Tektronix Z User manual

Other manuals for Z

1

Table of contents

Other Tektronix Amplifier manuals

Tektronix

Tektronix 2A61 User manual

Tektronix

Tektronix AM 502 User manual

Tektronix

Tektronix 7A14 User manual

Tektronix

Tektronix 11A32 Assembly instructions

Tektronix

Tektronix 7A22 User manual

Tektronix

Tektronix TPA-N-PRE User manual

Tektronix

Tektronix TYPE CA User manual

Tektronix

Tektronix 80C11 User manual

Tektronix

Tektronix 7a15 User manual

Tektronix

Tektronix 7A18 User manual

Tektronix

Tektronix 3240 User manual

Tektronix

Tektronix 53C User manual

Tektronix

Tektronix 11A52 Owner's manual

Tektronix

Tektronix 2A60 Product guide

Tektronix

Tektronix TekConnect TCA-1MEG User manual

Tektronix

Tektronix 11A32 User manual

Tektronix

Tektronix 11A34 Owner's manual

Tektronix

Tektronix 7A26 User manual

Tektronix

Tektronix 7A24 User manual

Tektronix

Tektronix P6046 User manual

Tektronix

Tektronix 59 Product guide

Tektronix

Tektronix 7A26 User manual

Tektronix

Tektronix 5A15N User manual

Tektronix

Tektronix TYPE L User manual

Popular Amplifier manuals by other brands

Magnat Audio

Magnat Audio EDITION FOUR Owner's manual/warranty document

Inter-m

Inter-m PA-2000A Operation manual

Yamaha

Yamaha TX6n owner's manual

Peavey

Peavey TNT 150 user guide

Bosch

Bosch LBB 1903/10 Installation and user instructions

Avocent

Avocent Emerge DA1200D Installer/user guide

Redgum

Redgum RGi35 operating instructions

Cambridge Audio

Cambridge Audio AXA25 user manual

Alpine

Alpine MRP-M200 owner's manual

Technical Pro

Technical Pro H1502UrBT user manual

FMS

FMS EMGZ307 operating manual

Racal Instruments

Racal Instruments 5601 user manual

Valcom

Valcom V-1094A Technical specifications

Cambridge Audio

Cambridge Audio 851D user manual

QSC

QSC 3800 Specifications

NAD

NAD C300 owner's manual

Rotel

Rotel RMB-1077 owner's manual

Peavey

Peavey Monitor 300 Series operating guide

INSTRUCTION

MANUAL

Tektronix,

Inc.

S.W.

Millikan

Way

•

P.

O.

Box

500

•

Beaverton,

Oregon

•

Phone

Ml

4-0161

•

Cable .-

Tektronix

Tektronix

International

A.G.

Terra enweg

1A

•

Zug,

Switzerland

•

PH.

042-49192

•

Cable:

Tekintag,

Zug

Switzerland

•

Telex

53.574

070-251

WARRANTY

All

Tektronix

in trument

are

warranted

again t

defective

material

and

workman



hip

for

one

year.

Tektronix

tran former ,

manufactured

in

our

own

plant,

are

war



ranted

for

the

life

of

the

in trument.

Any

que tion

with

re pect

to

the

war



ranty

mentioned

above

hould

be

taken

up

with

your

Tektronix

Field

Engineer.

Tektronix

repair

and

replacement-part

ervice

i

geared

directly

to

the

field,

there



fore

all

reque t

for

repair

and

replace



ment

part

hould

be

directed

to

the

Tek



tronix

Field

Office

or

Repre entative

in

your

area.

Thi

procedure

will

a ure

you

the

fa te t

po ible

ervice.

Plea e

include

the

in trument

Type

and

Serial

number

with

all

reque t

for

part

or

ervice.

Specification

and

price

change

priv



ilege

re erved.

Copyright

©

1960

by

Tektronix,

Inc.,

Beaverton,

Oregon.

Printed

in

the

United

State

of

America.

All

right

re erved.

