Tektronix 47E5A, DM44 Instruction Manual

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. Tektronix, Inc.

P.O.

Box

500

Beaverton, Oregon

97077

070·2163

·00

TEKTRONIX®

47E5A

DSCILLDSCDPE

AND

DM44

DIGITAL

MULTIMETEA

PEA

INSTRUCTION

MANUAL

Serial Number

___

Fi

rst Printing AUG. 1976

WARRANTY

All

TEKTRONIX

instruments

are

warranted

against

defective

materials

and

workmanship

for

one

year.

Any

questions

with

respect

to

the

warranty

should

be

taken

up

with

your

TEKTRONIX

Field

Engineer

or

representative.

All

requests

for

repairs

and

replacement

parts

should

be

directed

to

the

TEKTRONIX

Field

Office

or

representative

in

your

area.

This

will

assure

you

the

fastest

possible

service. Please

include

the

instrument

Type

Number

or

Part

Number

and

Serial

Number

with

all

requests

for

parts

or

service.

Specifications

and

price

change

privileges

reserved.

Copyright

© 1976

by

Tektronix,

Inc.,

Beaverton,

Oregon.

Printed

in

the

United

States

of

America.

All

rights

reserved.

Contents

of

this

publication

may

not

be

reproduced

in

any

form

without

permission

of

Tektronix,

Inc.

U.S.A.

and

foreign

Tektronix

products

covered

by

U.S.

and

foreign

patents

and/or

patents

pending.

TEKTRONIX

is a

registered

trademark

of

Tektronix,

Inc.

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TABLE OF

CONTENTS

Page

LIST

OF

ILLUSTRATIONS

iv

BASIC

OSCILLOSCOPE

DISPLAYS

LIST

OF

TABLES

v

NORMAL

SWEEP

DISPLAY

MAGNIFIED

SWEEP

DISPLAY

BEFORE

OPERATING

1

DELAYED

SWEEP

DISPLAY

INTRODUCTION

MIXED

SWEEP

DISPLAY

SAFETY

INFORMATION

1

X-Y

DISPLAY

OPERATING

VOLTAGE

1

SINGLE

SWEEP

DISPLAY

Line

Voltage

Selection

2

Regulating

Range

Selection

2

DM44

DISPLAYS

AND

MEASUREMENTS

OPTIONS

3

RESISTANCE

CONTROLS,CONNECTORS,AND

VOLTS

INDICATORS

4

TEMPERATURE

VERTICAL

4

Accuracy

Check

DISPLAY

7

TIME

AND

1/TIME

DM44

7

TRIGGER

8

HORIZONTAL,

CALIBRATOR,

AND

POWER

12

APPLICATIONS

AND

MEASUREMENTS

REAR

PANEL

14

PRELIMINARY

LEFT SIDE

PANEL

14

Signal

Ground

RIGHT

SIDE

PANEL

14

Input

Coupling

Capacitor

Precharging

@

475A/DM44

Operators

Page

16

16
17

17

18
18
19

20

20
22

24
24
27

28

28
28
28

TABLE OF

CONTENTS

(cont)

APPLICATIONS

AND

MEASUREMENTS

(cont)

Page

APPLICATIONS

AND

MEASUREMENTS

(cont)

Page

OPERATOR'S ADJUSTMENTS

AND

CHECKS

29

PHASE DIFFERENCE MEASUREMENTS

42

Trace Rotation

29

HIGH

RESOLUTION PHASE DIFFERENCE

Probe Compensation

29

MEASUREMENTS

43

Vertical Gain Check

30

PULSE JITTER MEASUREMENTS

44

Basic 475A

Timing

Check

30

DELAYED OR MIXED SWEEP

DM44

Timing

Check

30

MAGNIFICATION

45

External Horizontal Gain Check

31

Magnified Sweep Starts

After

Delay

45

PEAK-TO-PEAK VOLTAGE

Triggered

Delay Sweep

Magnification

46

MEASUREMENTS-AC

31

INSTANTANEOUS

VOLTAGE

BASIC

475A DELAYED OR

MIXED

SWEEP

TIME

MEASUREMENTS-DC

32

ALGEBRAIC

ADDITION

34

MEASUREMENTS

48

COMMON MODE REJECTION

35

TIME

DIFFERENCE BETWEEN REPETITIVE

AMPLITUDE

COMPARISON

PULSES (BASIC

475A) 48

MEASUREMENTS

36

TIME DURATION MEASUREMENTS

TIME-DURATION

MEASUREMENTS

37

(BASIC 475A) 49

FREQUENCY

MEASUREMENTS

38

FREQUENCY MEASUREMENTS (BASIC 475A)

50

RISETIME MEASUREMENTS

39

TIME

DIFFERENCE BETWEEN TWO PULSES

TIME DIFFERENCE

BETWEEN TWO

. FROM DIFFERENT SOURCES (BASIC

475A)

51

PULSES FROM DIFFERENT SOURCES

40

RISETIME (BASIC

475A)

52

TIME COMPARISON MEASUREMENTS

41

MIX (BASIC 475A)

53

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TABLE OF

CONTENTS

(cont)

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DM44

DELAYED

OR

MIXED

SWEEP

TIME

Page

OPERATOR

'S

SPECIFICATIONS

(cont)

Page

MEASUREMENTS

54

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TIME

DIFFERENCE

BETWEEN REPETITIVE Z

AXIS

INPUT

65

PULSES

(DM44)

56

OUTPUTS

65

TIME

DURATION

MEASUREMENTS

(DM44)

57

AC

POWER

SOURCE

65

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FREQUENCY

MEASUREMENTS

(DM44) 58

ENVIRONMENTAL

65

TIME

DIFFERENCE

BETWEEN

TWO

PULSES

DM44

DIGITAL

MULTIMETER

66

FROM

DIFFERENT

SOURCES

(DM44)

58

RESISTANCE

66

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RISETIME

(DM44)

60

TIME

66

MIX

(DM44)

61

1/TIME

66

TEMPERATURE

66

OPERATOR'S

SPECIFICATIONS

62

DC

VOLTAGE

66

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475A

OSCILLOSCOPE

62

VERTICAL

62

TRIGGERING

63

ACCESSORIES

68

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DIFFERENTIAL

TIME

MEASUREMENT

STANDARD

ACCESSORIES

68

(BASIC

475A)

63

OPTIONAL

ACCESSORIES

68

DIFFERENTIAL

TIME

MEASUREMENT

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(DM44)

64

HORIZONTAL

64

OPTIONS

69

X-Y

64

OPTION

4

69

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CALIBRATOR

64

OPTION

7

69

@

475A/DM44

Operators

ill

LIST OF

ILLUSTRATIONS

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Page

Page

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Fig.

1.

Regulating

range

selector

and

line

Fig. 17.

Common-mode

rejection.

36

fuse.

3

Fig. 18.

Time

duration.

38

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Fig. 2.

Vertical

controls,

connectors,

and

Fig. 19. Risetime.

39

indicators.

4

Fig.

20.

Time

difference

between

two

pulses

Fig.

3.

Display

and DM44

controls,

from

different

sources. 40

connectors,

and

indicators.

6

Fig. 21.

Phase

difference.

43

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Fig.

4.

Trigger

controls,

connectors,

and

Fig. 22.

High-resolution

phase

difference.

43

indicators

.

8

Fig. 23.

Pulse jitter.

44

Fig . 5.

Trigger

controls, connectors,

and

Fig.

24.

Delayed sweep

magnification.

46

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indicators.

10

Fig. 25.

Time

difference

between repetitive

Fig.

6.

Horizontal,

calibrator,

and

power

pulses. 49

controls,

connectors

, and

indicators.

12

Fig. 26.

Time

duration.

50

Fig.

7.

Rear panel and left side panel

controls,

Fig. 27.

Time

difference

between

two

pulses

I

connectors,

and

indicators.

15

from

different

sources.

51

Fig.

8.

Resistance.

21

Fig. 28. Risetime .

53

Fig.9.

Volts.

23

Fig. 29.

Time

difference

between repetitive

I

Fig. 10.

Temperature.

25

pulses.

56

Fig. 11.

Probe

compensation

.

29

Fig. 30.

Time

duration

and

frequency

Fig. 12.

Basic

475A

timing

check

.

30

measurements

.

57

Fig. 13.

DM44

timing

check

.

31

Fig. 31.

Time

difference

between

two

pulses

I

Fig.

14.

Peak-to-peak voltage

of

a waveform.

32

from

different

sources.

59

Fig. 15.

Instantaneous

voltage

measurements.

33

Fig. 32. Risetime.

60

Fig.

16.

Algebraic

addition.

35

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475A/DM44

Operators

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LIST OF TABLES

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Page

Page

TABLE 1 Regulating

Ranges

2

TABLE 4 Centigrade

to Fahrenheit

Conversion

26

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TABLE

2 Resistance Ranges

20

TABLE

5 DM44 Delayed Sweep

Displays

54

TABLE

3 Volts Ranges

22

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@

475A/DM44

Operators

v

475A

Oscilloscope

with

DM44

Digital

Multimeter.

475A1DM44 Operators

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BEFORE

OPERATING

INTRODUCTION

The

Tektronix

475A

Oscilloscope

is a dual-channel

portable

instrument.

The

dual-channel

dc-to-250

MHz

vertical

system

provides

calibrated

deflection

factors

from

5

millivolts

to

10

volts/division. The

sweep

trigger

circuits

are

capable

of

stable

triggering

over the full

bandwidth

capabilities

of

the

vertical

deflection

system .

The

horizon-

tal

deflection

system

provides

calibrated

sweep rates

from

0.5

second

to 0.

01

microsecond/division

along

with

delayed sweep features

for

accurate

relative-time

measurements. A

X10

magnifier

extends

the

calibrated

sweep

rate

to 1 nanosecond/division. The

instrument

operates

over a wide

variation

of

line

voltages and

frequencies. Maximum

power

consumption

is

about

100

watts

.

The

Tektronix

DM44

Digital

Multimeter

measures 0

ohm

to

20

megohms, 0 dc

volt

to 1200

dc

volts

(+

or

-),

or

(using

the

temperature

probe)

- 55°C to

+150°C. The

measurement

is

displayed

on

a 3-1/2

digital

display

while

the

oscilloscope

operates

normally

.

The

digital

multimeter

and

oscilloscope

combine

to

provide a digital

readout

of

the

time

between

any

two

points

on the

oscilloscope

display.

Both

time

measure-

ment

points

are

displayed

on the

crt

at the same

time. The

1/

TIME

function

can

provide

direct

measurement

of

frequency.

SAFETY

INFORMATION

The

instrument

is

designed

to operate from a

single-

phase

power

source

with

one

of

the

current-carrying

conductors

(the

Neutral

Conductor)

at

ground

(earth)

potential.

Operation

from

power

sources

where

both

current-carrying

conductors

are live

with

respect to

ground

(such as phase-to-phase on a three-wi

re

system)

is

not

recommended, since

only

the Line

Conductor

has

over-current

(fuse)

protection

within

the

instrument.

The

instrument

has a

three-wire

power

cord

with

a

three-terminal

polarized

plug

for

connection

to

the

power

source

and safety-earth.

The

ground

(earth) terminal

of

the

plug

is

directly

connected

to

the

instrument

frame.

For

electric-shock

protection,

insert

this

plug

only

in a mating

outlet

with

a safety-earth

contact.

@

475A/OM44

Operators 1

OPERATING VOLTAGE

~

This

instrument

may

be

damaged

if

operated

with

the line voltage

selector

switch

or the

regulating

range

selector

set

for

the

wrong

applied

line voltage

or

if

the

wrong

line fuse is

used

.

Line Voltage Selection

This

instrument

operates from

either

a 115-volt

or

a

230-

volt

nominal

line

voltage

source, 48 to 440 hertz.

To

convert

from

one

nominal

line

voltage

range to the other,

move the Line

Voltage

Selector

switch

(located

on

side

panel) to

indicate

the

correct

nominal

voltage. A 115-to-

230

volt

adapter

may be required

for

the

line-cord

plug

. Be

sure to use the

correct

line fuse for the line

voltage

selected (see

Table 1).

Regulating Range Selection

The

Regulating Range

Selector

assembly (located on

the rear

panel) is set

for

one

of

the line voltage ranges

shown

in Table 1. It also

contains

the

line fuse

for

overload

protection.

To

change

the

regulating

range:

1.

Disconnect

the

instrument

from the

power

source

.

2. Loosen the

two

captive screws

that

hold

the cover

on the

selector assembly; then

pull

to

remove the

cover

.

3.

Pullout

the range

selector

switch

bar (see Fig. 1).

Select a range from Table 1

which

is

centered

about

the

average

line voltage . Slide the bar to the desired

position

and

plug

it in. Push the

cover

on and

tighten

the

screws

.

TABLE

1

Regulating Ranges

Regulating Range

Range

Selector

115-Volts. 230-Volts

Switch Position

Nominal Nominal

LO

(Switch bar

in

lower

holes)

99 to

121

volts

198

to

242 volts

M (Switch bar

in

middle

holes) 104

to

126

volts

207

to

253

volts

HI (Switch

bar

in

upper

holes)

108

to

132 volts 216

to

264 volts

Fuse Size

1.5 A

3AG

0.75 A

3AG

Fast-blow Fast-blow

2

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LINE

FUSE

1739·1

Fig. 1. Regulating range selector and line fuse.

