction Manual



COMMITTED

TO

EXCELLENCE

Tektronix,
P

.O.Box

Beaverton,

Inc

500

Oregon

CHECK

REAR

.

97077

O

FOR

THIS

Serial

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MANUAL

N

Number

INFORMATION

.

MANUAL

070-0931-00
Product

Group

42

First

Printing

Revised

SEP

JUL

1986

1969













1969

Copyright
Contentsofthis
form

without

C

the

Tektronix,

publication

written

permission

Inc.All

notbereproducedinany

may

rights

'Tektronix,

of

reserved
Inc

.

.

ProductsofTektronix,

and

by U.S.
TEKTRONIX,

registered

registered

is

a

PrintedinU
are

reserved

Each
or

stamped
designates
of

the

unique

United

manufactureisidentifiedasfollows

foreign

TEK,

trademarksofTektronix,

trademarkofTektronixU.K.Limited

.S .A

.

INSTRUMENT

instrument

on

the

countryofmanufacture

serial

number

to

each

States

Inc.and

patents

SCOPE-MOBILE,

Specification

.

has a

the

instrument.Those

have

and/or

SERIAL

serial

number

chassis.The

are

assigned

six

unique

its

and

subsidiaries

pending

and

Inc.TELEQUIPMENT

price

NUMBERS

on a

first

.

sequentially

manufactured

digits.The

:

patents

change

panel

number

The

are

last

country

covered

.

T

4

are

.

privileges

insert,

tag,

or

letter

five

digits

and

are

in

the

of

B000000
100000
200000
300000
700000

Tektronix,
Tektronix
Tektronix

Sony/Tektronix,
Tektronix

The

Inc.,Beaverton,

Guernsey,

United

Holland,

Netherlands

Ltd.,Channel

Kingdom,

Japan

NV,

Oregon,

Ltd.,London

Heerenveen,

USA

Islands





7A22

Section

Section

1

SPECIFICATION
Introduction
Electrical

Deflection
Gain.. .
Differential
DC
Frequency
Bandwidth
Recovery
Common-Mode
Common-Mode
Maximum

Input
Maximum

Variable
Step

Displayed Noise
Measured)

DC
Isolation

Inputs

Environmental

Altitude

Transportation

Physical

Finish
Dimensions

Weight

2

OPERATING

Introduction
Front

Operating

First

General

Trace

Input

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

Characteristics

. . . .

Factor.. . . . . . ... . . . . . .

. . . . . .

. .

. . . . . .

Offset

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

Dynamic

Response

Range.. . . . . .

. . .

Limit.. . . . . . .

Time..

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

Signal
Rejection Ratio

Input

Voltage.... . . . . ..1-3

R

andC. . . . . . . . . . . . . . ...

Input

Gate

Current

Balance..

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

AttenuatorDCBalance

(Tangentially

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

Drift

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

Between+and

. . . . .

. .

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

Characteristics

. . . .

. .

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

. . . . . .

. .

Characteristics

. . . . .

. .
. .

. . . .

. .

. ... . . . . .

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

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

. . . . . .

. .

INSTRUCTIONS

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

.

Panel

Instructions

Time

Operating

Drift

Gate

Current

Controls

Operation

and

Connectors

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

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

Information

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

. .

.

. .

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

. .

. . . . . .

. .

. . . . . . .

. .

. . . . . . .

. .

. . . . . . .

. .

. . . . . . .

Range

. . . ..1-1

. . ...

. . ... .

---

. . . .

. . . . . .

. . . . . . ... .

. . . . . ... .

. ... . . .

Page

1-1
1-1

1-1
1-1
1-1
1-1
1-1
1-1
1-1

. . ..1-1

1-3

.

1-3

.
.

1-3
1-3

. ..1-3

1-3

. . ..1-3

. .

. .

1-3

. .

. .

1-3

. .

. .

1-3

. .

. .

1-3

. .

. .

1-3

. .

. .

1-3
1-3

2-1

.

2-1
2-2

2-2
2-4
2-4
2-4

Section

2OPERATING

(cont)
Voltage

Signal
High
Display
Deflection
Bandwidth
Voltage
Differential

DC
Input
Readout

The

remaining

servicing

portion

instructions
usebyqualified
do

notperform

operating

Section 3

any

instructions

CIRCUIT
Introduction
Block

General

Detailed

INSTRUCTIONS

Measurement

Input

Connectors

Input

Impedance.. . . . . . . . . . . . .2-5

Polarity

Factor

Selection

Comparison

Operation

Offset

Operation

Overdrive

.

. . . ... . . . . . . ... . . . . .2-5

. . . ... . . . . ... . . . . .2-5

. . . . . ... . . . . . . .2-5

Measurements

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

. . . . . .

Indicator

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

Trace

Identify

.

personnel

servicing

unless

. . . . . . . . . ... . . . . . . .2-13

of

this

servicing

These

only.To

other

qualifiedtodoso

TableofContents

avoid

than

DESCRIPTION

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

Diagram
Input
Input
Preamp

F

---3dBPoint

L
Output
HF

--3

Feedback
Differential

Input
Input

Description
Coupling
Attenuators

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

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

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

.

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

Amplifier

dB

Information

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

Point

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

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

Amplifiers

Configuration

Circuit

Description
Coupling
Attenuators

.

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

. . . . . . . . . . .

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

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

. . .2-10

. .

. . . . . .

. . ... . . . . . .

lists

instructions

electrical

that

called

outinthe

.

. . . . . ... . .

... . . . . . .

. .

. .

. . . . ... . .

. . . . . .

. .

. .

. .

. .

. .

. .

Page

2-4
2-4

2-10
.2-11
.2-12

2-12

the

for

are

shock,

3-1
3-1
3-1
3-1
3-1

3-1
3-2

3-2
3-2
3-2

3-3
3-3
3-3
3-4

REVSEP

1981

7A22

SECTION

SECTION

3

4

CIRCUIT

DESCRIPTION

Gate

Current

Input

Amplifier

X15

Preamp.. . . .

DC

Balance.. . . . . . . . . .

Floating
Common-Mode
Cross

Neutralization.. . .

Overdrive

Input

Offset

DC

Offset

Generator

Input

Overdrive

LF--3dBPoint

Output

Gain

Amplifier

Switching

Variable

Signal

Output

Trigger

Indicator

Probe
Trace

Oscilloscope
Sensing

Identify

MAINTENANCE

Introduction
Preventive

General
Cleaning

Cleaning
Visual

Maintenance

. . . . . . . .

Front
Interior

Inspection

Transistor
Calibration

Corrective

Maintenance

General.. . . ...

Obtaining

(cont)

Compensation

. .

. . . . . . .

. .

. .

. . . .

Power

Supply

. . .

Rejection

Protection

. . . . . . . . .

. . .

. . . . . . .

Indicator

Selector

. . . . . . . . .

Amplifier

Output

Output

stage.. . .

Amplifier

Amplifier

. .
. .

Readout

. . . . . . . .

. . . . . . . . .

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

. . . . . .

. . . . . . . .

Panel

. . . . . .

. . . . . . . . .

... . . . . . .

Checks

. . . . ... .

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

. . . . . .

. . . . . . . .

.

Replacement

Parts

Page

.

3-4

SECTION

4

MAINTENANCE

Special
3-4 Soldering
3-4

Component
Information

3-4

Troubleshooting

3-5
3-5

.

Introduction
Indicator

.

3-6

Operating

3-7

3-7
3-7

3-8

.
.

3-9
3-9

.

3-9
3-11
3-11
3-11

Control
Trouble

Visual

Calibration

Detailed

Test
DC

TroubleshootingbyDirect
Replacement

Components

3-11

.

3-11
3-11

Repackaging

4-1
4-1
4-1

4-1
4-1

4-1
4-1

4-1
4-1
4-1
4-2

SECTION

5

PERFORMANCE
CALIBRATION

Introduction
Test

Short
Performance

Procedure

General

General

Preliminary

(cont)

. . . . . . .

Parts

Techniques

Replacement

. . . . . . . . .

. . . . . . . . . . .

.

. . . . . . . . . .

. . .

Oscilloscope

Procedure

Settings

. .

Symptoms

Inspection

Check

Troubleshooting..

Equipment

Balance

Recommended

Check

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

Checks

Transistors

. . . . . . . . . . .

Diodes.. . . .

Resistors
Capacitors

. .

. . ... . .

. . . .

for

Shipment.. . .

CHECK/

PROCEDURE

. . . . . .

Equipment

Required..

. . . . . . . .

Form

Procedure

Check/Calibration

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

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

Procedure

. . . ..4-2

. . . . . .

. . . .

. . . . .

and

.

. . . . . .

.

. . . .

. . .

.

. . . . . . . . .

. . . . . . .

. .

. . . . . . . .

. . . . . .

. . . . . . . . .

. . . .

. . . . .

..4-9

.

. . . . . . . . .

. . .

. . . . . . . .

. . . . . . .

. . .

. . . . .

Page

4-2

4-3
4-5
4-5
4-5

4-5
4-5

4-5

.

4-5

.

4-5
4-6
4-6

4-6

4-6
4-6
4-8
4-8

4-9

5-1
5-1

5-1
5-2

5-3
5-3

5-3

REVC,MAR

197

9





7A22

SECTION

5

PERFORMANCE
CALIBRATION
(cont)

or

Step Atten

AC
Variable

Coarse
+

Gate

----

Gate

GAIN

Adjust

Balance

DC
Current
Current

. .

Check

VARIABLE
VOLTS/DIV

Isolation
Inputs

.
TotalDCOffset
C241

+Cross

C141

--Cross Neutralization

C115

X1

Constant
C215

X1

Constant.. . . . . . . .

Input

Atten

Input

Atten

Balance

--l-Input

Atteh

Conpensation

-Input

---Input

Atten
Atten

Compensation

HF-3dB

CHECK/

PROCEDURE

Page

--

. .

5-4
5-4

.

5-4
5-4

5-5

5-5
5-5

5-5
5-5

. . . . . . . . . .

Balance..

. . . . . . .

Balance

Zero
Zero

. . . . .

. . . . .

. . . . .

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

Control Ratio

Gain

Switching

4-

between

and

. . . . . . . . . . ....5-6

Range

Neutralization

. . .

5-6

5-7
5-7

Atten

Atten

Time

Time

. . . .

. . .

5-7

5-7

.

5-8

-I-Input
.

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

-Input

Accuracy

Differential

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

.

5-8

Series

. . . .

5-9
5-9

. . .

. .