Con



tent

of

thi

publication

may

not

be

repro



duced

in

any

form

without

permi ion

of

the

copyright

owner.

Type

Z

Warranty

Section

1

Specification

Section

2

Operating

In truction

Section

3

Circuit

De cription

Section

4

Maintenance

Section

5

Calibration

Section

6

Acce orie

Section

7

Part

Li t

and

Diagram

p://manoman

Type

Z

CONTENTS

Type

Z

ON

1

SPECIFICATION

S

General

Information

The

Type

Z

Plug-In

Unit

i

a

calibrated

differential

com



parator

preamplifier

de igned

for

u e

in

all

Tektronix

Type

530-,

540-,

550-,

or

580-Serie

O cillo cope .

The

unit

may

be

u ed

for

three

different

mode

of

operation:

(I)

a

a

conventional

plug-in

preamplifier,

(2)

a

a

differential

input

preamplifier,

or

(3)

a

a

calibrated

differential

com



parator.

A

a

conventional

preamplifier,

the

Z

Unit

alone

ha

a

ri etime

of

24

nano econd

and

a

maximum

en itivity

of

0.05

volt

per

centimeter

of

deflection.

Table

1

-

1

ummar



ize

the

ri etime

and

bandwidth

available

when

the

Z

Unit

i

u ed

in

combination

with

variou

type

of

Tektronix

o cillo cope .

TA LE

l-l

Z

Unit

and

Ri e

t

ime

in

Bandwidth,

—

3

d

B

,

Type:

Nano econd *

Megacycle /Second*

532

70

5

531

or

535

39

9

536

40

9

531

A,

533,

or

535A

35

10

541,

543,

545,

541

A,

545A,

551,

or

555

27

13

581

or

585**

27

13

*For

ignal

which

do

not

over can

the

graticule.

**Type

81

Adapter

mu t

be

u ed.

In

differential

input

mode

of

operation,

the

dynamic

range

of

±

1

00

volt

allow

the

application

of

common



mode

ignal

up

to

1

00

volt

to

be

applied

to

the

unit

with



out

attenuation.

The

common-mode

rejection

ratio

of

40,000

to

1

at

d

c

or

low

frequencie

allow

mea urement

of

differential

ignal

le

than

50

mv

in

amplitude

on

±100-

volt

common-mode

ignal .

A

a

calibrated

differential

comparator,

the

Z

Unit

ha

an

effective

creen

height

of

it

2000

cm

at

maximum

en i



tivity.

Within

the

dynamic

range

of

±100

volt ,

calibra

t

ed

±DC

compari on

voltage

can

be

added

differentially

to

the

input

waveform

to

permit

a

maximum

of

0.005%

or

5

mv

per

mm

to

be

accurately

re olved.

Vertical

Deflection

Factors

0.05

to

25

volt

per

centimeter

in

nine

calibrated

tep ;

al o

continuou ly

variable

(uncalibr

a

ted)

between

tep

and

up

to

60

volt

per

centimeter.

Input

Impedance

1

megohm

±1

%

paralleled

by

24

pf.

Maximum

Allowable

Combined

DC

and

Peak

AC

Input

600

volt ,

ac-coupled.

Maximum

Common-Mode

Signal

±100

volt

at

0.05

volt

per

centimeter.

Higher

voltage

are

permi ible

with

larger

vertical

deflection

factor .

Common-Mode

Rejection

Ratio

40,000

to

1

at

0.05

volt

per

centimeter

with

a

1

-kc

ine

wave,

lower

at

other

en itivitie

and

higher

frequencie .

At

0.05

volt

per

centimeter,

a

200-volt

(p-p)

1

-kc

common



mode

ignal

produce

le

than

1

mm

of

vertical

deflection.

Comparison

Voltages

Available

Three

voltage

range

are

provided:

0

to

±

1

volt,

0

to

±

10

volt ,

and

0

to

±1

00

volt .