OPTIONS

Options

are available to

alter

oscilloscope

performance

to

meet

particular

applications. A number

in

either

MOD

slot

(see Item 53,

Controls,

Connectors,

and

Indicators)

indicates a modified

oscilloscope.

475A/OM44

Operators

3

4

CONTROLS,

CONNECTORS

AND

INDICATORS

Fig.

2.

Vertical

controls,

connectors,

and

indicators.

VERTICAL

1.

CH 1 and

CH 2 VOL

TS/DIV-Selects

the

vertical

deflection

factor

in a 1-2-5

sequence

(VAR

control

must

be

in the

calibrated

detent

for

the

indicated

deflection

factor).

2.

VOL

TS/DIV

Readout-Consists

of

two

small

lamps

for

each

channel, located

beneath

the

skirt

of

each

VOL TS/OIV

knob. One

or

the

other

lamp

will

light

up

to

indicate

the

correct

deflection

factor

when a probe

with

a

scale -

switching

connector

is used. A

probe

without

this

connector

lights

the

X1

lamp.

3.

VAR-Provides

continuously

variable

uncalibrated

deflection

factors between the

calibrated

settings

of

the

VOL

TS/ OIV

switch,

and

extends

the

maximum

vertical

deflection

to at least 25 volts

per

division

(10 volt

position).

4.

UNCAL

Lamp-Indicates

when

the

VAR

VOL TS/ OIV

control

is

out

of

the

calibrated

detent

and the

vertical

deflection

factor

is

uncalibrated

.

475A/DM44

Operators

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5.

POSITION-Positions

the

display

vertically

. In the

X-V

mode,

the

CH 1 POSITION

control

positions

on

the X

axis

(horizontally)

and

the

CH 2 POSITION

control

positions

on

the Y-axis

(vertically).

6.

CH

1 OR X

and

CH

2 OR

V-Input

connectors

for

application

of

external

signals

to

the

inputs

of

the

vertical

amplifier.

In the X-V

mode

of

operation,

the

signal

connected

to

the

CH 1 OR X

connector

provides

horizon-

tal

deflection

and

the

signal

connected

to

the

CH

2 OR Y

connector

provides

vertical

deflection.

7.

AC-GND-DC-Selects

the

method

used to

couplea

signal

to the

input

of

the

vertical

amplifier

. In

the

AC

position, signals

are

capacitively

coupled

to

the

vertical

amplifier. The

dc

component

of

the

input

signal

is

blocked

.

In

the

GND

position,

the

input

of

the

vertical

amplifier

is

disconnected

from

the

input

connector

and

grounded

to

allow

the

input

coupling

capacitor

to

precharge.

In

the

DC

position,

all

components

of

the

input

signal are passed to

the

input

amplifier.

8.

VERT

MODE-Selects

mode

of

operation

for

ver-

tical

amplifier

system

.

CH

1:

Channell

only

is di

splayed.

AL

T: Provides

dual-trace

display

of

the

signals

of

both

channels. Display

is

switched

between

channels

at

the

end

of

each sweep.

Useful

at sweep rates faster than

about

50

microseconds/division

.

ADD: Signals

applied

to the

CH 1 and

CH 2 input

connectors

are

algebraically

added, and

the

algebraic

sum

is

displayed

on

the crt.

The

INVERT

switch

in

Channel

2

allows

the

display

to be

CH 1 plus

CH 2 or

CH 1

minus

CH

2.

Useful

for

common-mode

rejection

to

remove

an

undesi

red

signal

or

for

dc

offset.

CHOP

: Provides

dual-trace

display

of

the

signals

of

both

channels. Display

is

switched

between

channe

ls at a

repetition

rate

of

approximately

250 kHz .

Useful

at

sweep

rates

slower

than

about

50

microseconds/division, or

when a dual-trace, single-sweep

display

is

required

.

CH

2:

Channel 2 only

is

displayed.

It

must

be selected

in X-

Y

operation

.

9.

100 OR 20

MHz

BW/TRIG

VIEW-

Three-purpose

switch

that

limits

the

bandwidth

of

the

vertical

amplifier

system

to

approximately

100

MHz

(first

detent)

or20

MHz

(second

detent)

when

pulled, or

when

pressed, causes the

signal

applied

to

A Tr

igger

Generator

to

be

displayed

on

the crt.

10.

INVERT-Channel

2

display

is inverted in the

INVERT

(button

in)

position.

@

475A/DM44

Operators

5

Fig.

3.

Display and DM44 controls, connectors, and

indicators.

6

475A/DM44 Operators

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DISPLAY

11.

Internal

Graticule-Eliminates

parallax. Risetime.

amplitude

and

measurement

pOints are

indicated

at the

left-hand

graticule

edge.

c,

12.

BEAM

FINDER-Compresses

the

display

to

within

the

graticule

area

independently

of

display

position

or

applied

signals

and

provides a visible

viewing

level.

13.

INTENSITY-Controls

brightness

of

the

crt

dis-

play.

14.

FOCUS-Adjusts

for

optimum

display

definition

.

15.

SCALE

ILLUM-Controls

graticule

illumination.

16.

ASTIG-Used

in

conjunction

with

the

FOCUS

control

to

obtain a well-defined

display

. It

does

not

require

readjustment

in

normal

use.

17.

TRACE

ROTATION-Adjusts

trace

to

align

with

the

horizontal

graticule

lines.

DM44

18.

Input

Connectors-Two

banana

jacks

provide

+

(red)

and

COM

(black)

inputs

for

voltage

and

resistance

only.

19.

Probe

Connector-Input

connector

for

the

temperature

probe

.

20.

Readout-Negative

polarity

indication

is

automatic

for

negative

dc

voltage

and

temperature

with

no

polarity

indication

for

positive

measurement. A blinking

display

indicates

overrange.

The

decimal

point

is

position-

ed

by

the

FUNCTION

and

RANGE

controls

for

multimeter

operation

and

by

the

oscilloscope A TIME/DIV

switch

in

the

TIME

or

1/TIME

modes.

21.

RANGE-Selects

from

.2 V to

1.2 kV

dc

in 5 ranges

(1200

volts

is the

maximum

safe

input

in the 1.2 kV

dc

mode);

from 200

ohms

to

20

megohms

in 6 ranges.

22.

FUNCTION-Selects

VOL

TS.

OHMS. TEMP

(QC).

1ITIME.

or

TIME

functions

of

the DM44.

23.

Scale

Factor

Lamps-Two

lamps.

In the

TIME

function

. the

Readout

and Scale

Factor

Lamps

indicate

the

time

difference

between the

two

intensified

zones on the

crt

display. One

lamp

or

the

other

will

light

to

indicate

ms

or

f..lS

.

No

lamp

lit indicates

seconds.

In the

1/TIME

function

the

Readout

and Scale

Factor

Lamps

indicate

the

number

of

measured

intervals per

unit

of

time.

One

lamp

or

the

other

will

light

to

indicate

intervals

per

ms

(1/ms

lamp)

or

intervals

per

f..lS

(1/f..ls

lamp).

No

@

475A/DM44

Operators

7

8

Fig.

4.

Trigger

controls,

connectors,

and

indicators.

lamp

lit

indicates

intervals

per

second

. If

the

duration

of

one

event

is

being

measured, the

Readout

and Scale

Factor

Lamps

indicate

frequen

cy.

The

1/

ms

lamp

in-

dicates

kHz, the

1//.1s

lamp

indicates

MHz, and

no

lamp

lit

indicates

Hz.

24.

/.:.;.

TIME-Used

in

conjunction

with

the

DELAY

TIME

POSITION

control

in the

TIME

and

1/TIME

func-

tions. The

/.:.;.

TIME

control

moves

only

the

time-

measurement

point.

The

DELAY

TIME

POSITION

control

moves

both

the

reference

point

and

the

time-

measurement

point.

With

the

time-measurement

point

to

the

left

of

the

reference

point

the

Readout

indicates

a

negative

time

difference

.

NOTE

You

can

modify

your

instrument

to

make

the OELA Y

TIME

POSITION

control

move

only

the

reference

pOint . The

procedure for

making

this

modification

is

located

in the

Maintenance

section

of

the OM44

Service

manual

.

TRIGGER

25.

TRIG

MODE-Determines

the

mode

of

trigger

operation

for

A Sweep

AUTO:

Sweep

is

initiated

by

the

applied

triggersignal.

In the

absence

of

an

adequate

trigger

signal, or

if the

trigger

repetition

rate is less than

about

20

hertz

, the

sweep

free

runs

and

provides a bright

reference

trace

.

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NORM:

Sweep

is

initiated

by

the

applied

trigger

signal.

In

the

absence

of

an

adequate

trigger

signal

, there is

no

trace. When

the

trigger

rate is

too

low

for

AUTO

use

NORM

.

SINGL

SWP : When

this

pushbutton

is

pushed

, the A

Sweep

operates

in the

single

sweep mode.

After a single

sweep

is

displayed,

further

sweeps

cannot

be

presented

until

the

SINGLE

SWP

button

is

again

pushed. It is

useful

when

the

signal

to

be

displayed

is

not

repetitive

or

varies in

amplitude, shape

or

time

causing

an

unstable

conven-

tional

display

. It

can

also

be used

to

photograph

a

nonrepetitive

signal.

26. READY

Lamp-Indicates A Sweep

is

"armed"

and,

upon

receipt

of

an

adequate

trigger

signal,

will

present a

single-sweep

display

.

27.

TRIG

Lamp-Indicates

that A Sweep

is

triggered

and

will

produce a stable

display.

It is

useful

for

setting

up

the

trigger

circuits

when a trigger

signal

is available

without a display

on

the

crt

(for

example,

when

using

ex terna I

triggers).

28. A

TRIG

HOLDOFF-Provides

continuous

control

of

time

between

sweeps.

Allows

triggering

on

aperiodic

signals

(such as

complex

digital

words)

. In the

fully

clockwise

position

(8

ENDS A), A

sweep

is reset at the end

of 8 sweep

to

provide

the fastest

possible

sweep

repetition

rate

for

delayed-sweep

presentations

and

low-repetition

rate signals. Use the A

trigger

controls

for

the best

possible

display

before

using

the A

TRIG

HOLDOFF

control.

29.

COUPLING-Determines

method

used to

couple

signals

to

the

trigger

generator

circuit.

AC: Signals

are

capacitively

coupled

to

the

input

of

the

trigger

generator.

Dc

is

rejected and Signals

below

about

60

Hz

are

attenuated

.

LF REJ:

Signals

are

capacitively

coupled

to

the

input

of

the

trigger

circuit.

Dc

is rejected and

signals

below

about

50 kHz are

attenuated

. It is useful

for

providing

a

stable

display

of

the

high-frequency

components

of

a

complex

waveform

.

HF REJ:

Signals

are

capacitively

coupled

to

the

input

of

the

trigger

circuit. Dc

is rejected and

signals

below

about

60 Hz and above

about

50 kHz are attenuated. It is

useful

for

providing

a stable

display

of

the

low-frequency

components

of a complex

waveform.

DC

: All

components

of a trigger

signal are

coupled

to

the

input

of

the

trigger

circuit.

It is useful

for

providing

a

stable

display

of

low-frequency

or

low-repetition

rate

signals,

except

the

combination

of

the

AL

T (dual trace)

mode

with

the

trigger

SOURCE

switch

in

NORM

.

@

475A/DM44

Operators

9

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Fig. 5. Trigger controls, connectors, and indicators.

30.

SLOPE-Selects

the slope

of

the

trigger

signal

that

I

starts the sweep.

I

+: Sweep can be

triggered

from the

positive-going

I

portion

of a trigger

signal.

-:

Sweep can be

triggered

from the

negative-going

portion

of a trigger

signal.

Correct

SLOPE

setting

is

important

in

obtaining

a

display

when

only a portion

of a cycle

is being

displayed.

31. LEVEL - Selects the

amplitude

point

on the

trigger

signal at

which

the sweep

is

triggered.

It

is

usually

adjusted

for the desired

display

after

trigger

SOURCE,

COUPLING

and SLOPE have been selected.

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32.

SOURCE-Determines

the

source

of

the

trigger

signal

coupled

to

the

input

of

the

trigger

circuit.

NORM:

Trigger

source

is

displayed

signal(s).

It does

not

indicate

time

relationship

between

CH

1 and

CH

2

signals.

However,

stable

triggering

of

non-time-related

signals

usually

can be

obtained

by

setting

VERT

MODE

to

AL

T,

SOURCE

to

NORM

and

COUPLING

to

LF REJ.

Carefully

adjust

LEVEL

for a stable

display.

CH

1: A sample

of

the

signal

available

in

Channel

1 is

used as a

trigger

signal.

CH 2 signal

is

unstable

if it is

not

time-related.

CH

2: A sample

of

the

signal

available

in

Channel 2 is

used as a

trigger

signal.

CH 1 signal

is

unstable

if it is

not

time-related.

LINE

(A

Trigger

circuit

only): A sample

of

the

power-

line

frequency

is used as a

trigger

signal.

It is useful

when

the

input

signal

is

time-related

(mu Itiple

or

submultiple)

to

the

line

frequency

or

when

it is

desirable

to

provide

a

stable

display

of a line-frequency

component

in a

complex

waveform.

EXT:

Signals

connected

to

the

External

Trigger

Input

connectors

are used

for

triggering.