Compensation
Shunt

. . . . . . . . .

Point

. . . . . . . .

5-10
5-11

SECTION

SECTION

SECTION

SECTION

PERFORMANCE

5

CALIBRATION
(cont)

L F

CMRR
Input
Differential

Overall
(Measured

Overdrive

ELECTRICAL

6

Abbreviations

Parts

Ordering
IndexofElectrical
Electrical

DIAGRAMS

7

PARTS
Diagrams
Mechanical

MECHANICAL

8

Mechanical
Index

of

Illustrations
Mechanical
Accessories

CHECK/

PROCEDURE

---3dBPoint..

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

Overdrive

Indicator.5-12

Dynamic

Noise

Level

Tangentially)

Recovery

PARTS
and

Symbols

Information

Parts

Parts

List

AND

MECHANICAL

ILLUSTRATIONS

Parts

Illustrations

PARTS

Parts

List

Mechanical

Parts

Parts

List

. . . . . .

.

Range

. .

Time

.5-14

LIST

List

LIST

Information

Page

5-11
5-12

5-13

5-13

Abbreviations
taken

Units",
industry.Change
manual

B,

MAR

197

REV

9

directly

MIL

STD-12B

.

and

symbols

from

IEEE

information,

Standard

and

other

usedinthis

260

standards

any,islocated

if

manual

"Standard

of

atthe

are

basedonor

Symbols

the

electronics

rear of

for

this

Type

7A22

Fig.1-1.Type

7A22

Differential

Amplifier

.





Type

7A22

Introduction

The

Type

ential

amplifier

acteristics

The

display

a

large

AC
Type

quency
to
quency

by

width

provide
ducer,
factor,

The

oscilloscopes

The
valid
calibrated
and

and

DC

Offset capability

of

the

DC

component,atdeflection

coupling.The

7A22

is

--3

dBpoints

set the

restricting

bandwidth

applications

selection

measurement

and

other

low

noise

Type7A22isdesigned

.

electrical

over

the

at

after

a

5

ELECTRICAL

Change

rear

7A22

Vertical

with

excellent

high gain

very

small

vertical

from

10/W

the

the

bandwidth

and

excellent

areas
measurements

characteristics

stated

an

ambient

minute

information,ifany,
the

of

for

canbe

of

the

signal-to-noise

capabilitiesinthe

which

environmental

temperatureof+20'C

warmup

manual

Plug-inisa

common-mode

low

level

of the

low-frequency

deflection

to10V

of

for

Type

factors

.The

selectedatthe

instrument.Thus,

ratio

the

Type

drift-with-time

require

stable,

.

useinTektronix

described

range

unless

otherwise

CHARACTERISTICS

.

DC

coupled

rejection

applications

7A22

signals

not

possible

factor

range

high

and

front
for

canbeimproved

7A22.The

characteristics

biomedical,

low

7000

in this

section

for

noted

affecting

differ-

char-

.

allows

the

containing

with

of

the

low

fre

panel,

low

fre-

band-

trans-

deflection

Series

are

instruments

to

+30°C

.

this

section

DC

OFFSET

COARSE
Electrical

10

[tV/Div

10

mV/Div

20

mV

V/Div

2Vto 10

Frequency

div

Reference)

Overall

Response

Coupled
AC

(Capacitive)

pled

Input

Bandwidth

Bandwidth
Accuracy

HF

---3dBPOINT

100Hzto1MHz
Accuracy

LF

-3

0.1Hzto10

Range

Zero

to0.1

Response

Frequency

DC

Input

Frequency

Limit

dB

POINT

will

from

to

V/Div

(Direct)

Lower

kHz

(8

Cou-

be

found

At
Atleast

Within
6

at the

least

+100V

+1000Vto--1000

------

- --- --

-----------

10%

of

stepsina 1-10

to

-100V

selected

sequence

-

------

frequency

V

Characteristic

Deflection

(VOLTS/DIV)

Gain

Ratio

VAR

(CAL

Differential
(DC

OFFSET'

10 ~tV/Div

10

mV/Div

20

mV/Div

0.1V/Div

0.2V/Div
1

V/Div

2

V/Div

10

V/Div

Factor

Accuracy

IN)

Signal

not

to

to

to

to

Range

Range

used)

Performance

Within

1

mV/div

Continuously

flection
Permits

factorat1
frames

^

At

least

At

least

At

least

At

least

Requirements

2%

with

GAIN

variable;extends de-

factortoat

adjustment

mV/DIV

_F_-1

V

J-10

V

--1-100V

4-1000V

adjusted

least25V/div

of

deflection

for

all

main-

10

/usorlesstorecovertowithin

0

.5%

of

zero

level

after

the

re-

at

20

mV/Div

0.1V/Div

0

.2

V/Div

10

Common-Mode
Rejection

DC

AC

Coupled

to

to

V/Div

Ratio

(Direct)

(Capacitive)

Coupled

movalofa+or
plied

for1s.Test

ceed

Differential
Specified
on

At

At

At

test

least

least

least

aberration

signal

+10V

+100V

+500V

---

test

signal

Signal

(0

amplitude

and

and

and

input

nottoex-

.5%)

-10V

-100V

----500V

Range

based

ap-

.

m

Q

O

3

a

N

N

MHz
1

kHz 100 kHz
10

Points

Verification

kHz
1

Hz
100

Hz

3
10

10

T

N

n

3









CMRR

0

'o

xmm

a

n03

3030a

Specification-Type

7A22

ELECTRICAL

Characteristic v

Maximum
(each

DC
DC
Component1MHz
less

AC
Coupled

Input

AC
Coupled

Input

InputRandRC

Resistance
Capacitance
R

Maximum

Current

10 [,V/Div
Div

20

Div

Display

/Div

Variable

Displayed-Noise

getially

Input

input)

(Direct)

-f-

Peak

10 ttV/Divto10

mV/Div

20

mV/Divto0

V/Div
.2

V/Divto10V/

Div

(Capacitive)

DC

Voltage

(Capacitive)

DC

Rejection

__

Product

& C

Input

to10

mV/Div

Shiftat10

Coupled)

(AC

Balance

Measured)

to

CHARACTERISTICS

Voltage

Coupled,

AC,

AC

or

.1

Gate

mV/

10V

ttV

(Tan-

(cont)

Performance_Requirements'N`-

_

-j-_15V

-1-200

V

-A-500

V

-+500V,

At

1

MQ
Approximately47.0
Within

flection

_

x-25°C____

-f-20

-+-40

-+-_10pA-t:-20

.±-4

0.2T
control

fully

16,utV or0.1

greater),1MHz
source

each

input

least4X105 :1

1

ZL

.

between

factors

pA

-t=100

pA

pA

-±-=200pADifferentially
pA

div

:+-20

div

div^or

less

shift

turned

ccw

resistance

from

position

Div (whichever

HF

250

pF

all

+50C

each

with

VARIABLE

fully

----3dBPOINT,
or

less

__-

input

cw

de-

.--

DC

Drift

Drift

with

Time

(Ambi-

ent

Temperature

Line

Voltage

Short

Long

Drift

Temperature

Voltage

Isolation

--

Inputs

an

Open

INPUT
INPUT)

Term

Term

with

between

(+

-

to

an

Constant)

Constant)

Ambient
(Line

-I-

INPUT

INPUT,

Open

and

5

tkV

is

greater)inany

hour
10

~tV

is

greater)inany

hour

501AV/°Corless

and

to

--

At

least

(P-P)

or 0

.1div

(whichever

minute

after

warmup

(P-P)or0.1div (whichever

hour

after

warmup

200

:1,

1

DC

MHz

to

1

1

ENVIRONMENTAL

PLUG-INTESTED

Altitude

Non-operating

Transportation

OUTOF

INDICATOROSCILLOSCOPE

CHARACTERISTIC

To

50,000

Qualified
Transit

Category

1A,

Imo_..

. . .._.__..___ .___

feet

under

Committee

I I

___.._..__.._._. . .

and

--55°C

National

test

procedure

Safe

PHYSICAL

to

is

Finish

'

Dimensions

Weight

ITEM

____

Front

___N_~4%

_CHARACTERISTIC

panelisanodized

inch

-z25/8

Ibs

LX2%

aluminum

inch^W

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Type

7A22

The

Change

rear

Introduction

This

the

section

front-panel

opens

controls,
connectors.Following
ization
operationofthe

procedure

Type

CONTROLS

INPUT

OVERDRIVE

VOLTS/DIV

VARIABLE
(CAL

IN)

GAIN

POSITION

IDENTIFY

HIGH
FREQUENCY

----3dBPOINT

-

information,ifany,

of

the

manual

withabrief

input

the

front-panel descriptionisa

and

finallyageneral

7A22

.

AND

Input

overdrive

indicate

to
to

the

input

the

differential

input

connectorsisexceeded

Volts

per
position
brated

Two-position
VARIABLE

uncalibrated

position,

IN

operative
calibrated.When

the

knob

VARIABLE
flection

tion

provides
calibrated
brated
the

deflection

VOLTS/DIV
Screwdriver

display
VOLTS/DIV
for

proper

DIV

switch

The

control

traceordisplay
Momentary

concentric
the

trace,

Type

7A22,

when

pressed.Aidsinidentifying

Type

7A22

are displayed
Nine

position

proximate

switch

1

kHz,3kHz, 10 kHz,30kHz, 100

300

kHz,

functional

overdrive lamp,

CONNECTORS

excessive

amplifier

dynamic

displayed

switch

deflection

switch

knobtoselect

deflection

the

and

moves

control

factors.The

continuously

attenuation

deflection

.

adjust

scale

factortoagree

switch
deflection
settothe1mV

that

.

contact,

with

representing

to

trace

.

switchtoselect

high
positions

and1MHz

.

discussionofthe

indicator

differential

stage.Lights

range

division.Nineteen

used

to select

factors

activated

VARIABLE

the

outwardtoactivate

factor

POSITION.Will

move

frequency

factors.At

deflection

pressed

for

uncalibrated

uncalibrated

between

factors

to

controltoset

indication.Adjusted

with

vertically

push-button

the
a

when

multiple

are:100 Hz,

.

description

and

familiar-

lamp

turns

between

.

the

.

by

calibrated

controlisin-

factor

and

released,

variable

the

and

extends

at

least

the

with

the

VOLTS/

position

positions

switch,

cause

outputofthe

small

amount

traces

the

point

----3

dB

300

affecting

of

input

on

drive

when

cali-

the

or

the

is

the
de-

posi-

un-

cali-

25

CRT

the

.

the

the

ap-

.