An

accurate

10-turn

potentiometer

i

u ed

to

elect

the

compari on

voltage

over

the e

range .

Comparison

Voltage

Regulator

A

regulator

circuit

maintain

compari on

voltage

e



entially

con tant

and

independent

of

normal

power

upply

voltage

upplied

by

the

o cillo cope.

1-1

Specifications

—

Type

Z

Comparison

Voltage

Accuracy

Within

5

millivolt

[0.5%)

on

the

±l-volt

range.

Within

20

millivolt

(0.2%)

on

the

±10-volt

range.

Within

150

millivolt

(0.15%)

on

the

±100-volt

range.

Maximum

Trace

Shift

2

mm

due

to

input

grid

or

ga

current.

Comparison

Voltage

Drift

Le

than

0.1

%

per

100

hour

operation.

Temperature

compen ated

over

normally

expected

tem



perature

range.

Air

filter

in

o cillo cope

hould

be

main



tained

clean,

particularly

when

u ing

the

Z

Unit.

10-Turn

Potentiometer

Linearity

0.05%

Measurement

Resolution

Re olution

accuracy,

at

100-volt

compari on

voltage

—

0.005%

Maximum

re olution

—

5

millivolt

per

millimeter.

Transient

Response

and

Permissible

Signal

Volt



age

Rate

of

Change

Rate

of

ri e

—

1

volt

per

6

n ec,

maximum.

If

thi

rate

i

exceeded,

grid

current

will

flow

in

the

input

tage .

Rate

of

fall

—

1

volt

in

5

n ec,

maximum.

If

thi

rate

i

exceeded,

the

amplifier

will

momentarily

cut

off.

If

over



driven

by

a

ufficiently

fa t

pul e,

the

amplifier

will

“

run

down"

linearly

at

the

above

rate.

Becau e

of

the

wide

dynamic

amplitude

capabilitie

of

the

Z

Unit,

tran ient

re pon e

i

a

function

of

ignal

amplitude.

Mechanical

Specifications

Con truction

—

Aluminum-alloy

cha i .

Front

panel

—

Photo-etched.

Net

weight

—

6

pound .

Accessories

2

—

In truction

Manual

1-2

SECTION

2

OPERATING

INSTRUCTIONS

Front

Panel

A

front-panel

view

of

the

Type

Z

Unit

i

hown

in

Fig.

2-1.

In

addition,

a

brief

functional

de cription

i

given

of

the

front-panel

control ,

input

connector ,

Securing

Rod,

and

Mechanical

Lock,

Connecting

the

Z

Unit

to

the

Oscilloscope

Connect

the

Z

Unit

to

the

a ociated

o cillo cope

by

in erting

the

unit

into

the

plug-in

compartment

and

tighten



ing

the

Securing

Rod.

With

the

Inten ity

control

of

the

o cillo cope

turned

fully

counterclockwi e,

witch

on

the

o cillo cope

power.

Normally

it

i

nece ary

to

wait

a

few

minute

for

the

o cillo cope

and

plug-in

to

warm

up

and

tabilize.

Then

turn

up

the

inten ity

and

et

the

o cillo cope

triggering

control

to

produce

a

free-running

weep.

Po i



tion

the

trace

on

the

creen

u ing

the

POSITION

control

and

the

o cillo cope

beam-po ition

indicator .

Preliminary

Operational

Adjustments

After

the

Z

Unit

ha

warmed

up

and

tabilized,

check

it

operation

to

ee

if

adju tment

of

one

or

more

of

the

following

control

i

nece ary.

Be

ure

that

the

o cillo cope

u ed

in

conjunction

with

the

Z

Unit

i

correctly

calibrated

in

the

vertical-deflection

circuit,

and

that

the

calibrator

output

voltage

i

correct.

1.

Amplifier

DC

alance

If

the

trace

cannot

be

centered

on

the

creen

when

'he

POSITION

control

i

et

near

midrange,

the

AMP

DC

BAL

adju tment

( ee

Fig.