External

signals

must

be

time-related

to

the

displayed

signal

for a stable

display.

It is usefu I

when

the

internal

signal

is

too

small

or

contains

undesired

signals

that

could

cause

unstable

triggering.

It

is

useful

when

operating

in

CHOP

mode.

EXT

-:-

10

(A

Trigger

circuit

only):

External

trigger

signal

is

attenuated

by a factor

of

10.

STARTS

AFTER

DELAY

(8

Trigger

circuit

only):

8

Sweep

runs

immediately

after

the

delay

time

selected

by

the

DELAY-TIME

POSITION

control.

When

making

differential

time

measurements

you

must

use

this

mode

to

obtain

valid

measurements.

On

instruments

equipped

with

a DM44

you

must

use

this

mode

to

obtain

valid

measurements

when

using

the

TIME

or 1 ITIME

functions.

33. External Trigger

Inputs-Input

connectors

for

ex-

ternal

trigger

signals.

@

475A/DM44 Operators

11

Fig.

6.

Horizontal,

calibrator,

and

power

controls,

connectors,

and

indicators.

HORIZONTAL,

CALIBRATOR,

AND

POWER

34a. A

AND B TIME/DIV

AND

DELAY

TIME-A

TIME/DIV

switch

(clear plastic skirt) selects the sweep

rate

of

the A Sweep

circuit

for

A sweep

only

operation

and

selects the basic delay time (to be used

by

the

DELAY-

TIME

POSITION

control)

for

delayed sweep

operation.

B

TIME/DIV

switch

(pullout

and rotate to

unlock)

selects the

sweep rate

for

the B Sweep

circuit

for delayed

sweep

operation

only

. A VAR

control

must be in the

calibrated

detent

for

calibrated

A Sweep rates. When

both

TIME

/DIV

switches are

fully

counterclockwise

to the X-V

position

,

the

horizontal

(X-axis)

display

is the

CH

1 input.

34b.

DM44 A AND B TIME/DIV

AND

DELAY

TIME-

The

controls

operate

in the same

manner

as 37a above.

The A TIME

/DIV

switch

also

controls

the

TIME

lamps and

decimal

point

location

when

the DM44 is in the

TIME

or 1/TIME

MODE

.

35.

FINE/POSITION-Positions

the

display

horizontal-

ly

for

A sweep and B Sweep .

36. X10

MAG-Increases

displayed

sweep rate

by

a

factor

of

10. It extends fastest sweep rate to 1

nanosecond/division.

The

magnified

sweep is the

center

division

of

the

unmagnified

display

(0.5

division

either

side

of

the

center

graticule

line).

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37.

VAR-Provides

continuously

variable sweep rates

between

the

calibrated

settings

of

the A

TIME/DIVswitch.

It

extends

the

slowest A Sweep

rate

to

at least 1.25

seconds/division.

The A Sweep

rate is

calibrated

when

the

control

is set

fully

clockwise

to

the

calibrated

detent.

Must

be in the

detent

position

to

make

accu rate

differential

time

measurements.

On

instruments

equipped

with

a DM44

the

VAR

control

must

be in

the

detent

position

to

make

accurate

measurements

in the

TIME

and 1/

TIME

func-

tions

.

38.

UNCAL

Lamp-Indicates

the A

Sweep

rate is

uncalibrated

(VAR

control

out

of

the

calibrated

detent)

.

39.

X10

MAG

Lamp-Indicates

that the X10

magnifier

is on.

40a.

DELAY

TIME

POSITION-Provides

variable

sweep

delay

to

more

than

10

times

the

delay

time

indicated

by

the A

TIME/DIV

switch.

40b.

DM44

DELAY

TIME

POSITION-Operates

in the

same

manner

as

41a. Also,

when

the DM44 is in the

TIME

or

1/TIME

function,

this

control

operates

in

conjunction

with

the!::.

TIME

control.

The

DELAY

TIME

POSITION

control

moves

both

the reference

point

and

the

time-

measurement

pOint. The!::.

TIME

control

moves

only

the

time-measurement

point.

With

the

time-measurement

point

to the

left

of

the

reference

point

the

Readout

indicates a negative time

difference

.

NOTE

You can

modify

your

instrument

to

make

the OELA Y

TIME

POSITION

control

move

only

the reference

point.

The

procedure

for

making

this

modification

is

located

in the

Operating

Information

section

of

the

OM44 Service

manual

.

41..

CALIBRATOR-A

combination

current

loop/square-wave

voltage

output

that

permits

the

operator

to

compensate

voltage

probes

and

check

vertical

gain,

current

probes

and

oscilloscope

operation.

It is

not

intended

to verify time-base

calibration

.

42.

POWER-Turns

instrument

power

on and

off

.

43.

LOW

LINE

Lamp-Indicates

that the

applied

line

voltage

is

below

the

lower

limit

of

the

regulating

range

selected

by

the

Regulating

Range Selector.

44.

HORIZ

DISPLAY-Determines

the

mode

of

opera-

tion

for

the

horizontal

deflection

system .

A:

Horizontal

deflection provided

by A Sweep

at a

sweep

rate

determined

by

the

setting

of

the A

TIME

/DIV

switch.

B sweep is

inoperative

.

@

475A1DM44

Operators

13

MIX:

The

first

part

of

the

horizontal

sweep is displayed

at a rate set

by

the

A TIME/ DIV

switch

and

the

latter

part

of

the sweep at a rate set by the B

TIME/DIV

switch

. Relative

amounts

of

the

display

allocated

to

each

of

the

two

sweep

rates are

determined

by

the

setting

of

the

DELAY-TIME

POSITION

control.

A INTEN:

The

sweep rate

is

determined

by the A

TIME/DIV

switch.

An

intensified

portion

appears

on

the

display

during

the B Sweep time,

which

is

about

10 times

the B

TIMEIDIV

switch

setting. This

switch

position

provides a check

of

the

duration

and

position

of

the B

Sweep (delayed sweep)

with

respect

to

the A Sweep

(delaying

sweep).

B

DL

YO:

The

sweep rate is

determined

by

the B

TIME/DIV

switch

with

the delay

time

determined

by

the

selling

of

the

DELAY

TIME

(A

TIME/DIV)

switch

and the

DELAY-TIME

POSITION

control.

REAR PANEL

45. A

+GATE-Provides a positive-going

rectangular

pulse

coincident

with

the A Sweep time,

which

can be

used to

trigger

the

signal

source

(with

TRIG

MODE

switch

set

to

AUTO).

46. B

+GATE-Provides a positive-going

rectangular

pulse

coincident

with

the B Sweep time,

which

can be

used to

trigger

the signal

source

after

a selected

delay

time,

providing

that A Sweep

is

triggered

internally.

47.

CH

2 VERT

SIGNAL

OUT-Provides a sample

of

the

signal

applied

to

the

CH 2 input

connector

.

48. EXT

Z-AXIS-Permits

intenSity

modulation

of

the

crt

display.

Does

not

affect

display

waveshape. Signals

with

fast rise

and

fall

provide

the

most

abrupt

intensity

change. Signals

must

be

time-related

to

the

display

for

a

stable display. Useful

for

adding

time

markers

in

un-

calibrated

modes

of

operation.

49.

Line

Fuse

Holder-Contains

the

line

fuse and the

regulating

range selector. See

Table 1 for

change

informa-

tion.

50.

Regulating

Range

Selector-Shown

in

Medium

regulating

range. See

Table 1 for

change

information

.

51. PROBE

POWER-Power

source

for

active

probe

systems .

52.

Line

Cord-Makes

the

connection

between the

oscilloscope

and the

power

source. The

cord

may

be

conveniently

stored

by

wrapping

it

around

the

feet on the

rear

panel.

53.

MOD

SLOTS-A

number

in

either

slot

indicates

the

instrument

contains

an

option

or

other

modifications.

LEFT SIDE PANEL

Access

for

externally

available

adjustments

(see Fig. 7).

RIGHT

SIDE PANEL

LINE

VOLTAGE

SELECTOR

SWITCH

(located

on the

right

side)-Selects

either

115 V

or

230 V

nominal

line

voltage.

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CH 1 GAIN

10mV

Fig.

7.

Rear panel and

left

side

panel

controls,

connectors, and

indicators

.

475A/OM44

Operators

(2039)

2163-01

15

BASIC OSCILLOSCOPE DISPLAYS

These

instructions

permit

the

operator

to

obtain

the

most

commonly

used basic

displays.

NORMAL

SWEEP DISPLAY

1.

Set the

controls

as

follows:

VERT

MODE

VOL

TS/DIV

VOLTS/DIV

VAR
AC-GND-DC
Vertical

POSITION

100

MHz-20

MHz

BW

INVERT

Vertical

CH 1
Position

determined

by

amplitude

of

signal to

be

applied

Calibrated

detent
AC
Midrange
Not

limited

(yellow

band

not

visible)

Button

out

Horizontal

TIME/DIV

Switches

Locked

together

at 1 ms

A

TIME/DIV

VAR

Calibrated

detent

HORIZ

DISPLAY

A

X10

MAG

POSITION

Off

(button

out)

Midrange

Display

INTENSITY

Fully

counterclockwise

Trigger

(Both A and B

If applicable)

SLOPE

LEVEL

SOURCE

COUPLING

TRIG

MODE

(A

only)

A TRIG

HOLDOFF

+

o

NORM
AC
AUTO
NORM

2.

Pull the POWER

switch

(on).

Connect

the

signal

to

the

CH 1 input

connector

.

3.

Adjust

the

INTENSITY

control

for

the

desired

display

brightness.

If the

display

is

not

visible

with

the

INTENSITY

control

at

midrange,

press the

BEAM

FINDER

pushbutton

and

adjust

the CH 1

VOL

TS/DIV

switch

to

reduce

the vertical

display

size.

Center

the

compressed

display

with

the

vertical

and

horizontal

POSITION

con-

trols; release

the

BEAM

FINDER

pushbutton.

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4. Set the

CH 1 VOL

TS/DIV

switch

and

vertical

POSITION

control

to

locate

the

display

within

the

display

area.

5.

Adjust

the A

Trigger

LEVEL

control

for a stable

display

.

6. Set

the A TIME/DIV

switch

and

the

horizontal

POSITION

control

to

locate

the

display

within

the

display

area.

Then

adjust

the

FOCUS

control

as needed.

MAGNIFIED

SWEEP DISPLAY

1.

Obtain a Normal

Sweep

Display.

2.

Adjust

the

horizontal

POSITION

control

to move the

area to

be

magnified

to

with

in the

center

graticule

division

(0.5

division

on

each

side

of

the

center

vertical

graticule

line).

It

may

be

necessary

to

change

the

TIME/DIV

switch

setting

.

3.

Push the X 10

MAG

switch

(on) and

adjust

the

horizontal

POSITION

control

for

precise

positioning

of

the

magnified

display. Divide

the

TIME/DIV

setting

by

10

to

determine

the

magnified

sweep rate.

DELAYED SWEEP DISPLAY

NOTE

Differential

time

measurements

and

measurements

using

the TIME

or 1 ITIME

functions

of

the

DM44

are

invalid

when

the B

Trigger

SOURCE

switch

is

not

set

to

STARTS

AFTER

DELA Y.

1.

Obtain a Normal

Sweep

Display

.

2.

Set the

HORIZ

DISPLAY

switch

to A

INTEN

and the

B

Trigger

SOURCE

switch

to

STARTS

AFTER DELAY.

3.

Pullout

on

the B

TIME/DIV

knob

and

turn

cw

until

the

intensified

zone

is the desired

length. Adjust

the

INTENSITY

control

as needed

to

make

the

intensified

zone

distinguishable

from

the rest

of

the

display. If

your

instrument

is

equipped

with a DM44

, set the

FUNCTION

switch

to a function

other

than

TIME

or

1/TIME

for a single

delayed sweep . Dual delayed

displays

are discussed in

step 6.

@

475A/DM44

Operators 17

4.

Adjust

the

DELAY

TIME

POSITION

control

to move

the intensified zone to

cover

the

portion

of

the

display

to

be displayed in delayed form.

5.

Set the HOR IZ

DISPLAY

switch

to

B DL Y'D.

The

intensified zone

noted

in steps 3 and 4 is

now

displayed in

delayed form.

The

delayed sweep rate

is

indicated

by the

dot

on

the B TIME/DIV

knob.

6.

If

your

instrument

is

equipped

with

a DM44 delayed

displays

of

two

signals can be

obtained

at the same

time

.

The

DM44

will

indicate

the

time

difference

between the

beginning

of

the delayed

displays. To

obtain

two

delayed

displays

set the

FUNCTION

switch

to

TIME

and

the

VERT

MODE

switch

to ALT.

The

DELAY

TIME

POSITION

control

positions

both

delayed displays.

The

AL

T DELAY

control

positions

only

the

CH

2 delayed display.

7.

For

a delayed

display

with

less jitter, set the B

Trigger

SOURCE

switch

to

the

same

position

as the A

Trigger

SOURCE

switch

and adjust

the

B LEVEL

control

for

a stable display.

MIXED SWEEP DISPLAY

1.

Obtain a

normal

sweep display.

2.

Pullout

on the B

TIME/DIV

knob

and

turn

cw

to the

desired sweep rate.

If

your

instrument

is

equipped

with

a

DM44 set the

FUNCTION

switch

to a

function

other

than

TIME

or

11TIME

for

a single mixed display. Dual

mixed

displays are discussed in step

4.