Hz,

kHz,

this

section

LOW
FREQUENCY

POINT

-3

dB

INPUT

-f-

--

INPUT

INPUT

WAVEFORM

Fig.2-1.Signals
upright

display,

AC-GND-DC

J_

will

be

Eight

ingorthe

----3dBpoints.The
DC
100 Hz,1kHz,

Signal

produces

2-1)
Signal input

produces

2-1)

applied

while

signals

A

miniature
switch.The
that only
at
depressed
0

.1'cFtothe

the

nalisamplified

When
signaliscoupled
Amplifier
both

the

tons)isdepressed,
through 0
ground.The
in

this

found

position

at

the

switchtoselectDCcoupl-

approximate

switch positions are

OFFSET,

DC,.lHz,1Hz,10

and10kHz

input

connector.Positive

deflection

.

connector.Positive

deflection

downward

.

to

the

+INPUT

appliedtothe

connector

--INPUT

illuminated

one

buttons

one

time.When

button

are

may

the

the signaliscoupled

Input

Amplifier

varying

component

.

the

'DC'

buttonisdepressed

directlytothe

and

the

entire

and DC,isamplified.When

AC

'GND'

button

(or

the signaliscoupled

.1

al`

and

through1M52

Amplifier

condition

.

low

frequency

.

upward

(see

(see

produces

are

inverted

push-button

interlocked

depressed

be

'AC'

button

through

and

of

the

input

Input

input

signal,

noneofthe

Inputisgrounded

Hz,

input

Fig

input

Fig

an

type

so

only

sig-

the

but-

to

:

.

.

.

is

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Operating

---

AC-GND-DC

The
when
is

STEP
DC

BAL(DC

ONLY)

DC

OFFSET
(DC
mode

RELEASE

following

the

settoDC

ATTEN

OFFSET

only)

LATCH

Instructions----Type

LOW

or

MODE

OPERATING

First-Time

Steps1through 5inthe

to

help place

the

unit

check

remaining

functionsofthe

1.Insert

ment

.

2.Set
VOLTS/DIV

VARIABLE
POSITION

HIGH

--3dBPOINT

LOW
AC-GND-DC
AC-GND-DC
STEP

3.Turn the

clockwise
time-base
and

automatic

4.Wait

oscilloscopetowarm

Operation

the

traceonthe

for

immediate

the

GAIN

adjustment.These

are intendedtodemonstrate

Type

the

unit into

the

Type

7A22

FREQUENCY

FREQ

---3dBPOINT
(-h-

(,

ATTEN

and

and

about

DC

oscilloscope

turn

triggering

triggering

five

7A22

Each

push-button

behind

when

Same

functionasthe

switch

IMPORTANT

two

FREQUENCY

DC

Front
the
nals
the
shiftasthe
from
position

Coarse and
internal offset bias
the

range
the
andisindicated
(OFFSET
DIV

Gray
leftofthe
move

appliedtothe

but

controls

OFFSET

.

panel

amplifier

applied

controlisadjusted

VOLTS/DIV

the

10

.

differential

the

of

settingsofthe

RANGE)

switch

.

rectangular

front

Plug-In

is

the

buttonisdepressed

are operative

---3dBPOINT

control

mV

from

for

input

stage.With

to

the

positiontothe10[V

fine

controlstoprovide

while maintaining

capability

offset

bias
VOLTS/DIV

by shaded

around

knob

panel.Pull

Plug-In

INSTRUCTIONS

following

use.Steps6through8are

7A22

.

the

front-panel controlsasfollows

INPUT)
INPUT)
BAL

Intensity

the

oscilloscope

controls

.

minutes

up

.

procedure

screen

quickly

steps

oscilloscope

1

mV

(CAL)

IN

Midrange

1

MHz

DC
GND
GND
Midrange

control

Power

fora.5mssweep

for

the

Type

along

some

illuminated

-I-

AC-GND-DC

,---

DC

input

for

switchismoved

.

depends

the

near

compartment

are intended
and

of

plug-in

fully

ON.Preset the

7A22

from

INPUT

only

switch

balancing

no

connectors,

no

trace

Available

upon

switch,

gray

bands

VOLTS/

the

bottom

outtore-

prepare

used

with those

the

basic

compart-

counter-

and

.

.

sig

:

rate

the

NOTE

About
when
urements.For
the

the

6.Using

sions

ceeded,
voltages

possible.If

will
lightingofthe
input

7.Apply

a

coaxial

7A22

8.For

INPUT

.

should
bottomofthe

9.For

display
bottom

10.Set

and

to

to

its

11.Disconnect
nector.Connectadual
and

the

12.For

-INPUT
brator
mode
since

Operational

Most
be
to
warmup,
adjusted
warmup
beforeafinal

in

five

minutes

using

the

lower

deflection

hour

.

5.Adjust
trace.The

below

If

the

to10mV

--16.5volts

1/16

.

note

average

--

Calibratortothe

the

the

trace

the

POSITION

graticule

maximum

range

the inputs

of

the

A

of

current,

open.An

coupling

a 4

mV

cable

DC

coupled, single-ended

AC-GND-DC

be

square

display at

AC

coupled,

with

the

of

the

displayatthe graticule

the

-f-

that

the

level

INPUT

connectors.Connect

AC

AC-GND-DC

signalisnow

signal.A

common-mode

approximately

Type

coupled

is

Type

7A22

long-term

factors,

Intensity

should

control,

center

CAUTION

input

of

the

are

and

damage

signal

source

the input protective

open

input

INPUT

OVERDRIVE

switches

peak-to-peak

to

the

-¢-

coupling

waves4divisionsinamplitude

the

single-ended

7A22

INPUT

AC-GND-DC

display

the

straight

shifts

.

coaxial

input

dual

differential

coupling

coupledtoboth

line

is

Adjustments

NOTE

of

the

following

made

after

the

DC

drift

the

STEP

for

each

of at

BALisattempted.Insure

conjunction
brated
the

calibrated

with

(refertothe

output

checks

a 5

minute

of the

ATTEN

check

least

one

adjustment

the

oscilloscope

voltageiscorrect

sufficient

control

appear

.

voltage

VOLTS/DIV

diode-clamped

settoGND

INPUT

reference

POSITION

cable from

input

being

amplifier

hour

that

Type

time

for

short-term

DC

measurements

allow

for

near

position

ratinginthe10~tV

+

16.5volts

to

the

cansupply

fuseisindicated

indicator

calibrator

connector

operation,

switchtoDC.The

establishedinstep6.

operation,

center

coupling

downward

connector

the

connector

switch

inputs

display

should

rejected

and

adjustments

warmup;however

during

DC

BAL

or

adjustment,

should

of

the

the

oscilloscope

7A22

manual)

for

warmup

DC

meas-

using

at

least

normal

the graticule

signal

control

coaxial

operation,

STEP

is

viewing

the

trace2divi-

switchisex-

.

about2divisions

the

to

.

toAC.

.

should

correctly

fixed

to

and/or

source

more

fuse(s)

by

with

signal

on

the

set

with

reposition

to

place

line

.

switchtoAC

-¢-

INPUT

the

-¢-

cable

set the

The

as a

common-

be

observed,

subsequent

be

and a

be

allowed

ATTEN

and

.

one

center

is

than

the
the

through

Type

the

display

the

the
the

con-

INPUT

from

cali-

may

due

re-

DC
used
cali-

that

of

.

2-2

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1

.

AC

ATTEN

LOW

FREQ

---3dBPOINT
frequency
AC
to

any
DC
VOLTS/DIV
BAL, an

Fig.2-2.LocationofAC

When

to

another,itmay
adjustmentofthis
ations

An
not

control

a.With

move

Type

response

stabilization.This

position

BAL

and

except

DC

balanceisthen

internal

adjustment

transferring

control,

between

oscilloscopes

unbalance

be

reduced

.

the

Type7A22

the

left

side

7A22

controlsasfollows

VOLTS/DIV

AC-GND-DC

AC-GND-DC
LOW
HIGH

b.Using

graticule

c

.Set the

d.Adjust

the

tracetowithin1.5

(-+-INPUT)
(---INPUT)

FREQ

-3

FREQ

--3dBPOINT100

the

POSITION

center

.

VOLTS/DIV

the

AC

noteinstep1).

INTERACTION

quence,

:Ifthis

steps2and3must

BAL

(internal

switchisusedtolimit

of

the

Type

means

DC

or

OFFSET

controls

controlled

(see

ATTEN

BAL

the

Type

be

necessary

duetonormal

.

NOTE

of

up

to30I,Visnormal

by

adjusting

inserted

panel

the

of

:

dB

POINT10

control,

switchto20

ATTEN

BAL

divisionsofgraicule

adjustment

adjustment).When

7A22,

the

that

when

the switchisset

DC

OFFSET,

the

become

with

Fig.2-2)

control

7A22

.

.

from

one

to

performaminor

power

the

AC

into

the

oscilloscope,

oscilloscope

1

mV
GND
GND

Hz

Hz

position

~tV

.

control,

R505,toposition

is

made

alsobeperformed

the

unit

employs

STEP

inoperative

the

AC

oscilloscope

supply

and

can-

ATTEN

and

the

trace

center.(See

out of

.

ATTEN

ATTEN

BAL

set

the

low

re-

vari-

re-

the

to

se-

2.VAR
a

.

Set

b.Position

TION

.

c.With

VARIABLE

ment

d.Adjust

ABLE

locationofadjustment

3.STEP

the

LF
BAL

DC

vertically

its

range.The

tive

positions

a.Set

VOLTS/DIV

VARIABLE

POSITION
HIGHFREQ
LOW
AC-GND-DC
AC-GND-DC
STEP

b.Using

CRT

tracetothe

c

.

Set

d.Return

STEP

ATTEN

The
trol
of
coupled
peratures
the

frequently.It is

trol
measurement

4.GAIN
a.Perform

Procedure

b

.

Adjust

display

Accuracy
voltage

BAL

R425

the

Type7A22

the

tracetograticule

control

.

the

VAR

(CAL

control

of

trace

from stoptostop.Check

.

R425

for

controlisrotated

ATTEN

DC

---3dBPOINT
is

not properly

as

the

VOLTS/DIV

shiftismore

.

the

Type

7A22

(CAL

IN)

---3

dB POINT1

FREQ

-3

dBPOINT
(-(-INPUT)
(----INPUT)

ATTEN

the

DC

Type

BAL

centerofthe graticule

the

VOLTS/DIV

the

tracetograticule

DC

BAL

adjustment

should

the

instrument.If

be

of the

checked

orinsignificantly

in

the

STEP

ATTEN

and

readjust,ifnecessary,

is

made

steps1through8in

.

the

GAIN

.

of

this

adjustmentisdependent

accuracy

Operating

(Internal

.