2-2)

mu t

be

checked.

Need

for

thi

adju tment

ari e

mo tly

when

the

Z

Unit

i

tran ferred

from

one

o cillo cope

to

another.

To

make

the

adju tment,

et

the

POSITION

control

to

midrange,

remove

the

left

ide

panel

from

the

o cillo cope,

and

adju t

the

AMP

DC

BAL

control

to

po ition

the

trace

behind

the

horizontal

centerline

of

the

graticule.

2.

Differential

alance

Differential

balance

may

be

quickly

checked

by

applying

100

volt

of

calibrator

ignal

to

both

input

connector .

Set

both

VOLTS/CM

witche

to

.05,

the

AC-DC

witche

to

DC,

and

the

Mode

witch

to

A-B

DIFF.

Ignoring

the

po it

ve

and

negative

pike ,

adju t

the

DIFF.

BAL.

control

to

elimin



ate

any

quare-wave

re pon e

(that

i ,

to

obtain

a

traight-

line

appearance

of

the

trace).

3.

Variable

Attenuator

alance

Any

vertical

hift

of

the

o cillo cope

trace

when

the

VAR.

ATTEN.

control

i

rotated,

with

no

input

ignal

applied,

indicate

need

for

adju tment

of

the

variable

attenuator

balance.

Thi

adju tment

mu t

be

made

in

conjunction

with

the

differential

balance

adju tment

( tep

2)

due

to

interaction

between

the

circuit .

Repeat

the

two

adju t



ment

until

both

are

correct.

Set

the

Mode

witch

to

A

ONLY

and

remove

any

input

ignal .

Adju t

the

VAR.

ATTEN.

BALANCE

control

to

eliminate

any

vertical

hift

of

the

crt

trace

a

the

VAR.

ATTEN.

control

i

rotated.

Check

to

ee

if

the

trace

can

be

centered

a

de cribed

in

tep

1

(Amplifier

DC

Balance).

If

not,

repeat

tep

1.

4.

Gain

The

gain

adju tment

hould

be

checked

periodically

to

a ure

correct

vertical

deflection

factor .

It

hould

al o

be

checked

when

the

Z

Unit

i

tran ferred

from

one

o cillo cope

to

another.

The

adju tment

i

made

u ing

the

calibrator

ignal

from

the

o cillo cope.

Set

the

Mode

witch

to

A

ONLY

and

apply

200

milli



volt

of

calibrator

ignal

to

the

A

input

connector.

Make

ure

the

VAR.

ATTEN.

control

i

et

fully

clockwi e.

Set

the

A

VOLTS/CM

witch

to

.05

and

rotate

the

GAIN

AD



JUST

control

for

exactly

4

centimeter

of

vertical

deflection.

Input

Signal

Connections

It

i

often

po ible

to

make

ignal

connection

to

the

Z

Unit

with

hort-length,

un hielded

te t

lead .

Thi

i

par



ticularly

true

for

high-level,

low-frequency

ignal .

When

uch

te t

lead

are

u ed,

you

mu t

al o

u e

a

ground

con



nection

between

the

o cillo cope

and

the

cha i

of

the

ignal

ource.

(Note:

Exce ively

long

te t

lead

may

cau e

para itic

o cillation .)

In

many

application ,

however,

un hielded

lead

are

un ati factory

for

making

ignal

connection

becau e

of

pickup

re ulting

from

magnetic

field .

In

uch

ca e ,

hielded

cable

hould

be

u ed.

You

mu t

be

ure

that

the

ground

conductor

of

the

cable

are

connected

to

the

cha i

of

both

the

o cillo cope

and

the

ignal

ource.

In

high-frequency

work

it

i

u ually

nece ary

to

terminate

ignal

ource

and

connecting

cable

in

their

characteri tic

2-1

Operating

instructions

—

Type

Z

Polarity

—

Selects

the

compar



ison

voltage

polarity.

VOLTS/CM

—

Selects

the

verti



cal

deflection

factors.