3.

Set the

HORIZ

DISPLAY

switch

to MIX.

The

display

now

contains

two

sweep rates.

The

first

portion

of

the

display

is

at the A sweep rate

while

the

latter

portion

of

the

display

is at the B sweep rate.

The

start

of

the B sweep rate

portion

can be changed

by

adjusting

the

DELAY

TIME

POSITION

control.

4.

If

your

instrument

is

equipped

with

a DM44, mixed

sweep displays

of

two

signals can be

obtained

at the same

time. The

DM44

will

indicate the time

difference

between

the

beginning

of

the

B sweep

portions

of

the

two

displays.

To

obtain

two

mixed

sweep

displays

set the

FUNCTION

switch

to

TIME

and the VERT

MODE

switch

to

ALT.

The

DELAY

TIME

POSITION

control

positions

both

mixed

displays.

The

6.

TIME

control

positions

only

the

CH 2

mixed

display

.

X-Y DISPLAY

1.

Preset the

instrument

controls

as given in step 1

of

Normal

Sweep Display, then

turn

the

instrument

power

on.

Allow

several minutes

for

instrument

warm-up.

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2.

Set the

T/ME/D/V

switches

to

X-Y and the VERT

MODE

switch

to CH

2.

Apply

the vertical signal to the

CH 2

OR Y

input

connector

and the horizontal signal

to

the CH 1 OR X

input

connector

.

3.

Advance the INTENSITY

control

until

the display is

visible.

If the

display

is

not visible

with

the

INTENSITY

control

at midrange, press the BEAM FINDER

pushbutton

and

adjust

the

CH

1 and

CH

2 VOL

TS/D/V

switches

until

the

display

is

reduced in size, both

vertically

and

horizon-

tally.

Center

the

compressed

display

with

the POSITION

controls

(CH 2

POSITION

vertically, CH 1 POSITION

horizontally);

release the BEAM FINDER

pushbutton.

Adjust

the FOCUS

control

for a

well-defined

display.

SINGLE SWEEP DISPLAY

1. Obtain a Normal Sweep Display. For random

Signals, set the

trigger

circuit

to

trigger

on a signal that

is

approximately

the same

amplitude

and frequency

as

the

random

signal.

2.

Push the

SINGL

SWP

button

on the A

TRIG

MOOE

switch. The next

trigger

pulse starts the sweep and

displays a

single trace. If no

triggers

are present, the

READY

lamp lights,

indicating

the A Sweep

Generator

circuit

is set and

waiting

to be triggered.

3.

After

the sweep is complete, the

circuit

is

"locked

out"

and the READY lamp is out. Press the

SINGL

SWP

button

to prepare the

circuit

for

another

single-sweep

display.

@

475A/OM44

Operators

19

DM44 DISPLAYS

AND

MEASUREMENTS I

Except

for

the

TIME

and 11TIME

functions,

the DM44 is

independently

usable

anytime

the

oscilloscope

is

turned

on.

The

TIME

and

1/TIME

functions

are discussed in the

Oscilloscope

Applications

and Measurements

section

of

this

manual

I

under

Delayed

or

Mixed

Sweep Measurements.

RESISTANCE

The

meter

may

be

damaged

by

attempting

to

measure voltage

if

the

meter

is in the resistance

mode

of

operation

(OHMS

FUNCTION

button

push-

ed

in)

and

the

applied

voltage is in excess

of

120 V

rms.

1. Push

in

the

OHMS

FUNCTION

button

and the

20 MO RANGE

button.

See Fig.

8.

2.

Connect

the

+ and

COM

leads to the

unknown

resistance.

3.

Reduce the range, using the

following

table,

until

a

proper

readout

is

obtained

.

TABLE 2

Resistance Ranges

RANGE

READOUT

MEASUREMENT

20

MO

20 .

00-02

.00

20

MO-2

MO

2

MO

2.

000-0

.200

2

MO-200

kO

200 kO 200 .

0-20.00

200

kO-20

kO

20 kO

20 .

00-02.00

20

kO-2

kO

2

kO

2.000-0.200

2

kO-200

0

2000

200.

0-000.0

2000-00

A

blinking

readout on any range,

when

connected

to

any

unknown

resistance ,

indicates

an overrange

condi-

tion

and a need

to

select a

higher

range.

A

blinking

readout , when

meterleadsaredisconnected

is normal.

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RANGE

SELECTION

Fig. 8. Resistance .

475A/DM44

Operators

(465/DM

-O-

2)2039

-9

21

VOLTS

The

maximum

safe

input

voltage

is

±1200 V (dc

+

peak

ac)

between

the +

and

COM

inputs

or

between

the +

input ,and

chassis

.

The

maximum

COM

floating

voltage

is

±500 V (dc

+

peak

ac)

to

chassis

.

The

meter

may

be

damaged

by

attempting

to

measure

voltage

if

the

meter

is

in

the

resistance

mode

of

operation

and

the

applied

voltage is in

excess

of

120 V rms.

If

the

reading

exceeds

1200

Vor

the

readout

blinks

(indicating

overrange)

disconnect

the +

lead

at

once

to

prevent

possible

meter

damage.

1.

Push in the

VOLTS

FUNCTION

button

and the

1.2 kV RANGE

button.

See Fig.

9.

2.

Connect

the

COMMON

lead to the reference

point

(usually a ground

or

test

point)

and the

HIGH

lead to the

unknown

voltage

to be measured and observe the reading .

3.

Reduce the range,

using

Table

3,

until a proper

readout is

obtained

.

NOTE

When

no

voltage

is

applied

in

the

20

V

to

1.2

kV

ranges, the

readout

is

0000

and

individual

readout

elements

may

blink. Also,

noise

picked

up

by

the

meter

leads

may

increase

the

readout

in

the.2

Vand

2 V ranges .

A

blinking

readout

on

any

range

indicates

an

overrange

condition

and a need

to

select a higher

range .

TABLE 3

Volts Ranges

RANGE

READOUT

MEASUREMENT

1.2

kV

1 .

200-0.200

1.2

kV-200

V

200 V 200.

0-020.0

200

V-20

V

20 V

20.

000-02

.00 20

V-2

V

2V

2.000-0

.200 2

V-.2

V

200 mV 0.

200-0.000

.2

V-O

V

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Fig. 9. Volts.

475A/DM44

Operators

(465/DM

-O-

3)2039-10

23

TEMPERATURE

The

maximum

safe voltage

on

the

measurement

surface

is

±400 V (dc + peak

ac)

above chassis

ground

.

The

sensor

tip

is

fragile

and

may

break

if

dropped

or

subiected

to excessive stress. Force

exerted

on

the

sensor

tip

should

not

exceed

20

pounds

.

"the

reading

exceeds

- 55° C

or

+ 150°

C,

remove

the

probe

at

once

to

prevent

probe

damage .

1.

Push in the TEMP (0

C)

FUNCTION

button

. See

Fig. 10.

2.

Apply

the

temperature

probe

to

the device to be

measured so the flat surface

of

the

probe

tip

mates against

the device to be measured and observe the reading.

See

Table 4 to

convert

the reading from

centigrate

to

fahrenheit.

NOTE

Temperature

accuracy

is

affected

by

several

factors

such

as the

angle

of

contact

between

the

probe

and

the

device

to

be

measured, a

thermal

gradient,

heat

removed

from the

device

by

the

probe,

etc.

These items

and

other

probe

information

are in the

probe

manual,

which

should

be reviewed.

Accuracy Check

The

DM44

is

calibrated

to

its

original

probe,

giving

accurate readings

within

2°C

for

examples that

follow

.

The DM44

should

be recalibrated to any

replacement

probe

.

In the

following

checks

, use an accurate

thermometer

to

verify

water

temperature.

Anything

in

solution

affects

the

melting

temperature and the

boiling

point

is affected

by changes

in

altitude

and

barometric

pressure .

low

Temperature

Allow a container

(preferably

insulated)

of

crushed

ice

to melt

until

there are

only

a few pieces

of

ice

remaining.

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PROBE

INPUT

GREASE

YSILICONE

OBE

APPiHE

SURFACE

TpOSSIBLEI.

TO

RED

(WHEN

MEASU

----

-

--------------:.;n

·0

Temperature.

Fig. 1 .

D

M44

Operators

475AI

PROBE

TEMPERATURE

SENSOR

TIP

(465

THIS

NOT

<J

IO

M·O·4)2039·11

25

CENTIGRADE

FAHRENHEIT

CENTIGRADE

FAHRENHEIT

CENTIGRADE

FAHRENHEIT

CENTIGRADE

FAHRENHEIT

26

TABLE

4

CENTIGRADE

TO

FAHRENHEIT

CONVERSION

-

50

-

40

-

30

-

20

-10

0

II

I

I I I I

I'

,

I'

" " " "

I,

, , ,

I'

, , ,

I,

I , I

I'

I I I

II

, I I

1\

I'

I I

i I

iii

I'

lit

iii iii

iii

i i

III

iii

I i

11111

iii

i I

'I

iii

(

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'I

i

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I ii' (

iii

i

111

iii

i ill i

-

50

-40

-30 -20

-10

0

10

20

30

o

10

20

30

40

50

II

' I ' , ' , , ,

I'

, , , I , , , ,

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, ,

~

I ' , I I I , , , , I I , I I I' , I , I I I ' , I

i

IIIII

iill·il.

lidt·r"I")""'I""

iiiliiiq'iiiliillili'llii

'fifilii!

i

1111

40

50

.

60

70

80

90

100

110

120

50

60

70

80

90

100

I I , , I I' I I I

I'

, , , I ' I I I

I,

I I I I , , , ,

I,

~

I , I I I , I

~

, I I I I I I I I I

"111111

ililftl

illfrlii

1'lii.fiiP"!

iliiliilr.

iii

ii.iii'lliff

liliql!

i

ilill'

130

140

150

160 170

180 190

200

210

100

110

120

130

140

150

I ' , I I

~

I , I I

I'

, , I I ' , , , I

I'

'I I I I , I , ' 1 I I I ' I I I

II

I I I , I \ ' , I

1IIIIni

flljiIJlfilljlfl

I""plllllllllll"lli

11111111111111111"11111 I 1 "II

220

230

240

250

260

270

280

290

300

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Operators

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To

prevent

possible

probe

damage, be sure

only

the

sealed

portion

of

the

probe

is

immersed

(see Fig. 10).

Put the

probe

tip

into

the water,

avoiding

the

side

or

bottom

of

the

container

. Wait

for

the readout to stabilize,

indicating

the

probe

has reached the

water

temperature.

The

readout

should

be

-2°C

to

2°C.

There

should

be

ice

remaining

after

the test to

verify

that

inserting

the

probe

did

not

raise the

water

temperature

.

High Temperature

Bring

water

to a

slow

boil

(to prevent

splattering).

Put

the

probe

tip

into

the water,

avoiding

the

side

or

bottom

of

the container. Wait

for

the readout to stabilize,

indicating

the

probe

has reached the

water

temperature.

The

readout

should

be between 98°C and 102°C

for

clean

water

at sea level.

TIME

AND

1/TIME

See DM44

DELAYED

OR

MIXED

SWEEP

TIME

MEASUREMENTS

in this manual.

@

475A/OM44

Operators

27

APPLICATIONS AND MEASUREMENTS

Refer to Basic

Oscilloscope

Displays as needed to

obtain

correct

displays.

PRELIMINARY

Signal Ground

~

Avoid

cross-grounding

because

instrument

damage

may

occur

.

The

most reliable measurements are made when the

oscilloscope

ground

is

connected

to

the

ground

of

the

unit

under

test by

the

ground

strap on

the

signal probe.

Also

a

ground

lead can be

connected

to the

ground

banana

jack

on

the

oscilloscope

chassis to establish a

common

ground

with

the

unit

under

test.

Input Coupling Capacitor Precharging

In the

GND

position, the

input

signal is

connected

to

ground

through a one-megohm

resistor to form a

precharging

network. This

network

allows the

Input

Coupling

capacitor

to

charge

to the average

dc

voltage

level

of

the

signal

applied

to the probe.

Thus, any

large

voltage transients

accidentally

generated

will

not

be

applied to the

amplifier

input.

The

precharge

network

also

provides a measure

of

protection

to

the

external ci rcu

itry

by

reducing

the

current

levels that can be

drawn

from the

external

circuitry

during

capacitor

charging.

The

following

procedure

should

be used whenever

the

probe

tip

is

connected

to a signal sou rce having a

different

dc

level than

that

previously

applied,

especially if the

dc

level

difference

is

more than 10 times the

VOL

TS/ DIV

setting.

1. Before

connecting

the

probe

tip to a signal source,

set the

Input

Coupling

switch to

GND.

2.

Touch

the

probe

tip

to

oscilloscope

chassis

ground

.

Wait several

seconds

for

the

Input

Coupling

capacitor

to

discharge.

3.

Connect

the

probe tip to the signal

source

.

4.

Wait several

seconds

for

the

Input

Coupling

capacitor

to charge.

5.

Set the

Input

Coupling

Switch

to AC. The

display

will

remain on the screen so

the

ac

component

of

the

signal can

be

measured in the

normal

manner.

28

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OPERATOR'S

ADJUSTMENTS

AND

CHECKS

To

verify

measurement

accuracy, perform

the

follow-

ing

checks

and

adjustments

before

making a measure-

ment

. See the

Calibration

section

of

the Service

manual

for

calibration

information

.