Instructions-Type

adjustment)

controlsasin

center

IN)inthe

no

movement

from

out

of

stoptostop

.)

BAL.With

zero

selectoratDC,ifthe

adjusted

the

switchisrotated

noticeableatthe

front-panel

controlsasfollows

10

mV
CAL
Midrange

MHz
DC
GND

GND
Midrange

7A22POSITION

switchto10

ttV

center

control

.

NOTE

STEP

ATTEN

periodically

the

Type

7A22

varying
10
DC
good

,uV/DIV

BAL

to.1mV/DIV

should

be

practicetocheck

before

under

the

above

the

for

control

exactly4divisions

NOTE

of

the calibration

.

step

1-a

.

with the POSI-

position,

fornomove-

traceasthe

.

(See

input

voltage

STEP

CRT

trace

control,

position

.

.

by

adjusting the

DC

BAL

during

is

used

ambient

checked

this

any

conditions

First-Time

upon

source

7A22

rotate

VARI-

Fig.2-2

and

ATTEN

will

shift

throughout

most

sensi-

:

con-

the

use

DC

tem-

ranges,

quite

con-

critical

.

Operation

the

.

the

for

the

of

2-

3

Operating

Instructions---Type

7A22

GENERAL

Trace

the

Drift

The

environmentinwhich

inherent
drift.Therefore,todetermine
vironment
in

which
as an
not

Input

When

urement

where

input

refertothe

the

air-conditioned

exceed

Gate

using
with

the

source

gate

OPERATING

characteristicsofthe

Specification

ambient

temperature

building) the

in

101tV

one

hour

Current

the

.1

mV/DIV

an

AC

coupled

impedance

current

should

be

INFORMATION

the

Type

Type

trace

Section.In

does

trace

.

to10ttV/DIV

input,

is

high

checked

adjustedtozero.Thisisparticularly

peratures
Check/
procedures

Voltage

To

tivity,
the

accomplished
described

When

factor (10
an
smalltomake
tion
of
item6of

Where
AC
GND-DC
circuit
permits
voltage
cedure

a.Before
ingaDC
switchtoGND.Then
test

b.Allow about
charge

b
remain
uredinthe

d.On
DC

The
other

(above

Calibration

40°C).Steps7and8in

Procedure

for

setting

Measurement

obtain

accurate

itisnecessarytoground

amplifier

unknown

factor.If

current

and

.

.

Set

switchtoGND

signal

just

before

by

adjusting

under

operational

measuring

V/DIV)

DC

when

voltage source.Then,ifthe

the

measurement,

the

input

might

flow

First

Time

Operation

only

the

AC

DC

components

switchestotake

incorporated

the

coupling capacitortochargetothe

when

for

using

the

in

AC-GND-DC

this

circuitisas

connecting

component,

one

.

the

input

usual

coupling

screen

manner

on

the

completionofthe

and

above

procedure

withadifferentDClevelisconnected

describe

the

gate

currenttozero

DC

measurements

the

making

the

the

STEP

adjustment

voltages,

first

use the

connecting

switchtoa

stageisoverdriven,alarge

into

the

input.See

.

component

istobe

ofasignal

measured,

advantage

the

unit.The

switchissettoGND.Pro-

follows

the

Type

7A22

set the

connect

second

AC-GND-DC

the

inputtothe

for the

switchtoAC.The

and

the

AC

component

.

measurement,

short

the

input

should be

followed

CAUTION

If

the

Type

7A22

is
age
sion,

source

the

without

peak

connected

using

charging

to

the

current

7A22isoperated

7A22

influence

drift

foraspecific

environment

not

vary

generally

ranges

DC

measurements

allowed

at high tem-

the

Performance

check

much

for

MQ)

and

drift

for

(in

excessof1

and

desired

the

.

at

maximum

input

and

DC

balance

measurement.This

ATTEN

DC

number3.

largest deflection

the

Type

7A22

deflectionistoo

lower

CAUTION

having

use

the

of

the

pre-charging

pre-charging

DC

:

toasignal

input

contain-

coupling

circuit

coupling

capacitor

display

can

be

set

the

AC-GND-

connectortoground

whenever

.

a large

pre-charge

DC

volt-

provi-

(into0.1

and

trace

(such

will

meas-

for,

adjust

sensi-

BAL

deflec-

amount

after

both

AC-

circuit

source

under

will

meas-

al`

en-

the

as

an-

capacitor)
source,
stroyed

When

7A22

with

tor

acquiresacharge

as a

low

very slowly
sequent

and

drive

utes,

with

reasonable

may

be
connectors are
ess

will

will

and

this

.

a

large

DC

the

inputACcoupled,

voltage,

decaying

AC

coupled

the

trace

input

settoGND,

recovery from

necessary

shortedtoground

require

less

be

limited

source

voltage has

may

only by

be

been

the

duetodielectric

high

impedance

output voltage.This

measurements

off-screen.A

period

should

polarization,

for

critical

measurements.If

the

time

.

the

damaged

appliedtothe

input

coupling

polarization

voltage source

can

offset

at

other

DC

of at

least

be

allowed

and

a longer period

depolarization

signal

or

de-

capaci-

and

with

voltages

10 min-

to

assure

the

Type

acts

a

sub-

input

proc-

or

Signal

connectors
pling
sometimes
source,
is
of
portant

is

transporting

to

.

test
normally

mon
ference

stray
can
single-ended
cussed

ing
istics
circuitofthe

can
ground

may
In
loads
them

capacitive
measurement
ally

tenuation

special-purpose

Field

puttothe

'The
to
the levels
Voltage

rejection ratio

to

to

When

that

particularly

monitored

these

to

Input

connecting

Connectors

signalstothe

on

the

Type

willbeused.Ordinary

be

usedtoconnect

when

at a

low

factors

use

are

shielded

leads should

When

establish

and

In

some

ground',

magnetic

also

making

the
used

by

be

a

Type

for

cases

and

ground

minimized

single-ended

common

7A22.The

this

differential

therefore

loop

coupling

measurement.These

laterinthis

It is

always

and

resulting

due

normally

paralled

increase

many

cases, the

may

through

Attenuator

to

be

section

importanttoconsider

changeinthe

the

signal-transporting

Type

7A22.The

be represented by a1megohm

by 47pF.Afew

the

parallel

effectsofthese

too great

the useofan
probes

loadingofa

range

of

higher voltages.Passive

factors

of

10X,

types

EngineerorField

Some

measurement

Type

DC

plus

the

peak

chassis

potential

listedinSectionIunder

characteristics.Higher

and

situations

7A22

AC

exceed

-{-INPUT

7A22,

consider

unshielded

the

Type7A22

a

high

impedance

level,

point.However

missing,itbecomes

signal

cables.In

be

keptasshortaspractical

input

measurements,

ground

purpose

shield

.

between

of a

measurements

are

less

currents.Some

into

the signal

by

usingadifferential

considerations

under

Differential

the

source operating

circuitatthe

feet of

capacitance

resistive

anditmay

be

attenuator

not

only

decrease

signal

source,

the

Type

7A22

attenuator

and

are

Office

100X,

available

1000X,aswell

through

.

requireahigh-resistance

with

very

little

source loading or

-

voltages
of

the

the

--------------------

on

the

Type

7A22

Maximum

levels

will

input

degrade

voltage

and

---INPUT

the

method

low-frequency

test

to

of

leads

a

cou-

signal
signal

when

increasingly

all

cases,

the

signal-

.

be

sure

the

device

coaxial

require

under

cable

no com-

susceptibletointer-

problems

transporting

rather

with

leads

than

are

Operation

signal-source

.

load-

character-

leads

and

the

input

input

connectors

resistance

to

shielded

100

and

pF or

capacitive

cable

more

desirabletominimize

probe

.

the

but

to

resistive

also

include

probes

your

extend

substanti-

having

other

as

Tektronix

and

-

test

points

with

should

Common-mode

the

ratingofthe

limited

be

common-mode

unit

respect

Input

.

can

any

im-

is

dis-

to

.

the

at-

in-

sig-

to

2-4

nal

attenuation.In

probe

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by

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vision of

High

The

coupled

/AV

no
internal
input

The
wire
nal
videaDC

the

Type7A22

Input

high

positionsofthe

input

resistance

high

strap

gate

Impedance

input

signals

attenuatorisused

gate

return

.

input

(see

Fig.2-3)

return

path

such a

probeorthe

.

impedance

which

permit

VOLTS/DIV

resistor

impedance

resistance.The

for the

alone

between

FET gate

situation

this

high

provision

the

useof10

switch,

at

these

establishes

is

obtained

the

signal

current

a

passive

problem

input

applies

(DC

switch

by

input

line

source must

.

attenuator

may

be solved

impedance

only

mV

coupled).Since

positions,

the1megohm

unsoldering

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to

through

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then pro-

pro-

DC

the

the

inter-

Operating

Display

Single-ended

or

going
deflected
the

chosen,
as

10

shown

Deflection

The

determined
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factors

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The
vides
between
trol
volts/div

Polarity

signals

-INPUT

trace

connector

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upward,

to

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input-to-display

previouslyinFig.2-l

canbeapplied

.

If

input

and

negative-going

deflected

polarity

Factor

amount

probe,

indicatedbythe

VARIABLE

rangeofthe

uncalibrated

canbesettoextend the

of

by

the signal

the

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controlispushed

the

fixed

.

trace

deflection

settingofthe

VOLTS/DIV

VARIABLE

deflection

settingsofthe

control.The

Instructions

the

+INPUT

signal

will

downward

relationship

.

amplitude,

VOLTS/DIV

"in"tothe

controlisat

factors

VOLTS/DIV

deflection

to either

is

cause

changes

.Ifthe

produced

the

attenuation

calibrated

switch

apply

least2.5:1.Itpro-

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Type

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will

-INPUT

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byasignal

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deflection

only

CAL

IN

the

full

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7A22

-}-INPUT
positive-

cause

reversed

factor

the

and

when

position

range

con-

least

25

is

is

.

Fig.2-3

.

return

picoamperes,
upon

anceisthereforeanimportant
produceaDC
current
may

concern

signal-source
between

input

impedance

Locationofwire

resistor

.

The

uncompensated

the

operating temperature.The

through

resultina

.