Mode

—

Selects

the

operating

mode

of

the

Z

Unit.

A

INPUT

—

Connector

for

coupl



ing

input

d

c

or

ac

voltages

to

preamplifier.

INPUT

—

Connector

for

coupl



ing

input

de

or

ac

voltages

to

preamplifier.

DIFF.

AL.

—

Adjusts

the

pre



amplifier

for

maximum

dif



ferential

rejection

ratio.

PUSH

TO

DISCONNECT

SIG



NAL

—

Disconnects

signal

from

preamplifier

input.

AC-DC

—

Determines

whether

input

signals

are

d

c

coupled

or

ac

coupled.

VAR.

ATTEN.

—

Varies

the

verti



cal

deflection

factors

between

ranges

of

the

VOLTS/CM

con



trols.

POSITION

—

Se

t

s

the

vertical

position

of

the

trace

on

the

oscilloscope

screen.

Range

—

Selects

the

appropri



ate

comparison

voltage

range.

Securing

Rod

—

Holds

unit

securely

in

the

oscilloscope

plug-in

compartment.

Mechanical

lock

—

Locks

Heli



dial

when

pressed

downward.

Helidial

—

Adjusts

the

com



parison

voltage

over

the

range

selected

by

the

Range

switch.

VAR.

ATTEN.

ALANCE

—

Ad



justed

to

prevent

vertical

trace

shift

as

the

VAR.

ATTEN

con



trol

is

rotated.

AC-DC

—

Determines

whether

input

signals

are

d

c

coupled

or

ac

coupled.

PUSH

TO

DISCONNECT

SIG



NAL

—

Disconnects

signal

from

preamplifier

input.

VOLTS/CM

—

Selects

the

verti



GAIN

ADJUST

—

Sets

the

de-

cal

deflection

factors.

flection

factors

of

the

pre-

amplifier

to

agree

front

panel

markings.

with

the

Fig.

2-1.

Functions

of

front-panel

controls,

input

connectors,

Securing

Rod,

and

Mechanical

Lock.

2-2

http://manoman.sqhill.com

Operating

Instructions

—

Type

Z

Fig.

2-2.

Left

rear

side

view

of

the

Z

Unit

showing

location

of

the

AMP

DC

AL

adjustment.

impedance .

Unterminated

connection

re ult

in

reflection

in

the

cable

and

cau e

di tortion

of

the

di played

wave



form .

When

input

ignal

connection

are

made,

con ider

the

effect

of

loading

upon

the

ignal

ource

due

to

the

input

circuit

of

the

Z

Unit.

The

input

re i tance

of

the

Z

Unit

i

1

megohm

which

i

generally

adequate

to

limit

low-frequency

loading

to

a

negligible

value.

At

high

frequencie ,

however,

the

input

capacitance

of

the

Z

Unit

and

the

di tributed

capacitance

of

cable

become

important.

Capacitive

load



ing

at

high

frequencie

may

be

ufficient

to

adver ely

affect

both

the

di played

waveform

and

the

operation

of

the

ignal

ource.

Both

capacitive

and

re i tive

loading

can

u ually

be

limited

to

negligible

value

through

u e

of

attenuator

probe .

Use

of

Probes

Attenuator

probe

reduce

loading

of

the

ignal

ource.

However,

in

addition

to

providing

i olation

of

the

o cillo



cope

from

the

ignal

ource,

an

attenuator

probe

al o

de



crea e

the

amplitude

of

the

di played

waveform

by

the

attenuation

factor

of

the

probe.

When

making

amplitude

mea urement

with

an

attenuator

probe,

be

ure

to

multi



ply

the

ob erved

amplitude

by

the

attenuation

of

the

probe.

(Additional

information

concerning

probe

attenuation

will

be

found

under

Differential

Preamplifier

Operation

and

At



tenuator

Te t

Point

portion

of

thi

ection

of

the

manual.)