Trace Rotation Adjustment

Normally

not

required. Obtain a Normal

Sweep

Display

using

only

steps 1

through

3. Set the

CH 1 input

Coupling

switch

to

GND

to

display a free-running

trace

with

no

vertical

deflection. Adjust

the

TRACE

ROTATION

(screw-

driver

adjustment

located

below

the

crt

graticule)

to

align

the trace

with

the

center

horizontal

graticule

line

.

Probe Compensation

Miscompensation

is

one

of

the greatest

sources

of

operator

error.

Most

attenuator

probes

are

equipped

with

adjustments

to

ensure

optimum

measurement

accuracy

.

Probe

compensation

is

accomplished

as

follows

:

Obtain a Normal

Sweep

Display

presentation

of

the

calibrator

square-wave voltage. Set the

appropriate

VOL

TS/DIV

switch

to.1 V position

and

the

Input

coupling

to

DC.

Check

the

waveform

presen

tation

for

overshoot

or

rolloff,

and

if

necessary, readjust

compensation

for

flat

tops

on the

waveforms

. See Fig. 11.

Refer

to

probe

manual

for

method

of

compensating

the

probe

being used.

-

t-

J.

.,,;

-

I-

-

1

00

f-

"-

f-

I-

I-

-

lO

I

1

r

I-

I-

'-

-

+-

.-

r-=

~

.

...

I-

-r-

1-

-

l-

"-

I-

.~

'-

...

"-

f-

-

-~

,-

f-

r

I-

Er

~

Ir

~

..

r.

f-

~'"'

I'-~

'-

f-

Fig. 11.

Probe

compensation

.

CORRECT

FLAT

OVER

COM·

PENSATED

(OVERSHOOT)

UNDER

COM·

PENSATED

(ROLLOFF)

465/DM·Q

·5

@

475A/DM44

Operators

29

Vertical Gain Check

Obtain a Normal

Sweep

Display

presentation

of

the

cal

ibrator

square-wave voltage. Set the

appropriate

VOL

TS/DIV

switch

to the 50 mV

position

and the

Input

Coupling

switch

to DC. Make sure the VAR

VOL

TS/DIV

control

is in the

calibrated

detent.

Check

that the vertical

deflection

is 5.8

to

6.2

divisions.

Basic 475A Timing Check (60 Hertz Line Only)

Obtain a Normal

Display. Set the A

TIME/DIV

switch

to

5 ms

position

. Set the A

Trigger

SOURCE

switch

to

LINE

.

Push the

TRIG

VIEW

switch

and

hold

it in.

This

displays

a

sample

of

the line voltage. Use the A

Trigger

LEVEL

control

to

vertically

position

the

top

of

the

display

to

with

in

the

display

area. Use the

horizontal

position

control

to

position

the

left

peak to the left g raticule

edge

(see Fig.

12).

Verify

the

horizontal

distance

between the first and

the

fourth

peaks is 9.8

to

10.2 divisions. If the

fourth

peak

is

not

visible,

verify

the

horizontal

distance

between the

first

and

the

third

peaks is 6.53

to

6.79 divisions.

DM44 Timing Check (60 Hertz Line Only)

Perform

the

Basic

475A

Timing

Check

to

verify

the

accuracy

of

the

horizontal

deflection

system.

Leave

controls

set as

for

the

Basic

475A

Timing

Check

except

as

follows:

B

TIME/DIV

HORIZ

DISPLAY

B

SOURCE

FUNCTION

t::"

TIME

I

I

51-1s
A

INTEN

STARTS

AFTER

DELAY
TIME
To

move

the

time-

measurement

pOint

to

the

right

of

the

reference

point.

9.8 TO

10.2

6.53

TO

6.79

100

.

. . . . . . .

..

. . . .

..

9[\

n.

\

1

\

10

I

I

...

. . . . .

..

.

. . . .

1738,14

Fig. 12.

Basic

475A

timing

check

.

30

475A/OM44 Operators

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Push the

TRIG

VIEW

button

and

hold

it in. Use the

DELAY

TIME

POSITION

control

to

move the reference

point

to

the

center

horizontal

graticule

line

(see Fig. 13,

Point

A). Use the

AL T DELAY

control

to

move the

time-

measurement

point

to the

center

horizontal

graticule

line

on

the

next

cycle

(see Fig. 13,

Point

B).

Verify

the

readout

is 16.49 to 16.84

and

the ms lamp is lit.

·

·CR·

;..

...

..

~

. .

r\

\

100

\

\

1

1\

,

1O

I

I"

. .

.. . , .

...

..

. . .

..

1738·15

Fig.

13.

DM44 timing check.

External Horizontal Gain Check

(If

X-Y

operation

is to be used .)

Use

steps 1

through 3 of

the Basic

Oscilloscope

Displays

procedure

for

obtaining

a

Normal

Sweep

Display

of

the

calibrator

square-wave

voltage

waveform ; then, set the

TIMEIDIV

switch

to

X-Yo

With the

calibrator

signal

connected

to

the

CH

1 OR X

input

connector

and the

CH 1 VOL

TS/DIV

switch

set to

50

mV , the

crt

display

should

be

two

dots

separated

horizontally

by 5.75

to 6.25

divisions

.

PEAK-TO-PEAK VOLTAGE

MEASUREMENTS-AC

Obtain a Normal

Display. Make sure the VAR

VOL

TS/DIV

control

is in the

calibrated

detent.

Vertically

position

the

display

so the

lower

portion

coincides

with

a

horizontal

graticule

line (see Fig. 14,

Point A).

Horizontally

position

the

display

so

one

of

the

upper

peaks

coincides

with

the

center

vertical

graticule

line

(see Fig. 14, Point B).

Measure the

vertical

deflection

from

peak-to-peak

(Point

A to

Point

B).

@

475A/DM44

Operators

31

32

POSITION

TO

CENTERLINE

VERTICAL

DEFLECTION

~c...,lI-+-t------t--r--t--#-t----I-~

~

___

i

MEASURE

AMPLITUDE

FROM

ATO

B

(1738·16)2039·15

Fig. 14. Peak-to-peak voltage

of

a waveform.

NOTE

If

the

amplitude

measurement

is

critical

or

if

the

trace is

thick

as a

result

of

hum

and/or

noise

on

the

signal

, a

more

accurate

measurement

can be

ob-

tained

by

measuring

from

the top

of a peak

to the

top

of

a valley. This

will

subtract

the trace thickness from

the

measurement

.

Multiply

the vertical

deflection

just

measured

by

the

VOL

TS/DIV

switch

setting .

Also

include

the

attenuation

factor

of

the

probe

if the

probe

does

-not

have a scale-

factor

switching

connector.

Example:

The

peak-to-peak

vertical

deflection

measured

is

4.6

divisions

(see Fig . 14)

with

a VOL

TS/DIV

switch

setting

of

.5.

Using the

formula

:

Volts

Peak-to-peak

vertical

deflection

(divisions)

Substituting

the given values:

X VOL

TS/DIV

setting

Volts Peak-to-Peak = 4.6 X 0.5 V = 2.3 volts.

INSTANTANEOUS VOLTAGE

MEASUREMENTS-DC

Obtain a Normal

Display

. Make sure the VAR

VOL

TS/DIV

control

is

in the

calibrated

detent.

475A/DM44 Operators

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To

determine

the

polarity

of

the voltage to be

measured, set the

input

coupling

switch

to

GND

and

vertically

position

the baseline to the

center

of

the crt. Set

the

input

coupling

switch

to

DC.

If

the

waveform

moves

to

above

the

center

of

the

crt,

the

voltage

is positive. If

the

waveform

moves

to

below

the

center

of

the

crt,

the

voltage

is'

negative.

Set

the

input

coupling

switch

to

GND

and

position

the

baseline

to a convenient

reference

line. For

example, if

the

voltage

to

be

measured

is positive, then

position

the

baseline to the

bottom

graticule

line

.

Switch

the

Input

Coupling

Switch

to

DC. Measure the

divisions

of

vertical

deflection

between the reference line

and

the desired

point

on

the

waveform

(see Fig. 15).

Multiply

the

veritcal

deflection

by

the

VOL

TS/DIV

switch

setting.

Include

the

attenuation

factor

of

the

probe

if

the

probe

does

not

have a

scale-factor

switching

connector

.

EXAMPLE:

The

vertical

distance

measured is

4.6

divisions

(see Fig. 15), the

waveform

is above the

reference

line, and the

VOL

TS/DIV

switch

is

set

to 2.

_ L

:EGATIVE

REFERENCE

LINE

~

I

,J

·

dx

90

u

""

--

--

-

T---

~

VERTICAL

DEFLECTION

MEASURE

L_

AMPLITUDE

1 "

ATO

B

____

t .

OR

NEGATIVE

AMPLITUDE

CTfB

W

465/DM·

O-7

Fig_

15.

Instantaneous

yoltage

measurement.

Using

the

formula

:

Instan­taneous
Voltage

vertical VOL

TSI

distance

X

polarity

X DIV

(divisions)

setting

Substituting:

= 4.6 X

(+1)

X 2 V = 9.2 volts.

@

475A/DM44 Operators

33

If a negative

voltage

is to be measured,

position

the

trace to the

top

graticule

line

and measure from C to 8 (see

Fig. 15).

The

ground

reference

line

can be

checked

at

any

time

by

switching

to the

GND

position.

This

method

can also be used to measure

one

voltage

with

respect to

another. Position

one

of

the

voltage

levels

to a

convenient

reference line. Measure the

divisions

of

vertical

deflection

between the reference line and the

other

voltage

level.

Substitute

this value in the

formula

just

given.

ALGEBRAIC

ADDITION

In the

ADD

position

of

the VERT

MODE

switch,

the

waveform

displayed

is the

algebraic

sum

of

the

signals

applied

to the

CH

1 and

CH 2 inputs

(CH 1 +

CH

2). If the

CH 21NVERT

switch

is pushed, the

waveform

displayed

is

the

difference

of

the

signals

applied

to the CH 1 and

CH

2

inputs(CH

1 -

CH

2).

The

total

deflection

factor

in the

ADD

mode

is

equal

to the

deflection

factor

indicated

by

either

VOL

TS/DIV

switch

(when

both

VOL

TSIDIV

switches

are set to the same

position).

The

following

general

precautions

should

be observed

when

using

the

ADD

mode.

1.

Do

not exceed the

input

voltage

rating

of

the

oscilloscope.

2.

Do

not

apply

signals

that

exceed

an

equivalent

of

about

eight

times the

VOL

TSIDIV

switch

settings. For

example,

with a VOL

TS/DIV

switch

setting

of

0.5, the

voltage

applied

to that

channel

should

not

exceed

about

four

volts

. Large voltages may

distort

the

display.

A

common

use

of

the

ADD

mode

is to

provide a dc

offset

for a signal

riding

on a dc

level.

EXAMPLE:

The

Channel 1 signal

is on a 3

division,

positive

dc

level (using the

center

line

as

zero volts). See

Fig. 16A.

Multiply 3 divisions

by

the

VOL

TS/DIV

switch

setting

to

determine

the

dc-level

value.

Apply

a negative

dc

level

(or

a positive level

using

the

CH

21NVERT

switch),

of

the value

determined,

to

Channel 2 input.

See Fig . 168.

The

ADD

mode

puts the

resultant

display

within

the

operating

range

of

the

POSITION

controls

.

34

475A/DM44 Operators

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ov

VI

V

II

II

V

~

'"

'0

I

0

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POSITIVE

LEVEL

(A)

CHANNEL 1 SIGNAL
WITH 3 DIVISIONS

OF

POSITIVE

DC

LEVEL.

.J

~

ov

"

NEGATIVE

OFFSET

(8)

CHANNEL 2 DISPLAY
WITH 3 DIVISIONS

OF

NEGATIVE

OFFSET

.

Fig

. 16.

Algebraic

addition.

"'

V I V

V

/ /

..

(C)

RESULTANT

DISPLAY

465/0M·O·19

COMMON-MODE

REJECTION

EXAMPLE:

The

signal

applied

to the

CH 1 input

contains

unwanted

lin e

frequency

components

(see Fig.

17A).

To

remove

the

undesired

components

use the

following

procedure

.

The

ADD

mode

can

be used to

display

signals

that

contain

undesirable

components. These

undesirable

components

can be e

liminated

through

common

mode

rejection.

The

precautions

given

under

algebraic

addition

should

be

observed

.

1.

Connect

a line fr

eque

ncy

signal

to the

CH 2 input.

2. Set the VERT

MODE

switch

to

AL

T and the

CH

2

INVERT

switch

to

on

(button in).

Adjust

the CH 2

@

475A1DM44 Operators

35

CH 1

SIGNAL

J

.:"

WITH

UNWANTED

LINE

FREQUENCY

100

COMPONENT

90

CH 2

SIGNAL

FROM

LINE

FREQUENCY

SOURCE

(INVERTED)

....

10/

r

j

1'

....

./

--

--

,"

.......

",,"

.......

......

"-

(A)

CH 1

AND

CH 2 SIGNALS.

.-

SIGNAL

WITH

~-

-...

..

..

"':'

"..-

-

..

'

...