When

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are

disconnected

DI

V

to10VIDI

The

high-frequency

the

source

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(see

but

offset.For

significant

wire

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Fig.2-4)

may

10

strap

gate

be

example,a100

megohms

error

straps

are

.

The

deflection factorinthe20m

range

V

response

since

and

the

charge

.

between

currentistypically

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input

line

times

signal-source

factor

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producesa1

where

small

higher

gate

picoampere

NOTE

removed,R111

willbeincorrect

will

various

7A22

inputaswellasthe47pF

and

also

depend

shunt

discharge

.

and

internal

less

than 100

depending

current

mV

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voltages

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R211

upon

capacitances

through

gale

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Vl

the

that

Noise

To

reduce

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the

VOLTS/DIV

50

positions

~tV

gested

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the

to

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ably

distort
tion.RefertoFig.2-6
settingofthe

Bandwidth

In

additiontothe

many

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the

bandwidth

and

HIGH

of

the

7A22

-3

dB

pointsofthe amplifier.The
selector
proximate

and10kHz.RefertoFig.2-5.The

selector controls
100Hzin

frequency
to

ample,
the
considerably
(see
be
the

HIGH
to

amplifier

provides

Fig.2-6

Varying

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high-frequency response

Fig.2-7).Likewise,

filtered

unit.When

FREQ

distort

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or

the

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the

desired

HIGH

Selection

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-3

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obtain a

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using

the signal

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bandwidth

featuresofthe

for

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differential

signal

the

unit.The

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POINT

the

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low-frequency

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high-frequency

sequence
falls

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without

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waveforms

-3

setting

high

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Hz,1Hz,10Hz, 100 Hz,1kHz,

.Beyond

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the

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the

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signal

under

frequency

POINT

rejectionofunwanted
canbeattenuatedbyvarying

LOW

selectorsonthe

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HIGH

rolloff

Type

noise

can,inmany

distorting

line-frequency

low-frequency

FREQ

care

by

rolloff

selector

FREQ

-3

and

high-frequency

FREQ

-3

FREQ

-3

from

the-3dB

octave

7A22isuseful,

signal.By reducing

the

desired

-3

dB

mustbetaken

overly

restricting

not

appreci­observa­for

.

signals,

dBPOINT

front

panel

POINT

dB
or to

dB

POINT

1

MHz

points

rate.Refer

for

cases,

signal

signals
response
POINT

when

and

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each

ap-

the

ex-

can

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the

to

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of

REV.B,

FEB

.

1975

2-5

Operating

Instructions---Type

7A22

2-4A.7A22CMRR

Fig

.

at10IV/Divto10

mV/Div.InputsDCCoupled.Worst-case

degradation

duetosource

resistance

.

Operating

Instructions---Type

7A22

Fig.2-4B.7A22

Bandwidth

and

VOLTS/DIV

Errorasfunctions

of

Source

Resistance

.

Z-7

Operating

Instructions-Type

7A22

Fig

.

2-5.7A22

FREQUENCY

RESPONSE

2MB

asafunction

of

LF ---3dBPOINT

SETTING

(HF

---3dBPOINT

at

1

MHz)

.

Operating

Instructions---Type

7A22

Fig.2-6.7A22

FREQUENCY

RESPONSE

as

a

functionofHF

.--

.3

dB

POINT

settings

(LF

--3dBPOINT

of

DC)

.

2-

9

Operating

Instructions--Type

7A22

Fig.2-7.Improving

(A)

Lower
QUENCY
UPPER

Voltage

Some

than

One
ratio

To

putofthe
ABLE
settings
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bers

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Comparison

applications

the

fixed

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Type

control

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than

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FREQUENCY,

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designate

Differential

Differential

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Then,

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signalstothe

both

AC-GND-DC

signal-to-noise

dB

FREQUENCY

Lower

selectortoDC,

-3

dB

10

kHz

.

Measurements

requireasetofdeflection

values

provided

is

comparison

by

absolute

this,

applyareference

7A22.Set the

throughout

VOLTS/DIV

large

voltage

the

subsequent

switch

ratios.In

VOLTS/DIV

the switch

.

Operation

voltage

or

measurements

DC,

depending

-1

-INPUT

switches

ratio

by

setting

UPPER

FREQUENCY

-3

selectortoDC,

factors

by

the

VOLTS/DIV

of

signal

amplitudes

.

signaltoeither

switch

comparisons.The

canbechanged,

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so,

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positionasratio

are

made

by

and

---INPUT

connectors

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on

the

method

bandwidth

dB

switch

and

VARI-

however,
the

factors

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FRE-

other

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same

coupling

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signals
and

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The

Type

to

eliminate
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information
loop

currents

test

.

In

voltage by
itor

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tationsofsingle-ended
in

differential

A

differential

of

the

input

to

of

the

The

abilityofthe
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This

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lower

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puts.To
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Hz

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attemptismade
VOLTS/DIV
produceadeflection
useful

information

If,

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greater than

common-mode

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.

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mode

rejection.The

jectionisfor

FET

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0

.01

%

in

reduce
in

source

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not

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have

.

ratioto100:1or

Outside

can

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level

signals

minimized

same

typetothe

gether

throughout

Care

signal

transporting
presenceofa
that

lead.Where

avoided,

be

minimized

.

most

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similarly
a

twisted

desired.When

only

the

(signals

that

rejected

7A22

interfering

using

voltage

and

displayedonthe

are

common

(see

differential

signals

the

difference

Fig.2-8)

input

measurements

because

between

other

means
would

of

the

cases,itmay

other

than

limit

low-frequency

interference

oscilloscope

be

desirabletoeliminateaDC

the

use of a

measurements

measurements

measurement

two

inputstoselected

the

amplifier

two

selected

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Type

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thenbethe

7A22

.

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(see

Fig.2-9)
to

common-mode

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100,000:1at

factors

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[kVto10

between

show

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100

kHz

the significanceofthis

input

signal

volt

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the

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1

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the60Hz

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signal

signal

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will

principal

signalismonitored

appear

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same

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the

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mostoftheir

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leads, as

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.

Type

.7A22

for

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in

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provision

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AC

often

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reject

common-mode

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mV

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characteristic,

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to

5000

signal

hundred

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60

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common-mode

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of 5

for

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difference

input

Likewise,

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transporting

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differential

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frequency

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line-frequency

unsatisfactory

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the

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.

.

2-10



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

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Operating

Instructions--Type

7A22

Fig.2-8.Waveforms
signals

.

DC

Offset

By

using

the

Type

7A22

differentiallyina

small

signal

whose

able.The

---1

V when

offsetiscontinuously adjustable

the
positions.In
VOLTS/DIV

the

input

marizes

for

all

the

input

for the

switch,

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the

effectiveDCoffset

the

VOLTS/DIV

attenuator

various

VOLTS/DIV

10

tkV

to10mV

20

mV

._

to0.1V_

0.2Vto1
2

to

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each

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showing

Operation

DC

OFFSET

DC

VOLTS/DIV

the20mV,

the1V

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VOLTS/DIV

setting

V

V____

.__

.

voltsisthe

differential rejection of

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slide-back

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50

switch

mV

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range

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switch

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into

switch

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TABLE

OFFSET

=±

-4-

2-1

10

100
1000

maximum

RANGE

V

-

V

V

2

a

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mode,

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the

101Vto10mV

.1

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positionsofthe

multiplied

Table

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internally

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table

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amplifier

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ATTENUATOR

1

x
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loo

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signal

common-mode

observe

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by

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sum-

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in

X

voltage

to

signal.Resultant

Using

theDCOFFSET

Set the

waveform

Type

VOLTS/DIV
VARIABLE

POSITION

AC-GND-DC

.f-

(-

and

HF

---3dBPOINT

.--3

LF

dBPOINT

STEP

ATTEN

1.Position

convenient

the

reference

2.Connectacoaxial

--f-INPUT

3.Set

.

the

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ure theDCleveltobe

4.Set the

offset

step3.

5.Set

VOLTS/DIV

range

which

See

Table

theLF--3dBPOINT

tc)

shows

functions

7A22

controlsasfollows

(CAL

IN)

--

INPUT)

DC

BAL

tracetograticule

line)

using

cable

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offset

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to

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will

encompass

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front

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:

lo

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Midrange
GND

1

MHz

DC

Adjusted

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from

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panel

selector

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forDCbalance

center

POSITION
the

signal

switch

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DC

level

color

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and

DC

factor

measured

bands

.

the

.

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.

two

other

in

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in

Operating

Instructions---Type

7A22

If

switching
controls
into
able
present

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NOTE

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the

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changedinthe

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mode

7A22

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light

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Overdrive

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INPUT

OVERDRIVE

the

input

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circuitifthis

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INPUT

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The

INPUT

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In

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.

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.

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signal

could

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measurements

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indication

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gain

INPUT

OVERDRIVE

to

continue

:

theLF----3dBPOINT

signals

in

Table

the

AC-GND-DC

1000V(either

by

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the

low

OVERDRIVE

and

lighting

the

overdrive

conditions
input

input

:

signal

(see

Section1for

protective

remainonevenifthe

.

circuit

Indicator

7A22

Type

2-1

probe)

the

exceeds

malfunction

Readout

If

the

Type

7A22istobeusedinan

readout

out

Divider

with
system,

on

whichisconnectedtothe
allows
tion

deflection

probes

the

and

the

VOLTS/DIV

The

-+-INPUT

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factor

capabilities,

factor
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instrument,

the

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main-frame
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readouttodisplay

probe

indicator

the

should

turnsonwhen

differential

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maymean

indicator

overdrive

small

7A22

that

calibration

lamp

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the

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made

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INPUT

such

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selectortoDC

may

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.

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input

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frequency

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.

lamp

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input

overdrive

indicator

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differential

tableofdynamic

fuseisblown.In

AC-GND-DC

.

probes

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attenuation

the

sensing capability

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willbedisplayed

connectors

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switches

oscilloscope

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cific

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Simplified

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.

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pled
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Attenuators

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manual

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the

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all

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onlyinthe

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the

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.

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whole

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DESCRIPTION

Pullout

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connector

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AC

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attenuators.Common

matching

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common-mode

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VOLTS/DIV

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3)

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plifiers
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from a
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preamp

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cuit

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in

factors
openifthe
at

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resistance
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When
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pling

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preamp

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The

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components
amp

to select

10 Hz,
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direct-couples

preamp

connected

gainisapproximately15.

supply

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voltages

common

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inputisequipped

from

10,uV/DIV

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voltage

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through

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opens

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preamp

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push-pull

FREQ

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of

100

Hz,1kHz

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power

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through 10

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circuit

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too

the

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FREQ

than

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or

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preamp.If

detector

approaching

front-panel

resulting

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capabilities

circuitisprovidedtoindicate

from

(variable)

.