An

adju table

capacitor

in

the

probe

body

compen ate

for

variation

in

input

capacitance

from

one

in trument

to

another.

To

a ure

the

accuracy

of

pul e

and

tran ient

mea



urement ,

thi

adju tment

hould

be

checked

frequently.

To

make

thi

adju tment,

et

the

o cillo cope

calibrator

control

for

a

calibrator

output

ignal

of

uitable

amplitude.

Touch

the

probe

tip

to

the

calibrator-output

connector

and

adju t

the

o cillo cope

control

to

di play

everal

cycle

of

the

waveform.

If

the

probe

cable

i

connected

to

the

A

input

connector

on

the

Z

Unit,

adju t

the

probe

capacitor

for

flat

top

on

the

calibrator

quare

wave.

If

it

i

connected

to

the

B

input

connector,

adju t

for

a

flat

bottom

on

the

quare

wave.

Conventional

Preamplifier

Operation

When

the

Z

Unit

i

u ed

for

conventional

preamplifier

operation,

the

Mode

witch

hould

be

placed

in

either

the

A

ONLY

or

the

—

B

ONLY

po ition.

Input

ignal

hould

then

be

connected

to

the

corre ponding

input

connector.

Operation

of

the

unit

in

the

two

po ition

i

e entially

the

ame

except

that

ignal

applied

to

the

B

input

connector

are

inverted

on

the

di play.

Po itive

voltage

produce

an

upward

deflection

when

applied

to

the

A

input

connector

and

a

downward

deflection

when

applied

to

the

B

input

connector

( ee

Fig.

2-3).

Fig.

2-3.

Waveforms

applied

to

the

A

Input

connector

produce

an

upright

display,

while

waveforms

applied

to

the

Input

are

in



verted.

The

amount

of

vertical

deflection

produced

by

a

ignal

i

determined

by

the

etting

of

the

VAR.

ATTEN.

control

and

the

VOLTS/CM

witch.

Calibrated

deflection

factor

indicated

by

the

etting

of

the

VOLTS/CM

witch

apply

only

when

the

VAR.

ATTEN.

control

i

et

fully

clockwi e.

Seriou

error

in

di play

mea urement

may

re ult

if

the

etting

of

thi

control

i

inadvertently

moved

away

from

the

fully

clockwi e

po ition.

The

range

of

the

VAR.

ATTEN.

control

i

approximately

2.5

to

1

to

provide

continuou ly

variable

(uncalibrated)

vertical-deflection

factor

between

calibrated

etting

of

the

VOLTS/CM

witche .

Voltage

mea urement

may

be

made

directly

from

the

o cillo cope

creen

by

noting

the

deflection

factor

on

the

appropriate

VOLTS/CM

witch

dial,

and

the

amount

of

deflection

on

the

creen.

Then

multiply

the

deflection

on

the

creen

by

the

etting

of

the

VOLTS/CM

witch

and

the

attenuation

factor.

If

any,

of

the

probe.

Placing

the

AC-DC

witch

in

the

AC

po ition

in ert

a

d

c

blocking

capacitor

in

erie

with

the

input

circuit.

In

the

AC

po ition,

the

input

time

con tant

i

0.1

econd

and

the

low-frequency

re pon e

i

—

3

db

at

2

cp .

Thu

ome

attenuation

exi t

even

at

60

cp .

Becau e

the

input

d

c

ignal

may

be

uppre ed

by

mean

of

the

calibrated

com



pari on

voltage

feature,

there

are

few

occa ion

where

the

ac-coupling

mode

will

be

needed.

Two

principle

occa ion

are:

(1)

When

it

i

de ired

to

get

a

quick

look

at

the

ac

component

of

a

ignal

which

ha

a

large

d

c

component

and

(2)

where

there

i

a

difference

in

d

c

level

of

the

two

ignal

to

be

ob erved

during

differential

mode

of

operation.

The

tolerance

of

the

input

circuit

time

con tant

(at

—

3

db

frequency)

are

nominally

±2%.