,

,

./

V

-r-

- -

LI

~~~~6~~

~

~

C Y

~+t++++j-t+<*ft-+++t++>+t>+++-t++++tH+<>tH++t++++i

CANCELED

OUT

r-

- -

------

--

--

----

'~--+--+--~~--~~---r~r--r~

L

(6)

RESULTANT

SIGNAL.

1738·19

Fig. 17.

Common-mode

reJection.

VOL

TS/DIV

and VAR VOL

TS/DIV

controls

so

the

CH

2

display

is

about

the same

amplitude

as

the undesired

portion

of

the CH 1

display

(see Fig. 17A).

3. Set the VERT

MODE

switch

to

ADD.

Slightly

readjust the CH 2 VAR VOL

TS/DIV

control

for

maximum

cancellation

of

the undesired signal

component

(see Fig.

178).

AMPLITUDE

COMPARISON

MEASUREMENTS

If

comparisons

of

an

unknown

signal

with

a reference

signal are

repetitious

(e.g., on an assembly

line

test) it

is

possible to

obtain

more

accurate

easily read

measurements if the VAR

VOL

TS/DIV

control

is

adjusted

to

set the reference signal to an

exact

number

of

divisions.

The

unknown

signal can then be

quickly

and easily

compared

with

or

adjusted to an exact

number

of

divisions.

Other

unknown

signals

may

be measured

without

disturbing

the setting

of

the VAR VOL

TS/DIV

control

by

establishing a vertical

conversion

factor

and an

arbitrary

deflection

factor.

The

amplitude

of

the reference signal

must be

known

before a

vertical

conversion

factor

can be

established.

36

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Determine

the

vertical

conversion

factor

using

this

formula

:

Vertical

reference

signal

amplitude

(volt)

Conversion

Factor

vertical

VOLTS/DIV

deflection

X

switch

(divisions)

setting

Determine

the

arbitrary

deflection

factor

using

the

formula

:

Arbitrary

Vertical

VOLTS/DIV

Deflection

Conversion

X

switch

Factor

Factor

setting

To

measure

the

amplitude

of

an

unknown

signal.

set the

VOL TS/

DIV

switch

to a setting

that

provides

sufficient

vertical

deflection

to

make an

accurate

measurement. Do

not

readjust

the VAR

VOL

TS/DIV

control.

Measure

the

vertical

deflection

in

divisions

and

calculate

the

amplitude

of

the

unknown

signal

using

the

following

formula:

Signal

Amplitude

Arbitrary

deflection

factor

or

Vertical

X

deflection
(divisions)

Signal

Vertical

VOL

TS/DIV

Vertical

=

Convers

ion X

Amplitude

Factor

switch

X

deflection

setting

(divisions)

EXAMPLE: The

reference signal

amplitude

measured is

30 volts

with a VOL

TS/DIV

switch

setting

of

5 and

the

VAR

VOL

TS/

DIV

control

adjusted

to

provide

a vertical

deflec-

tion

of 4 divisions

.

Substituting

these values in

the

vertical

conversion

factor

formula:

Vertical

Conversion

Factor

30

4X5

1.5

Then

with a VOL

TS/DIV

switch

setting

of

1, the

peak-

to-peak

amplitude

of

an

unknown

signal

, 5

divisions

high

can be

determined

by

using

the

signal

amplitude

formula

:

Signal

Amplitude:

= 1 V X 1.5 X 5 = 7.5

volts

.

TIME-DURATION

MEASUREMENTS

Obtain a Normal

Sweep

display

. Be sure the VAR

TIME

/OIV

control

is set to the

calibrated

detent. Set the

TIME/DIV

switch

for a single

event and

position

the

display

to

place

the

time

measurement

pOints

to

the

center

horizontal

graticule

line (see Fig. 18).

@

475A/OM44 Operators

37

I~

..

·

·1/

~.

..

.. ... ..

..

...

.

00

\

I I

/

I.

/ \

10/

\

/

. .

....

...

"-

V ·

HORIZONTAL

DISTANCE

1738·20

Fig. 18.

Time

duration.

Measure the

horizontal

distance

between the

time

measurement

points. Multiply

the

distance

measured

by

the setting

of

the

TIME/DIV

switch. If

sweep

magnification

is

used, divide

this

answer

by

10.

EXAMPLE : The

distance

between the

time

measure-

ment

points

is 8.3

divisions

(see Fig . 18) and the

TIME/DIV

switch

is

set to 2 ms

with

the

magnifier

off.

Using the

formula

:

horizontal

Time

Duration

distance

X

Time/Div

setting

(divisions)

magnification

Substitute

the given values:

Time

Duration

= 8.3 X 2 ms = 16.6

miiliseconds

FREQUENCY

MEASUREMENTS

Time

Duration

measurements can be used to

determine

the

frequency

of

a recurrent signal as

follows

:

1.

Measure

one

cycle

of

the waveform

as

described

in

Time-Duration

Measurements.

2.

Take the

reciprocal

of

the

time

duration

to

deter-

mine

the

frequency

.

EXAMPLE:

The

frequency

of

the signal

shown

in

Fig.

18, which

has a time

duration

of

16.6

milliseconds

is:

1

Frequency = . .

time

duration

1

16.6 ms = 60 hertz

38

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RISETIME MEASUREMENTS

Risetime

measurements

use

the

same

methods

as

time-

duration

measurements,

except

the

measurements

are

made

between

the

10% and 90%

points

of

the

waveform.

Falltime

is

measured

between

the

90% and 10%

points

on

the

trailing

edge

of

the

waveform.

Obtain a Normal

Sweep

Display.

Set A

SLOPE

to

+.

Use

a

sweep

speed

setting

that

displays

several

cycles

or

events (if

possible)

and be

sure

the

VAR

TIME/DIV

control

is in

the

calibrated

detent.

Set the

VOL

TS/DIV

switch

and

VAR

control

(or

signal

amplitude)

for

exactly a five/divi-

sion

display.

Set

vertical

positioning

so

the

display

bottom

touches

the

0%

graticule

line

and

the

display

top

touches

the

100%

graticule

line.

Set

the

TIME/DIV

switch

for a single-event

display

with

the

risetime

spread

horizontally

as

much

as

possible.

Horizontally

position

the

display

so

the

10% pOint

on

the

waveform

intersects

the

second

vertical

graticule

line (see

Fig. 19).

Measure

the

horizontal

distance

between

the

10% and

90%

points

and

multiply

the

distance

measured

by

the

setting

of

the

TIME/DIV

switch.

EXAMPLE:

The

horizontal

distance

between

the

10%

and

90%

points

is 5

divisions

(see Fig. 19)

and

the

TIME/DIV

switch

is set

to

1

J1.s.

SIGNAL

AMPLITUD

L,

I

-~

!

"-

~

-c:>

.,/

.,...,..

/

I

V

!

V

~

'I-

fJ

I

HORIZONTAL

---

DISTANCE

Fig. 19. Risetime.

----

-

-

-

ME

TIM

A

ASURE
E

FROM

TO

B

465/DM-O-13

Using

the

time

duration

formula

to

find

risetime:

Time

Duration

(risetime)

horizontal

distance

X

(divisions)

Substituting

the

given

values:

TIME/DIV

setting

Risetime

= 5 X 1

J1.S

= 5

microseconds.

@

475A/OM44

Operators 39

TIME-DIFFERENCE BETWEEN

TWO

PULSES FROM

DIFFERENT SOURCES

Obtain a Normal

Sweep Display. Make sure the VAR

TIME/DIV

control

is

in the

calibrated

detent. Set the A

Trigger

SOURCE

switch

to CH 1.

Connect

the reference

signal to CH 1 and the

comparison

signal to CH 2.

Connect

the signals to the

input

connectors

using probes

or

cables

with

equal

time

delay.

Set the VERT

MODE

switch

to

either

CHOP

or

ALT

. In

general,

CHOP

is

more

suitable

for

low-frequency

signals

and the

AL T position

is

more

suitable

for

high-frequency

signals.

Center

each

of

the

displays

vertically

(see Fig. 20).

Measure the

horizontal

difference

between the

two

signals.

Multiply

the measured

difference

by the setting

of

the

TIME/DIV

switch; if sweep

magnification

is used,

divide

this

answer

by

10.

EXAMPLE:

The

TIME/DIV

switch

is

set to

SO

IlS, the

MAG

switch

to

X10

and the

horizontal

difference

between

waveforms is

4.S

divisions

(see Fig. 20).

CHANNEL 1 (REFERENCE)

CHANNEL

2

\

r

I

\

j

.!

\

L

..

'

50%

AMPLITU

LEVEL

~

~

'

@,

I

..!

I

[

®-

I ,

I

I

I

---l

HORIZONTAL

1

___

I

DIFFERENCE

I

M

EASURE

ME

FROM

A

TO

B

TI

465/DM-O-14

Fig.

20.

Time

difference between

two

pulses

from

different

sources.

USing the formula:

Time

/Div

setting

x

horizontal
difference
(divisions)

Time

Difference

magnification

Substituting

the given values:

Time

60lls X 4.S

Difference

10

22.S

microseconds

40

475A/DM44

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TIME

COMPARISON

MEASUREMENTS

If

comparisons

of

an

unknown

signal

with

a reference

signal

are

repetitious (e.g

.,

on

assembly

line

test) it

is

possible

to

obtain

more

accurate

, easily read

measurements

if the VAR

TIME

/DIV

control

is

adjusted

to

set the

reference

signal

to an

exact

number

of

divisions

.

The

unknown

signal

can

then

be

quickly

and

easily

compared

with,

or

adjusted

to, an

exact

number

of

divisions

.

Other

unknown

signals

may

be measured

without

disturbing

the

setting

of

the VAR

TIME/DIV

control

by

establishing a horizontal

conversion

factor

and an ar-

bitrary

deflection

factor.

The

time

duration

of

the

reference

signal

must

be

known

before a horizontal

conversion

factor

can be

established.

Determine

the

horizontal

conversion

factor

using

the

formula

:

Horizontal

Conversion

Factor

reference signal

time

duration

(seconds)

Horizontal

deflection

X

(divisions)

TIME/DIV

switch

setting

Determine

the

arbitrary

deflection

factor

using this

formula:

Arbitrary

Deflection

Factor

horizontal

conversion

X

factor

TIME/DIV

switch

setting

To

measure the

time

duration

of

an

unknown

signal , set

the

TIME

/DIV

switch

to a

setting

that

provides

sufficient

horizontal

deflection

to

make

an

accurate

measurement

.

Do

not

readjust

the VAR

TIME

/DIV

control.

Measure the

horizontal

deflection

in

divisions

and

calculate

the

time

duration

using the

formula:

Time

Duration

arbitrary

deflection

factor

or

horizontal

horizontal

X

deflection

(divisions)

Time

=

conversion

X

Duration

factor

TIME/DIV

switch

setting

horizontal

X

deflection

(diVisions)

EXAMPLE:

The

reference signal

frequency

measured is

455 hertz

(time

duration

: 2.19

milliseconds)

with

a

TIME/DIV

switch

setting

of

.2

ms, and the VAR

TIME/DIV

control

adjusted

to

provide a horizontal

deflection

of

eight

@

475A/ OM44 Operators

41

divisions. Substituting

these values in the

horizontal

conversion

factor

formula

:

Horizontal

Conversion

Factor

2.

19ms

8 X 0.2 ms

1.37

Then

with

a TI ME/DIV

switch

setting

of

50

jJS,

the

time

duration

of

an

unknown

signal

that

completes

one

cycle

in

seven

horizontal

divisions

, can be

determined

by using the

time

duration

formula:

Time

Duration

= 1.37 X 50

jJs

X 7 = 480

jJs

This

answer

can be

converted

to

frequency

by

taking

the r

eciprocal

of

the

time

duration

(see

applications

on

Determ

ining

Frequency)

.

PHASE

DIFFERENCE

MEASUREMENTS

Use

either

the

CHOP

or

AL T mode

. Set the A

TRIGGER

SOURCE

switch

to

CH

1. The reference

signal

should

precede the

comparison

signal in

time

. Use

coax

ial cables

or

probes

that have

equal

time

delay

to

connect

the signals

to the

input

connectors

.

If the

signals

are

of

opposite

polarity

, set

the

INVERT

pushbutton

to

invert

the

Channel2

display

(signals

may

be

of

opposite

polarity

due

to 1800 phase

difference; if

so ,

take this

into

account

in the final

calculation)

. Set the

CH

1

and

CH

2 VOL TS/DIV

switches

and the

CH 1 and

CH 2

VAR

controls

so the

displays

are

equal

in

amplitude

.

Set the

TIME

/DIV

switch

for

about a one-cycle

waveform.

Position

the

display

and

turn

the

A VAR

TIME

/DIV

control

for

1 reference

signal

cycle

in

exactly

eight

divisions

(see Fig. 21) . Each

division

of

the

graticule

represents 45°

of

the

cycle

(360°

-:--8 divisions

=

45

° Idivision). The sweep rate can be stated in terms

of

degrees

as

45° I

division

.

Measure the

horizontal

difference

between

correspon-

ding

pOints on the

waveforms

and

multiply

the

distance

measured (in

divisions)

by

45° I

division

(sweep rate) to

obta

in the

amount

of

phase

difference.

EXAMPLE:

The

horizontal

difference

is 0.6 divi

sion

with

a sweep rate

of

45° I

division

as

shown

in Fig. 21.

42

475A/OM44 Operators

@

I
I

.1

I

I
I

I
I

I

I
I

I

I

I

I

I

I

I

I

1-1

...

___

8

DIVISIONS

-----11-1

(360

0

)

Fig. 21. Phase

difference

.

Using

the

formula

:

MEASURE

TIME

FROM

A

TO

B

HORIZONTAL

DIFFERENCE

465/DM-O-15

Phase

Difference

horizontal
difference

divisions

X

sweep

rate

(degrees/div)

Substituting

the

given

values:

Phase

Difference

= 0.6 X 45° =

2YO

.

HIGH

RESOLUTION PHASE

DIFFERENCE MEASUREMENTS

Make

more

accurate

phase

measurements

by

in-

creasing

the

sweep

rate

(without

changing

the

A VAR

TIME/DIV

control)

by

using

the

X10

MAG

mode

. Delayed

sweep

magnification

may

also

be used (see Fig. 22) .

CHANNEL

2

'; -

-l-

--I--I---I-

+-j--f--I--

f--

I

HORIZONTAL

I

r--

DIFFERENCE

--J

MEASURE

TIME

FROM

A

TO

B

465/DM-O·16

Fig. 22.

High-resolution

phase

difference

.

@ 475A/DM44 Operators

43

EXAMPLE: If the sweep rate

were

increased 10 times

with

the

magnifier

, the

magnified

sweep

rate

would

be45

°

-:-

10 = 4.5

°/

division

. Fig .

22

shows

the same

signals

as

used in Fig.

21

but

with

the X10

MAG

switch

set

to

X10.

With a horizontal

difference

of 6 divisions

, the phase

difference

is:

Phase

horizontal

magnified

Difference

difference

X

sweep rate

(divisions)

(degrees/div)

Substituting

the

given values:

Phase

Difference

= 6 X 4.5° =

27

°.

PULSE

JITTER

MEASUREMENTS

Be sure the VAR

TIME/DIV

switch

is in the

calibrated

detent. Set the B

TIME/DIV

swi

tch

to

intensify

the full

rising

portion

of the

pulse

. Set the

HOR

IZ

DISPLAY

switch

to B DLY'D

.

,.

r

'i

MEASURE

TIME

FROM

A

TO

B

1

I I

I

I I

\-

-t-

--I-~

I !

I I

--l

~-

JITTER

Fig. 23. Pulse

jitter

.

1738-34

Pulse

jitter

is

shown

by

horizontal

movement

of

the

pulse

and

includes

the

inherent

jitter

of

the Delayed

Sweep

(see Fig. 23).

Multiple

the

distance

by

the B

TIME/DIV

switch

setting

to

obtain

pulse

jitter

time

.

44

475A/OM44 Operators

@

I
I

I

I

I

I

I

I

I

I
I

I

I

I

I

I

I

I

DELAYED OR

MIXED

SWEEP

MAGNIFICATION

The

delayed

sweep

features

of the

475A

can be used to

provide

higher

apparent

magnification

than

is

provided

by

the

X1 0 MAG

switch.

The

sweep

rate

of

the

delayed

sweep

(B

sweep)

is

not

actually

increased;

the

apparent

magnification

is

the

result

of

delaying

the B sweep

in an

amount

of

time

selected

by

the A TIME/DIVswitch

and

the

DELAY-TIME

POSITION

control

before

the

display

is

presented

at

the

sweep

rate

selected

by

the B TIME/DIV

switch.

The

following

method

uses the

STARTS

AFTER

DELAY

position

of

the B Trigger

SOURCE

switch

to

allow

the

delayed

portion

to

be

positioned

with

the

DELAY-

TIME

POSITION

control.

If

there

is

too

much

jitter

in the

delayed

display,

use the

Triggered B Sweep

mode

of

operation.

Magnified Sweep Starts After Delay

1.

Connect

the

signal

to

either

input

connector.

Set

the

VERT

MODE

switch

to

display

the

channel

used.

2.

Set

the

VOL

TS/DIV

switch

to

produce a display

about

four

divisions

in

amplitude.

3.

Set

the A TIME/DIV

switch

to

a sweep rate

which

displays

the

complete

waveform.

4.

Set

the

HOR IZ

DISPLAY

switch

to A INT

and

the

B

Trigger

SOURCE

switch

to

STARTS

AFTER

DELAY.

Instrument

equipped

with

DM44.

Verify

that

the

FUNC-

TION

switch

is

not

set

to

TIME

or

1ITIME.

5.

Position

the

start

of

the

intensified

zone

with

the

DELAY-TIME

POSITION

control

to

the

part

of

the

display

to

be

magnified.

6.

Set the B

TIME/DIV

switch

to a setting

which

intensifies

the full

portion

to

be

magnified.

The

startofthe

intensified

zone

remains

as

positioned

above

(see Fig. 24).

7.

Set

the

HORIZ

DISPLAY

switch

to B DLY'D

to

magnify

the

portion

of A sweep

that

is

intensified

(see Fig.

24).

8.

Time

measurements

can be

made

from

the

display

in

the

conventional

manner.

The

sweep

rate is

determined

by

the

setting

of

the B TIME/DIV

switch.

9.

The

apparent

sweep

magnification

can be

calculated

by

dividing

the A TIME/DIV

switch

setting

by

the B TIME/DIV

switch

setting.

@

475A/DM44

Operators

45

INTENSI FI

ED

ZONE

TO

BE

MI\,.GNIFIED

J .

...

~

..;

"-

\

\

,.

I

I

....

IA) A INTENSI

FI

ED

DISPLAY

L

'00

-,

,

..

V\.

~

.

17

,.

/

I

.

':--

.

I' .

~

.

~

....

/"

~

EXAMPLE:

The

apparent

magn

ifi

cation

of a display

I

with

an A

TIME/DIV

switch

setting

of

.1

ms and a 8

TIME

/DIV

switch

setting

of 1 jJs

is:

Apparent

Magnification

_

(Delayed -

Sweep)

A

TIME

/DIV

setting

8

TIME

/DIV setting

Substituting

the given values:

Apparent

Magnification

X 10--

X 10 '

The

apparent

magnification

is

100 times.

Triggered Delayed Sweep Magnification

The'delayed sweep

magnification

method

just

describ-

ed

may

produce

too

much

jitter

at

high

apparent

I

I

I

I

I

I

(BI B

DELAYED

DISPLAY

......

___________________

.....:..;.17.:..:38;..:.3..:.JI

magnification

ranges .

Operating

the 8 Sweep in a

I

Fig . 24. Delayed sweep

magnification.

46

triggered

mode

provides a

more

stable

display

since the

delayed

display

is

triggered at the same

point

each time.

475A/DM44 Operators

@

I

I

I

I

I

I

I

I

I

I

1.

Set

up

the

display

as given in steps 1

through

6

under

"Magnified

Sweep Starts

After

Delay."

2. Set

the B Trigger

SOURCE

switch

to the same

position

as the A

Trigger

SOURCE

switch.

3.

Adjust

the B LEVEL

control

so

the

intensified

zone

on

the

trace

is stable.

(If

an

intensified

zone

cannot

be

obtained,

see step 4.)

4.

Inability

to

intensify

the

desired

portion

indicates

that

the

signal

does

not

meet

the

triggering

requirements.

If the

condition

cannot

be

remedied

with

the B

Triggering

controls

or

by

increasing

the

display

amplitude

(lower

VOL

TS/DIV

setting),

trigger B Sweep

externally

.

5. When the

correct

portion

is

intensified,

set the

HORIZ

DISPLAY

switch

to B DLY'D.

Slight

readjustment

of

the B LEVEL

control

may

be necessary

for

a stable

display.

6.

Measurements

are

made

and

magnification

factors

are

calculated

as in

the

STARTS

AFTER

DELAY

mode

previously

given.

@

475A/OM44 Operators

47

BASIC 475A DELAYED OR

MIXED

SWEEP

TIME

MEASUREMENTS

The

delayed sweep

modes

can be used

to

make

more

accurate

time

measurements

.

TIME

DIFFERENCE

BETWEEN

REPETETIVE PULSES (BASIC 475A)

Obtain

a Delayed Sweep

Display

. For the

most

accurate

measurement,

set the B

TIME/DIV

switch

to

the fastest

sweep speed that gives

usable

(visable)

intensified

zones.

With the

HORIZ

DISPLAY

switch

set to A

INTEN

, use

the

DELAY

TIME

POSITION

dial

to

move the

intensified

zone

to the first pulse (see Fig. 25A) .

Set the

HORIZ

DISPLAY

switch

to 8 DL

y'D. Adjust

the

DELAY

TIME

POSITION

dial

to

move

the pulse

(or

rising

portion)

to

some

vertical reference

line

(see Fig.

258).

Note

the

setting

of

the

DELAY

TIME

POSITION

dial.

Turn

the

DELAY

TIME

POSITION

dial

clockwise

to

move the

second

pulse

to

the

same vertical reference

line

(if

several

pulses

are

displayed

, return to A

INTEN

to locate the

correct

pulse) .

Do

not

change

the settings

of

the

horizon-

tal

POSITION

and FINE

controls. Note

the

setting

of

the

DELAY

TIME

POSITION

dial.

Determine

the time

difference

using

the

following

formula:

Time

Difference

=

dial

~

econd

dial

setting

firstJ

setting

delay

time

X A

TIME/DIV

setting

EXAMPLE:

Assume

the

first

dial

setting

is 1.

31

and the

second

dial

setting

is 8.

81

with

the A

TIME/DIV

switch

set

to

0.2

{JS

(see Fig . 25).

Using

the

formula:

Time

Difference

=

[

Second.

dial

_ first

dial]

delay

time

X (A

TIME/DIV

setting

setting

setting)

48

475A/DM44 Operators

@

I
I

I

I

I
I
I

I

I
I

I
I

I

I

I
I

I

,~

90

®--

---..

I

A) A DISPLAY

-

"

I

~

'

,

L

'00

..

,.

I

I

18

) 8 O LY' D

DISPLAY

~

'\

"

I

TI~E

DIFFEREN

CE

III"

1/

1\

/

~

1\

./

!"

,

~INT~~~~IED.?:'

,

i

VERTICAL

/REFEREN

CE

LINE

1""-

A OR 8

~

~

17)8 ·

23

Substituting

the given values:

Time

Difference

= (8.

81-1.31)

XO.2f../s

.

The

time

difference

is 1.5

microseconds

.

TIME

DURATION

MEASUREMENTS

(BASIC 475A)

Obtain

a Delayed

Sweep

Display. Set

the A TIME/DIV

switch

to

display a single

event. Be sure the VAR

TIME/DIV

control

is in

the

calibrated

detent

. For the

most

accurate

measurement,

set

the B TIME/DIV

switch

to

the

fastest sweep speed that gives a usable (visible)

inten-

sified

zone. Vertically

position

the

display

to place the

time

measu rement points to the

center

horizontal

g raticu

Ie

line

(see Fig. 26).

Use the DELAY

TIME

POSITION

dial

to

move

the start

(left-hand

edge)

of

the

intensified

zone

to

just

touch

the

intersection

of

the signal and the

center

horizontal

graticule

line

(see Fig. 26,

Point

A).

Note

the DELAY TIME

POSITION

dial

setting

.

Fig. 25.

Time

difference

between

repetitive

pulses.

Use the DELAY

TIME

POSITION

dial to move the start

of

the

intensified

zone

to

the

second

time

measurement

point

(see Fig. 26,

Point

B).

Note

the DELAY

TIME

POSITION

dial

setting

.

@

475A/DM44

Operators

49