-3

outputofthe

the

coupling

the

low

frequency

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the low

preamp

withanoverdrive

ATTENUATOR

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DC

indicating

dB

selector.The

frequency

to

signaliscoupled

identical

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two

amplifiers

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rejection

clamping

Y16

largeaninput

the

same

diodes.For
mV/DIV

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to

the

clamps

mV

positions

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to

surge

dB POINT

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on-screen

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lamp

signals

containing

allows

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time

feedback

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ratioofthe

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input

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the

inputtoa

signalisap-

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the

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differential

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differential

lights

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out

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Point

preamp

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positionofthe

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Fig.3-1.Generalized
input

Description-----Type

Amplifier

The

signal

from

the

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similar

changes

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output

Output

the

.

7A22

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amplifier

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the

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VOLTS/DIV

relation

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between

High

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--

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the

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1

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justabletoset

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provided
lector

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10 kHz,30kHz,

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amplifier

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gain

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GENERAL

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Since
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is

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this

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Amplifiers

the

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3-1

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a generalized

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3

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Switching

following

switches

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to

and

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is

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equaltothe

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the

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the

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high

300

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Since
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the

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in

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From

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nearly

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lookingatthe

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input)of10

the

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input

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will

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R1_

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differential

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connected

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.

description, the

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any

differential

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signal

system

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modifier

modifier outputis1

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the

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primarily

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amplifier

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input

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the

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to

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base

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DETAILED

Input

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pling

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through

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ternally
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removing
signal

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also

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the

.

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avoided

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FETs

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Fig.3-2toavoid

operationofthe amplifier

CIRCUIT

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appliedtothe-f.

internally

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the

from the

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the

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for the

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the

the

ground

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when

level

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AC

input

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circuit

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X`15

signaliscoupled

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reference

C101

S101isswitchedtothe

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Description-Type

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used

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in

lossofsignal

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DESCRIPTION

Schematic

input

connector

preamp

the

AC

C101,

and

amplifier.The

input

for the

otherwise

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amplifier

under

disconnecting

thereisno

.

test,

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rather

than

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current

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remains

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1

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the

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directly

the

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since

to

the

input

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DC

component

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position

amplifier

charging

the

in

the

AC

loading

normal

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current

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.

the

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produce

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setting

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pacitor

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To

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To

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panel

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conjunction

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In

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The

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input

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negative

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sensing

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by

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by

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with

the

selected

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.

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reactanceofthe

frequencies

frequencies,

and

the

divider

to

providing

within the

are

designed

the

VOLTS/DIV

to

provide

Current

be

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an

FETs

the

elements

voltage

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removed

frequencies,

correct

Compensation

current

as

high as

1

offset of

may

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supply

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overdrive

approximately

this

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.

across

gate

currentatincreased

the

current

compensation

vertical

megohm

associated

for

Amplifier

input

two

amplifier

identical

feedback

7A22

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still

functions

VOLTS

in

positions

into

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deflection

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attenuator

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bandwidth

associated

100

be
variable

voltage

increase,aiemperature

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circuitinthe

seenbythe

in

the

deflection

/DIVswitch,

the

gain switched

the source

2)for

the

gain

frequency-compensated

frequency

(e .g

.,

by
capacitors

that

the

08C, CI 08D)

constant

to

in

switch.Each

.

input

100pA.

to

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protection

R111

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gate

high

input

amplifiers

resistor

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above

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input

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switching

factors

R108C, R108D)

the

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their

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reactanceofthe

becomes

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maintain
parallel

C108C)

and

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This

ground,

at

this

to

zero

controls

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Fig.3-4)

with

the

diodes

doubling

and

R211

temperatures,anequal

the

thermistor

level

becomes

impedance

Type

connectedina

same

factor

mV,

.

signals,

in

attenuation

instrument,

the

with47pF)

to

adjustable

the

high

effect,

R115

using

increases

at zero

signal

source.The

manner

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the

amplifier

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positions

input

resistors,

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ratiointhe

the

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is

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primarilyacapa-

.

same

attenuator

provide

.

gates

100pAof
R111

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and

.

gates of

increases

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sensitive

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gainofthe

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10,uV

attenuators

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voltage

they

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the

voltage

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at

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the

input

input

for

contains

correct

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the

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leakage

R211)

sensitivities

the

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R215

to

the

input

rapidly

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10°C

input

duetoin-

.

.

differ-

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high

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each

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up

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is

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to

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RC

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.

Fig.3-4

.

Gate

ential

configuration
supply
amplifier
strappedtothe
the
providedinthe

conductorsifa
the

to
component

signal
"Q",
C215,

inputs
in

feedback

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Q144A,
resistor

fier,
termined

base-emitter
total
R133,

nected

against

stabilize

is

voltages (except

are

CMRR

input

.

Any

amplifierofthis

the

input

source

the

amplifier

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X15

Preamp.The

are

identical

a

coupled

amplifiers

In

the

actual

consistsofthe

0153,

R159

and

the

by

Diode CR131

voltage

R233

between

reverse
the

DC

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balanced

of

of

circuitatthe

by

Current

Compensation

with

at

obtained

the

input

large

element,islikely

impedance

impedance

compensate

differential

circuit

feedback

.

R151isthe

approximate

dividing

is

junctionsofQ144A

across

constant

base-emitter

base-emitter

R258,

from a

common-mode

amplifier.Input

circuittoprevent

overdrive

type,inwhich

at higher

is

could

for

feedback

except

mode

.

(see

comparator

modifier

gain

gainofthe

R159byR151,

used

for

the

input

with

temperature

higher

DC

levelatthe

STEP

ATTEN

.

a

push-pull

the

output)

power

supply

input

signal

overdrive

damage

is

inadvertently

the

to

exhibit

a negative

frequencies.If

inductive

oscillate.C115,

this

for

Schematic

temperature

of

withasufficiently

negative

amplifiersinthe

circuit

numbers,

as

described

1)

Q133A,

R151,

R153

setting

resistor

amplifier

(--R°-)

R

;

compensation

and

Q144B.This

stage

current-setting

.

Q144A,

breakdown.C144

frequencies

protects

outputofQ153,

DC

BAL

output.The

for

each

feedback

that

This

protection

to

applied

R117

resistance

+

and

+

error

output

for

the

can

keeps

CR144

the

transistor

and

STEP

is

improves

the

resistance

the

operate

feedback

amplifier

resistors

ATTEN

.

feedbackistaken

R116,

input

previously

the

and

.

Diode

.

.

The

power

boot-

semi-

input

high

and

and

under

load

ampli-

be

of

con-

C244

Q253

is

to

.

--

de-

the
the

3-

4

Circuit

Description----T

e

DC

BAL

control

changes

by

changing

the
ferenceinpotential
(pinsZand
GND

With
stray
current
is

adjusted

frequency

Floating

X15preamp

regulators,

W)

and

the

high

capacitance

into

the

to

range

Power

are

VR305,

LOW

frequency

two

equalize

Currentissuppliedbytwo

the

current

DC

balance.Itisused

across

to

zero with

FREQ

---3dBPOINT

common-mode

of

the

X15

output

these

over

which

Supply.The

obtainedfrom

VR320

and

current

the

outputofthe

the

input

preamp

linesathigh

currents,

useful

a chainofZener

VR325

Fig

3-5.Common-mode

through R257,

to

coupling

switch

signals

can

inject

frequencies.C330

thus

CMRR

can

supply

voltages

connected

sources,

Q304

R259,

adjust

X15

switches

settoDC

the

undesirable

extending

be

obtained

for the

diode

in

and

there-

the

Preamp

wiring

shunt

series
Q324

Rejection

dif-

at

.

the

.

.
.

using

floating

C307,
creases

Any

fier,

exceptatthe
through
maintained

power

C317

and

the

bootstrap

common-mode

Q314.Q314

very
presentedtoits
Q304

and

Q324,

Common

Mode

tionsoftheX15
ponentinthe
In

the

extreme

voltage

and

would

applied,

actually

supply

C325

output,

close

output

thus

Rejection.One

preampisto

input

signals,

case of

the

outputofthe

be zero

.

filter

out

the

stabilityathigher

changes

isanemitter

achieving

the inputs

are

to

unity

by

the

and

that

occurinthe

coupledtothe

follower

by

high

collector

good

reject

any

amplify

tied

together

amplifier

provided

Zener

frequencies

the

minimum

bootstrap

of

the

common-mode

only

that

the

noise.C315

.

input ampli-

power

supply

whose

gain

loading

impedance

efficiency

primary

func­com-

the

difference

andacommon

is

ideally

zero,

characteristics

3-5

in-

is

of

.

.

Circuit

Description-Type

TA22

+0.5V

+1

V

+0.5V

of

all

corresponding

fier

(see

Fig.3-5)
mismatch
matching,

will

thereisstillacommon-mode

sultinginan
the

subsequent

The

floating
improve
fier
3-5).It
amplifier
and
where
Q153
match

3-6

the

CMR.Suppose

connectedtothe

is

can

be

moves

thatnochangesinvoltage or

within the

and

Q253

of

importanceisthat of

elementsonthe

were

causeadifferential

undersirable

stagesofthe amplifier

power

supply

seen

that

an

amount

amplifierasa

draintogate

two

exactly

matched.In

output.Even

common-mode

eliminates

the

inputtothe

junctionofR151

now

the

entire

equaltoVcm

current

resultofVcm,

voltage.Thus

Q153,

+0.5V

Fig.3-6.Input

sidesofthe

practice

output

signal

(common

difficulties

these

bootstrap ampli-

and

R251

power

(ie:follows
levels

the

Q253

amplification

with

current
applied

mode

(see

supply

occur
except

only

ampli-

any

perfect

re-

to

gain)

and

Fig

and

Vcm)

any-

for

mis-

cross

neutralization

factors,
point
only a

from

.

inject
mon mode

3-5

power

.

justable currents

ize the net
common

over

power

+0.5V

.

and

of relatively

small

At

higher

various

significant

Schematic

or

supplytothe

mode

which

beinginthe

degradationinCMR

frequencies
pointsinthe

current

signals.The

10

into

output

signals

useful

CMRR

third

large

differential

the

X15

into

differential

)

connected

two

output

the output.It

currents

and

so

canbeobtained

Cross Neutralization.The

supply

resultsinan

4

mA

stageofthe

signal

amplifierata

level,

.

inevitable stray

preamp

the

amplifier

to

as a

ground

capacitances

resultofcom-

capacitor

from a

pointinthe

lines,isusedtoinject

canbeadjustedtoequal-

resulting

extend

from high

the

rangeoffrequencies

.

useofa

common

undesirable capacitive

this

causes

begin

C330,

floating

frequency

bootstrap

coupling

(Fig

ad-

to

.