When

tighter

2-3

http://manoman.sqhill.com

Operating

Instructions

—

Type

Z

matching

between

A

and

B

input

circuit

i

nece ary,

one

input

d

c

blocking

capacitor

may

be

“

padded"

with

a

mall

additional

capacitance,

generally

le

than

0.001

/ifd.

The

PUSH

TO

DISCONNECT

SIGNAL

button

allow

the

ignal

to

be

momentarily

removed

from

the

input

without

the

bother

of

di connecting

the

probe

or

coaxial

input

con



nector.

Thi

provide

an

ea y

method

for

finding

the

ba e



line

of

zero

voltage

level

on

the

crt.

(When

utmo t

ac



curacy

in

mea urement

i

required,

trace

deviation

from

exact

zero

due

to

ga

or

grid

current

mu t

be

con idered.)

The

POSITION

control

may

then

be

adju ted

to

make

the

zero

level

lie

at

any

graticule

mark

de ired.

Differential

Preamplifier

Operation

The

primary

purpo e

of

differential

operation

i

to

elim



inate

unde irable

common-mode

ignal .

The

term

“

common



mode

ignal"

i

defined

a

that

ignal

which

i

common

to

both

input

of

a

differential

amplifier.

It

mo t

commonly,

but

not

nece arily,

repre ent

unwanted

hum

or

noi e.

Thi

feature

can

be

u ed,

for

example,

to

ob erve

the

ignal

acro

one

circuit

element

while

effectively

eliminat



ing

the

remainder

of

the

circuit

from

the

ob ervation .

T

h

i

i

accompli hed

by

connecting

the

ignal

at

one

end

of

the

element

to

one

input

of

the

Z

Unit

and

the

ignal

at

the

other

end

of

the

element

to

the

other

input

of

the

unit

Differential

operation

between

the

two

input

i

obtained

when

the

Mode

witch

i

in

the

A-B

DIFF.

po ition.

Maximum

common-mode

rejection

i

obtained

when

both

input

at



tenuator

are

et

to

XI.

Common-mode

rejection

i

a

func



tion

of

frequency

in

practical

amplifier .

It

i

40,000

to

1

for

de

common-mode

ignal

in

the

Z

Unit

and

remain

near

that

value

through

audio

frequencie ,

decrea ing

a

the

frequency

increa e .

The

differential

or

common-mode

rejection

ratio

of

the

Z

Unit

de cribe

the

ability

of

the

unit

to

reject

common



mode

ignal .

Common-mode

rejection

ratio

i

be t

defined

a

the

ratio

of

amplifier

re pon e

to

that

part

of

the

input

ignal

not

common

to

both,

with

re pect

to

the

re pon e

of

the

amplifier

to

any

input

ignal

which

i

common

to

both

input .

It

i

defined

numerically

in

the

following

ex



ample.

If

an

input

ignal

con i t

of

100

volt

(p-p)

of

60-cp

hum

and

0.1

volt

of

de ired

ignal,

the

100-volt

hum

would

cau e

,

—

1

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

time

100

volt

or

2000

cm

of

deflection,

and

.

05

volt /cm

the

ignal

would

cau e

an

additional

2

cm

of

deflection.

If

conventional

preamplifier

operation

were

u ed,

the

de



ired

ignal

would

be

deflected

off

the

creen

and

could

not

be

ob erved.

However,

if

differential

operation

i

u ed

and

common-mode

rejection

were

2000

to

2

or

1000

to

1,

then

the

hum

and

de ired

ignal

would

each

produce

2

cm

of

deflection.

The

re ulting

combined

wave



(c)

100-volt

60

~

hum

only.

Control

s

etting

s si

mil

a

r

0.05

v/cm.

Mode:

A-

DIFF.,

dc-coupled.

Sweep

Rato:

to

(a)

except

Mode

is

—

ONLY.

0.5

mill

se

c/cm.

Fig.

2-4.

Common-mode

rejection

by

the

Z

Unit.

2-4