~~~~~~~~

-

~

I

HORIZONTAL

I

1..1

....

__

DISTANCE

--

.....

~I

Fig_

26_

Time

duration.

465/DM-O-9

Substitute

the

DELAY

TIME

POSITION

dial

settings

into

the

time

difference

formula

to

obtain

the

time

duration.

EXAMPLE:

The A TIME/DIV

switch

is set

to

2 ms and

the B TIME/DIV

switch

is set to .1 ms.

The

DELAY

TIME

POSITION

dial

setting

at

Point

A

(Fig . 26) is

1.20.

The

DELAY

TIME

POSITION

dial

at

Point

B (Fig. 26) is 9.53.

To

find

the

time

duration

use

the

formula:

Time

Time

Difference

Duration

[

,ecood

f;,,,

J

delay

time

dial

dial

X

(A

TIME/DIV

setting

setting

setting)

Substituting

the

given

values :

Time

Duration

= (9.53 - 1.20) X 2

ms

= 16.66 ms

FREQUENCY

MEASUREMENTS

(BASIC

475A)

The

frequency

of a recurrent

signal

can be

calculated

by

taking

the

reciprocal

of

the

time

duration

of

one

event.

EXAMPLE: The

time

duration

of

one

event

(Point A to

Point

B, Fig. 26) is 16.66

milliseconds

.

Using

the

formula

:

Frequency

=

--~--:--

time

duration

Substituting

the given values:

1

Frequency

= 16.66 ms

60

hertz

50

475A/OM44 Operators

@

I
I

I

I

I

I
I
I

I

I

I

I

I

I

I
I
I

I

TIME

DIFFERENCE

BETWEEN

TWO

PULSES FROM

DIFFERENT

SOURCES

(BASIC 475A)

Make

sure

the

VAR

TIME/DIV control

is in

the

calibrated

detent.

Set

the A Trigger

SOURCE

switch

to

CH

1.

Connect

the reference

signal

to

CH 1 and

the

com-

parison

signal

to

CH

2.