U



between

volt to

Fig.3-6)

and
age
operating
cifically,
a
and

-input
which,

nal

its
C241, connected

justtodivert

tralize

zero.R141

-I-input

andB,being

large

tectionisa
tection

the
grounded,

mately

voltageonthe
sequence
can
present,
current

creasing
is

Fig.3-7.Effectsofhigh

the

two

the

-¢-input

.

The

results

are
(b)ashiftofall
levelsby+0.5V

into

the

the

drain

current

into

i,b

the

and

through

---input.If
ground,

being appliedtothe

+input

Note

output

that

the

and

causesanerroneous

the

end

(Q253

i,b

effect

and

.

Input

Overdrive

semiconductors

overdrive

necessity

system

usedinthe

There

are

equal

Assume

two

7A22,

and

(b)

input

the

Type

(a)

-}-input.The

of

events:F119

supply 1/16

the

+input

flowing

Now

to

assume

,---voltageonthe

showninFig.3-8C

+INPUT"

inputs.Consider

(a)anoutput

output

from

away

of

C141

applied

different
(a)

----input

amp

groundasshowninFig.3-8

the

the

effectofapplying

while

keeping

the

---

inputat0

currentof4

supply voltages

duetothe

bootstrapped

of

Q133B

the

draintogate

thereisany

will

i,b

---input

and

divider

power

also

rises+0.5V and

capacitanceofQ133B

impedance

develop

subtracts

several

actionofR151,
supply system.Spe-

a voltage

output

current

flowing

through

source)togoto-0.6V.A

this

pointtothe

from

the

and

Cde

reduce

performasimilar

Protection.Since

input

-input

line(ilb

the

the

--input

input

canbedestroyedbysufficiently

directlytothem,

.

The

important

Type

7A22

components

are

showninFig.3-8A

kindsofoverdrive associated with

single-ended
common-mode
voltages

grounded

overdrive,

overdrive,

.

andasteadily

chartinFig.3-8B

will

openifthe

of

current.If

remains

d-input

---input.The

at

+16

-grounded

this
.5V,

much

with

and

sequence

.

impedancetoground

in

volts

mA,

as

other

between

across

from

the

(see

Fig.3-7)

R253

capacitor,

can

)

and

current

function

FETs

some

input

of

the

with

one

with approxi-

increasing

indicates the

-_h

signal
currentisnot
the

overdrive

.

a

steadily

of

the

-INPUT

+1

(see

shown,

volt-

R251

injects

the

origi-

.

causes

be ad-

so neu-

for

the

Q133A

pro-

pro-

input

source

in-

events

.

Circuit

(b)

For

common-mode

is

essentially

overload,
reaches

paths are

For

differential

-I-

the

plyingi,.
inputs

when

will

not

it

-16.5V
DC

Offset.The

similar,

and

the

approximately

showninFig.3-8A

and

---

single-ended

(In

effect

the

differential

open

until

.

allowadifferential
out

small

DC

components

amplifiertoamplify

keeping

voltage

to

found

illustrates

3-9B

R151,
the

.

the
ing
and5mA

adjustable
Due
101tV
niques

offset

control
tion

the

differential

is

applied

to

balance

how

this

Fig

.

3-9A

shows

shows

the

}-input

.

This

currents

would

R251.However,ifthis1mAissupplied

offset

generator,

Q133A

and

Q133B

currents,

io,

remain

respectively

Offset

Generator.The

balanced

to

the

wide

range

per

div)

stable

which

generator

factors

The

minimize

.

is

usedtoobtain

.

functional

A

showninFig.3-10.In
SET'

control,
voltage
age

(V,a)
R279

(approximately
difference
at

least

This

a

balanced
described
plifier

(also

the

similar
ential

R287,

%ffset",

of

the

When
divider
the

LF --3dBPOINT
range
whose
theX15
input

.

R270,

across

the

is

taken

voltage

---4

Vto_I-4V.

adustable

feedback

previously

"A",

the

output

manner,

input

(V,b-V,,)

R289.The

flows

through

amplifier

the

offsetisnotinuse

(R273,

R277)bythe

with

respect

purposeisto

preamp,

difference

feedback

voltage)

Vzb

resultant

and

overdrives

except

current

--13V.The

overdrive

a 5kQresistorisconnected

one

or

purpose

slideback

only

capability.This

across

out

the

is

done

.

the

standing

with

cause

thennonet

source

at

.

offset

of

components

drift

10

turn

adequate

arrangement

the

reference

taps

an

reference

from

the

50%

of

(VIb---V,,)

amplifier

under

V,,tofollow

follows

is

therefore

the

out

their

switch)

to

V,b

adjust

andtobring

Description--Type

the

clamping sequence

the

X15

amplifier

i,

does

not

flow

fuse

until

opening

does
the

current

.

the

actionisa

sequences,

with

combination

the

---input
across

voltage reaches

both

inputs

of

the

measurement,i.e

of

input

the

varying

the

inputs,

resultant

output

currents

a 0

.25VDC

anio'of1mA

output

currents

their

zero

offset

generator

current

for

the

offset

are

and

noise

coarse

and1turn

resolutionatlow

of

the

voltage

adjustable

Zener

VR270, andafixed

voltage

the

reference

is

adjustable

divider

reach

DC

offset

signals

components,

means

some

for
input

current

and

signal value,2mA

useintheX15

system

used

are

offset

generator

portion(Vlb)of

voltage);thus,
over

The

3V).

+16

.5V

systemisto

. :tobuck

and

allow

that

whenaDC

means

must

current.Fig.3-9

zero

input.Fig

appliedtothe

to

flow through

as

shown

results.Both

the

output

produces

preamp

(200,000

and

div

circuit

employed

fine

OFFSET

deflec-

generator

the

formed

the

by

range

voltageisappliedtothe inputs

conceptually

differential

action

forces the

in

amplifier

V,b

reproduced

current,

­R287+

FET (Q273,

drainstothe

V,b

OFFSET

by

out

ON/OFF

.

V,isadjustable

the

COARSEDC

any

its

outputtozero

V26_

is

initialDCunbalance

similartothat

configuration.In

the

---input

-+input

voltage

V,,.In

"B".The

across

resistors

-V2a
R289

Q283)

X15

'

output

preamp

whichis

switchedtothe

switch

(part

overasmall

BAIL

control,

with

stages

7A22

not

input

of

sup-

the

fuses

or

the

while

be

by

stand-

the

at

tech-

in

the

is

OFF-

the

volt-

R271,

the

of

of

am-

a

differ-

.

fixed

of

in

zero

.

.

Circuit

Description---Type

7A22

+Overdrive

-Overdrive

path

path

Fig.3-8.(A)

In

the actual

modified by

which

changes

potentiometer
nectedtoeach

filters

out

Zener

The

feedback

Q273

and

Q264B,

put

appliedtothe
feedback
ating

to

current

circuit,

the

additionofa

the

effective

means

by

end

noise

Overdrive

of

from

the

of

the

Protection

reference

range

two

COARSE

the

amplifiersAandBare

respectively,

Q283

emittersofdual

its

bases.Current source

for the

amplifiers

.

FINE

OFFSET

of

voltage

reference

with

transistor

3-8

showing

System

voltage

control

the

10 turn

dividers,

control.A

voltage

composed

the

Q264

Q284

supplies

current

generator

(R265),

COARSE

one

capacitor

.

of

Q264A,

reference

and

con-

in-

the

oper-

paths.(B,

is

C)

Input

Sequence

Overdrive

of

events

Indicator.When

selectorisinaposition
indicationofthe

may

be

driven
ponent,
indicator
warning
of

CR343,
In

its

The

the

leading

detects

light

dynamic

indicator

Q344)

quiescent

DC

non-linearityoroverloadbya

into

erroneous

to

this

that

theX15

range

.

consists ofathreshold

andamonostable

state,

leading

to

other

than

DC,

conditions

the

in

displays.The

condition

and

preampisapproaching

lamp

while no overdrive

excessive

overdrive

the

LF---3dBPOINT

thereisno

preamp,

X15

on-screen

DC

input

overdrive

indicatesbymeans

the

detector

driver

(Q334,
exists,

.

and

com-

of

limits

(CR341,

Q354)

CR341,

it

a

.



Circuit

Description----Type

7A22

A

CR343,

R343

detector,

-4-33.4V;CR341

on
R333,

turns
on
turns

Q334,

new
through

off
other overdrive

to
flashesatapproximately
high
and

however,aDC
discharge

rent
driveisremoved

frequency

0.1Hzto10
ing the
in

selector,

Q344,

Q334

form a

voltage

Q344,

at

approximately

Now

suppose

Q334

and

on

harder.If

off

.

0354

voltage

R337

for

approximately1second,

about

speed

makes

through

LF

-3

resistor

each

with

one

(or

via

R347.Q334

the

resulting

the

lamp.This

the

However,

and

the

(approximately

exceeds

signal

10

kHz),

AC

effectively

the

circuit

overload

does

not

R347.Thus,

.

clB

POINT

--3dBpointofthe
kHzindecade

and

legofthe

the

switch

CR343)

overdriveisremoved

the

turn

capacitorofa

Fig.3-9.Offset

and

Q354

divider

of

theX15

negative going

causes

the

current

lamp

thatinR349,

. .

Thus

monostable

a 2

actasifithadaDC

Q334

Selector.This

amplifier

splitupinto

are

to

set

the

-x-32V.

preamp

and

Q344

collector

chargesupthe

keeps

the

steps

current

currentinR349

through

on

until

C349ischarged

1

second)

R337.This

even

for

repetitive

free-runs

second

rate.(Above10kHz

Q344

off

sinceitis

lamp

stays

amplifier

.

Selectionisdoneby

pair

.

Fig.3-11

its

system

showing(A)

all

cut off.R341

emitterofthe

output

collector

turnsonQ354

step

at

immediately,

C349,

and

if

Q344

stray

on,

the

on

switch

and

of

capacitor couplings

shows

functional

threshold

lines

current

Q354

to

turn

R349

the

keeps

receives

overdrives,

and

the

capacitance

overload.)If,

endofC349

kept

onbycur-

until

the

selects

has a

range

half of

elements

Conditions

and

exceeds

turns

via

collector

Q334
Q344

keeps
to

its

current

Q334

an-

(up

lamp

the

over-

the

low

of

switch-

the

B

with

zero

For

the

sistors

R353C,

the

following

-

3dBfrequency

output

resistors

Whenever

C156,

it is

load

resistance

C353A
(0.1Hz,1Hz
coupling.Resistor
C156isusedtocompensate
capacitive
C

5 .

When
be
momentarily

is

the0.1Hzto

rapidly

OUTPUT

Gain

a
preamp

.

accomplishedbyswitching

Switching

The

gain

balanced

but

offset,

(B)0.25VDC

100Hzto 10

R353B

combinations

R353A

placed

seenbyVin constant

switched

and

divider

pre-charged
.

kHz

and

R353A

:

100

Hz

R353C__R35_3__&

or

R353Bisnotonthe

across

the

across

10 Hz)

R157

adds

formed

10Hzpositions

by

AMPLIFIER

Amplifier

switching amplifier
differential

with a

configuration

fixed

R407

offset

.

positions,

input,tokeep

C156

and

a

small

for the

by

switchingtothe10Hz

(See

(Q404,

power

.

C156isused

are switchedtothe

1

kH

R353B

the

.

for

the

C156

loss

C156

lower 3

is

shorted out

incrementingain

of gain through

and

stray

areinuse,

Schematic

Q414,

very

similar

supply.Gain

output
high

capacitance

C353Amay

Q424,

to

switching

and

output

side

frequency

ranges,

for

DC

when

the

position

Q524)

theX15

re-

in

of

is

is

3-

9

Circuit

Description-Type

7A22

Fig.3-10.Functional

Diodes

CR413,

downin0414

the

output

CR417

and

from

swinging

ensuringafast,

and
ATTEN

Q404B,
any

A &B.

BAL
developsasmall

initial

The

CR513

under

overdrive

current

that

can

CR515,

CR517

too

far

from

clean overdrive recovery.The

adjustment

unbalanceinthe

STEP

AC

ATTEN

prevent

(R505)inseries

base-emitter

conditions

through

flow
prevent the basesofQ424,

the

emitter,

preventing

adjustable voltage

gate-to-source

BAL

also

sets

3-10

:

CR419,

Q424,

with

which

voltages of

the

reverse

CR519

break-

limit

Q524.CR415,

Q524

breakdown

STEP

AC

source

the

removes

Q404

voltage

across

arrangement

of

the

offset

of

gain-setting

(gate-to-gate)

VAR

BAL

Q424

and

Q524

The

gain switched
teristicssothat
can

be

used.Itisgain-switched

generator

resistor

voltageiszero

(R425)isused

R407tozero

with zero

amplifier

the

full

.

dynamic

1,000:1withnosignificant
characteristics

.

when

the

differential

.

to

balance

inputtothe

has

the

output

amplifier

excellent

rangeofthe

over a

currents

.

overdrive

input

range

amplifier

of

changeinbandwidthorany

input

of

charac-

about

other

Circuit

Description--Type

7A22

HF

-3

dB

POINT

lector

simply

switches

the

outputofthe

quency
adjusted

--3
in

the1MHz

Variable

The

variable

much

voltage
tions.The
ter
signal
emittertoemitter
a 2.5:1
fine
polates

POSITION

rents

This
velopedinthe

outofthe

plifiers

Signal

The
common
improve
the
sistance,
tate
is

setinthe1mV

R443,

namic

C543

Trigger

The
to

the

justable,
signal

configurationisa

amplifier

currentvs.

range

controlofgaininthe

between

into

the

current

collectors

.

Output

signal

emitter

the

stageisdetermined

whichisadjustablebyGAIN

calibrationofthe

R543

conditions,

are

high-frequency

Output

trigger

signal

so that

output

gain-switched stagetoset

point

dB

OutputStage

output stage (Q434,

gain,

butitperforms a

with

emitter

input

resistance.This

by

the

the

controlisobtained

emittersof0434,Q534,

addstoor

emitter

Amplifier

output

configuration

stability

position

equalize the

thereby

Amplifier

output stage

output

stage,

the

output,

level,

caninfact

INDICATOR

General

The

readout

probe

sensing
signal to
DIV

switch.R618A, R618B,

or 5

depending

R618C, R618D,

device

(Q614)

again

depending

R618E, R618F,
(milli),I(micro),orno

the

block

device.The

Indicator

upon

R618L,

select

on

and

R618N

Selector.The

different

of

valuesofcapacitance

the

amplifier.The

positionbyC425

collector

degeneration,

voltage)

VAR

being determinedbythe

control,

uncalibrated

stepsofthe

subtracts

resistors

into

amplifier

R432,

the signal

(Q444,

with

and

linearityofthe

by

the

instrument.The

of

the

VOLTS/DIV

powerinQ444,

eliminating

by-pass

(Q454,
except

while nominally

have

OSCILLOSCOPE

READOUT

consists of

switching

Oscilloscope

and

R618G

the

combination

and

the

outputofthe

the

decimal

the

switched-in

select

the

sub-unit.R618H

_3

HF

dB

---3dBpoint

.

Q534)

does
number
loaded,

the

gain

resistance

R535,

is

which

position,

VOLTS/DIV

feeding

by

via

from

R535,

and

switch

adjustable

resistors

the signal

R532,

trigger

Q544)isa

emitter

degeneration

circuit.The

total

emitter-to-emitter

control

(R540) to

gainofthe

switch

Q544

thermal

distortion.C443,

capacitors,

Q554)isalmost

the

stage gainisnot ad-

the

quiteawide

switching

resistors

resistors

the

settingofthe

select

the

thatisswitchedin.

probe

point

(number

resistor

Volts

sub-unit,

and

POINT

across

the

high

not

contribute

of

other func-

common

emit-

(collector

adjusted

provides

and

inter-

.

R431,

R531

current

and

flows

output

push-pull

gain

facili-

amplifier

.

under

identical

sameasthe

tolerance

and

are used

VOLTS/

number1,2,

sensing

of

zeroes)

combination

either

R618K

select

se-

fre-

total
over

cur-

de-

am-

to
of

re-

dy-

a

to

m

is

a

.

Fig.3-11.Partial
amplifier

the

symbol

when
position.Refertothe
Switch
tingofthe

Probe

.

.

The

of

the
sensing
through
out

displaysothat

displayed

The
forms
the

-15V

lowing
Q614.The

by

the

When
nector

(detrmined
is

added

A37

.

+35

.

the

to find

Low

V

(volts).R618J

VARIABLE

the

VOLTS/DIV

Frequency

VOLTS/DIV

Schematic

resistors

switch

..».3

dB

and

R618M

knobisin

Diagram

associated

.

Point

select

with a

selector

the

of

the

the

particular

Sensing

probe

sensing

probe

the

amount

the

probe

.

probe

a

voltage

supply.This

current

bias voltage,

probe

the--15Vclock pulseisappliedtointerface

B33,

Q614

by

to

the

connected

of

coding

the

connected

divider

to

flow through

coding

is

the

base

column

device (Q614)

to

the

front

current

flowing

resistance,

actual

probe

to

the

-}-

with

R610

forward

biases

R630,

appliedtothe

resistanceofthe

interrogated

voltage

current

and

and

through

identifies

(or

(R620)

panel

from

and

tip

deflection

---)

the

connector,

the

adjusts

INPUT

through

CR610

reducing

baseofQ614,isset

divider

its

collector

emitter

probe

resistor,

interface

for-FInput

symbol

>

uncalibrated

VOLTS/DIV

set-

attenuation

by

current

sink

the

read-

factor

connector

CR615

(CR620)

the

bias

al-

on

.

con-

currents

R614)

connector

is

to

3-

1 1

Circuit

Description-Type

7A22

Witha1Xprobe

off,

and

the

deflection

termined

of

the

Witha1OX
biason0614
This

increases

byafactorof10

When

to

the

willbethe
For

example:ifaIOX

and

a

will

display
probe
200

/_tA

factor

This

out

will

forasingle

factor,

play only

the

by

VOLTS/DIV

different-attenuation

-}-

and

probe

100X

the

.

The

100X

of

collector

(in

the

means

give

the

probeortwo

whereas

the

plug-in

(ornoprobe)

factor,

settingofthe

switch)

only

probe

connectedtothe

will

allow

100toof

the

deflection

.

----

INPUT

connectors,

tip

deflection

probeisconnectedtothe

probeisconnectedtothe

deflection

probe

will

current

readout

that

display)bya

Indicator

the

correct deflection

probes having

the

VOLTS/DIV

deflection

connected,

the

in

Readout

.

collector

factor

(in

divider

factorofthe

factoratthe

set

the

which

will

factorof100

Oscilloscope

factor

knobon

factor

.

Q614isturned

readout

probes

the

biasonQ614

increase

display,isde-

Switch,

input(+or

currenttoflow

the

readout

are

displayed

larger

--INPUT
tip

of the

the

displayed

the

from

the

same

the

plug-in

(part

S407,

----),

display)

connected

readout

divider

+INPUT

the

readout

10OX

allow

to

deflection

.

read-

probe

attenuation

will dis-

the

tip,

Trace

The

TRACE

things

:

1.It

causes

7A22,tomoveasmall

.

R622,

from
R634.This
causing

R630

.

--1

hard

B33isinterrogated,

the

when

buttonisreleased,

display

system,
manual

the

2.Formsavoltage
and

.5V.

(1,000,

word"IDENTIFY"toappear

These

multiple

.

For

more

.

Identify

IDENTIFY

the

ground

shuntsasmall

tracetomove

R622,

placing

This

low

A

collector

two

actions

traces

specific

refer

to

button,

trace,

representing

amount

through

.

divider

the

value

of

current)

erasing

aid

in

are displayed

the

readoutisrestoredtoits

information

the

appropriate

when

by

inserting

CR630tothe

amount

from

the

baseofQ614

bias

will

when

the

readout

.

identifying

.

on

pressed,

the

outputofthe

a 2

junction of

of

the

output

---15Vsupply
at

approximately

cause

Q614

interface

display

Type

the

When

the

the

operation

Indicator

does

two

Type

resistor,

kQ

R632

and

current

through

connector

causing

trace

IDENTIFY

previous

the

of

on

to turn

and

7A22

Oscilloscope