Conne

ct

the

signals

to

th e

input

connectors

using

probes

or

cables

with

equal

time

delay

.

CHANNEL 1 (REFERENCE)

""

I

f\-.

.

~I

~

V

1

~:

"'-

j.L

""

50

%

PLiTUDE

~

EVEL

AM

L

t ')II.

"-

100-:

1

I

A

I

I

1---"': ..

~

INTENSIFIED

II

-

ZONE

Ii

I

I

-l

HORIZONTAL

L-,

I

DIFFERENCE

/

CHANNEL2

M
TI

EASURE

ME

F

ROM A TO

B

Set

the

VERT

MODE

switch

to

either

CHOP

or

ALT

. In

general, CHOP

is

more

suitable

for

low-frequen

cy

signals

and

the

AL T position

is

more

suitable

for high-frequen

cy

signals. Center

each

of

the

displays

verti c

ally

(see Fig.

27A).

Set

the

HORIZ

DISPLAY swi

tch

to A INT

and

the B

Trigg

er

SOURCE

to

STARTS

AFTER

DELAY

. Set

the

B

TIME/DIV

switch

20

times

faster

than

the A TIME/DIV

swit

ch

(when

possibl

e).

VERTICAL

REFERENCE

LINE

_____

I I -1

,.!

CH 2

SIGNAL

'1

\1

CH 1

SIGNAL

I

!

\

I

CHl

SIGNAL

1\

A

FO

~

CH 1

,

B

FOR

CH 2

i

,.

I I

L

I

ONLY

ONE

OF

THE

ABOVE

DISPLAYS

CAN

BE

POSITIONED

TO

CENTER

ON

INSTRUMENTS

WITHOUT

DM

40

SERIES. 1738-10

Fig

. 27.

Time

difference

between

two pulses

from

different

sources.

@

475A/OM44

Operators

51

Use

the

DELAY

TIME

POSITION

dial

to

move

the

intensified

zone

to

the

CH

1 pulse. Set

the

HORIZ

DISPLAY

switch

to 8 DLY'D.

Readjust

the

DELAY

TIME

POSITION

dial

to

move

the

CH 1 pulse

or

rising

portion

to

some

vertical

reference

line

(see Fig.

278).

Note

the

DELAY

TIME

POSITION

dial

setting.

Use the

DELA

Y TI ME POS

ITION

dial

to

move

the

CH 2

pulse

or

rising

portion

to

the

same

reference

line.

Again

note

the

DELAY

TIME

POSITION

dial

setting

.

Substitute

the

DELAY

TIME

POSITION

dial

settings

in

the

time

difference

formula

to

find

the

time

difference

.

EXAMPLE:

The A TIME/DIV

switch

is set

to

50

ps

and

the 8 TIME

/DIV

switch

is set to 2 ps. Use

the

DELAY

TIME

POSITION

dial

to

move

the

CH 1 pulse

to

the

reference

line.

The

DELAY

TIME

POSITION

dial

setting

is 2.60.

Use the

DELAY

TIME

POSITION

dial

to

move

the

CH 2

pulse

to

the

reference

line

. The

DELAY

TIME

POSITION

dial

setting

is 7.10.

To

find

the

time

difference

use

the

formula

:

[

second

first]

delay

time

Time

=

dial

dial

X (A

TIME/DIV

difference

setting setting

setting)

Substituting

the

given

val ues:

Time

Difference

= (7.10 - '2.60) X 50

ps

= 225

ps

RISETIME

(BASIC

475A)

R isetime measu rements use the

same

methods

as

time-

duration

measurements,

except

the

measurements

are

made

between

the 10%

and

90%

points

of

the

waveform

.

Falltime

is

measured

between

the

90%

and

10%

points

on

the

trailing

edge

of

the

waveform.

Use

a sweep speed

setting

that

displays

several

cycles

or

events (if

possible)

and be sure

the

VAR

TIME

/DIV

control

is

in the

calibrated

detent.

Set the

VOL

TS /DIV

switch

and the VAR

control

(or

signal

amplitude)

for

exactly a five-division

display.

Set

vertical

positioning

so

the

display

bottom

touches

the

0%

graticule

line

and

the

display

top

touches

the

100%

graticule

line

(see Fig . 28).

Set the A

TIME

/DIV

switch

for a single-event display

with

the

risetime

spread

horizontally

as

much

as

possible

.

Horizontally

position

the

display

so the 10%

point

of

the

waveform

intersects

the

second

vertical

graticule

line (see

Fig. 28) . Set

the 8 TIME/DIV

switch

to

the

fastest sweep

speed

that

provides a usable

(visible)

intensified

zone

.

Use

the

DELAY

TIME

POSITION

dial

to

move

the

start

of

the

intensified

zone

(left-hand

edge) to

just

touch

the

intersection

of

the

signal

and

the

10%

graticule

line

(see

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Fig. 28,

Point

A). Note

the

DELAY

TIME

POSITION

dial

setting

.

Use

the

DELAY

TIME

POSITION

dial

to

move

the

start

of

the

intensified

zone

to

just

touch

the

intersection

of

the

signal

and

the 90%

graticule

line

(see Fig. 28,

Point

B).

Note

the

DELAY

TIME

POSITION

dial

setting

.

Substitute

the

DELAY

TIME

POSITION

dial

settings

in

the

time

difference

formula

to

find

the

risetime.

SIGNAL

AMPLITUDE

-~

INTENSIFIED

ZONES

HORIZONTAL

I

DISTANCE

I-

MEASURE
TIME
FROM A TO

B

(4

6 5 /DM·0 -

ll )2039·29

Fig. 28. Risetime.

EXAMPLE:

The A TIME/DIV

switch

is set

to

1 /1S. The

DELAY

TIME

POSITION

dial

setting at

point

A (Fig . 28) is

2.50

The

DELAY

TIME

POSITION

dial

setting

at

point

B

(Fig. 28)

is

7.50.

To

find

the riseti

me

use

the

formula

:

Time

R"

D

'ff

= Isetlme =

I

erence

[

second

dial

setting

first

]

dial

setting

Substitut

ing

the

given values:

delay

time

X (A

TIME/DIV

setting)

Risetime = (7

.50 - 2.50) X 1 /1S = 5 ms.

MIX

(BASIC 475A)

For

the MIX

mode

of

operation,

the same general

procedures

can be used. With the first

part

of

the

display

at

a sweep rate set

by

the A

TIME

/DIV

switch

and the second

part

of

the

display

at a

sweep

rate set

by

the B

TIME

/DIV

switch

, it is not necessary to

switch

display

modes

to

ensure

location

of

the

correct

pulse .

However. inaccuracies

are

introduced

into

the

measurement

by

the

transition

from A

to

B sweeps.

The

B

DL

Y'D

mode

is the

most

accurate

and

therefore

recommended

mode

of

making

differential

time

measurements

.

@ 475A/OM44 Operators

53

DM44 DELAYED OR MIXED SWEEP

TIME

MEASUREMENTS

I

Most

measurements

of

time,

time-duration, frequency,

time

difference

and

risetime are

more

easily

performed

using

the

TIME

function

of

the DM44 and the

delayed-sweep

mode

of

the

oscilloscope

. Table 5 lists the DM44

and

oscilloscope

I

operating

modes

and the

crt

display

obtained

in these modes.

TABLE

5

DM44

Delayed

Sweep

Displays

DM44

HORIZ

VERT

I

FUNCTION

DISPLAY

MODE

DISPLAY

OBTAINED

CH

1,

CH 2,

One

intensified

zone,

DELAY

TIME

POSITION

moves

intensified

zone

.

OR

ADD

I

A

INTEN'

ALT

or

Two

intensified

zones,

one

on each

channel

display. Intensified

zones

I

VOLTS

CHOP

are

coincide.,t

in

time. DELAY

TIME

POSITION

moves

both

intensified

OHMS,

zones .

OR

TEMP

CH

1,

CH

2,

OR

ADD

One

mixed

display

. Position

of

transition

point

determined

by

DELAY

I

TIME

POSITION

.

MIX

ALT

OR

Two

mixed

displays, one

on each

channel

display.

Transition

pOints are

I

CHOP

coincident

in time. Position

of

transition

points

determined

by

DELAY

TIME

POSITION

.

I

'In

the B DLY'D

mode,

the

intensified

zones

(that

are

displayed

In the A

INTEN

mode)

will

be

displayed

at

the B sweep

rate .

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TABLE 5 (cont)

DM44

Delayed

Sweep

Displays

DM44

HORIZ

VERT

FUNCTION

DISPLAY

MODE

DISPLAY

OBTAINED

CH

1,

CH

2

Two

intensified

lone

s.

DELAY TIME

POS I

TION

mov

es

both intensified

OR

ADD

lones

. ~ TIME

moves

only one

intensified

zone

.

A

INTEN

2

All

Two

intensified lones. Reference

point

appears

on

CH 1 display.

Measurement

point

appea

rs

on

CH 2 display. DELAY

TIME

POSITION

moves

both

intensified

zones . ~ TIME

moves

only

the

measurement

point

(on the

CH 2 display)

.

TIME

Two

pairs

of

intensified

lones,

one

pair

on

each

channel

display. The

pairs

OR

CHOP

are

coincident

in

time

with

each

other

DELAY

TIME

POSITION

moves all

1fTIME

"-

four

intensified

lones

. ~ TIME

mov

es

two

intensified

lones

.

CH

1,

CH

2,

Two

mixed

dis pla ys,

one

on

each channel d

isplay. DELA Y TIME

POSITION

OR

ADD

moves

transition

point

of

both

displays. /:;

TIME

moves

transition poi

nt

of

CH 2 display

only

.

All

Two

mixed

displays, one

on

each

channel display. DELAY

TIME

POSI-

tion

moves

transition

point

of

both

displ

ays

AL T DELA

Y moves tran-

MIX

sition

point

of

CH 2 display

only.

..

.-

CHOP

Four

mixed

displays,

two

on

each

channel

display. Not

generally

used

since

mixed

displays

overlap.

'Your

instrument

may

be

modified

to

make

the

DELAY

TIME

POSITION

and

6.

TIME

controls

operate

independently. The

instructions

for

making

this

modification

are

located

In

the

Maintenance

section

of

the

DM44

Service

manual

.

@

475AfDM44

Operators

55

TIME

DIFFERENCE BETWEEN

REPETITIVE PULSES (DM44)

Set the

controls

as

follows:

FUNCTION
HORIZ

DISPLAY

8

SOURCE

A

TIME/DIV

8

TIME/DIV

A

TIME

VAR

TIME/DIV

TIME
AINTEN
STARTS

AFTER

DELAY

To

display

2 pulses

3

or

4 positions

more

cw

than A TIME/DIV

To

move

the

time-

measurement

point

to

the

right

of

the

ref-

erence

pOint

Detent

position

Position

the

display

approximately

as

shown

in Fig.

29A. Use the

DELAY

TIME

POSITION

control

to move the

reference

pOint to the fi rst

pulse. 80th

intensified

zones

will

move when the

DELAY

TIME

POSITION

control

is

adjusted. Use the A

TIME

control

to move the

time-

measurement

pOint to the

second

pulse

.

Set

the

HORIZ

DISPLAY

switch

to 8

DLY'D. Slightly

readjust

the A

TIME

control

to

superimpose

the

waveforms

(see Fig.

298)

. The

DELAY

TIME

POSITION

control

may need to be

slight

ly readjusted to keep the

display

on

screen . The

Readout

and Scale

Factor

Lamps

now

indicate

the

time

difference

between the pulses.

--1-

TIME

r-

r--

,~

...

DIFFERENCE

90

®--

-

II!:

~

b

r\

lL

1&

1\

/

r-

"

~INTENSI

F I ED

".

,.

'-,

./

I

t

. .

(A) A DISPLAY

1

,.

I

1

(B) B

DL

Y'D

DISPLAY

ZONES

1

VERTICAL

/REFERENCE

LINE

1'-.

A

AND

B

SUPERIMPOSED

(1738-23)2039-30

Fig.

29.

Time

difference

between

repetitive pulses.

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find

the

pulse

repetition

rate ,

superimpose

the

waveforms

as

above

and

set the

FUNCTION

switch

to

1/

TIME. The

Readout

and

Scale

Factor

Lamps

now

indicate

the

repetition

rate.

TIME

DURATION

MEASUREMENTS

(DM44)

Set

controls

as

follows

:

FUNCTION
HORIZ

DISPLAY

B

SOURCE

A

TIME/DIV

B

TIME/DIV

l:::"

TIME

VAR

TIME/DIV

TIME
A

INTEN

STARTS

AFTER

DELAY

To

display a single

event .

3

or 4 positions

more

cw

than A

TIME/DIV

To

move

the

time-

measurement

point

to

the

right

of

the ref-

erence

point.

Detent

position

Use

the

DELAY

TI ME

POSITION

control

to

move

the

reference

point

to a

horizontal

graticule

line

(see Fig . 30A,

Point

A). Use the

l:::"

TIME

control

to

move

the

time-

(A) A SWEEP

DISPLAY

(B) B

DLY'D

DISPLAY

2039-31

Fig. 30.

Time

duration

and

frequency

measurements.

@

475A/OM44

Operators

57

measurement

point

to near the same

horizontal

graticule

line

on

the next

cycle

of

the

waveform

(see Fig . 30A,

Point

B).

Set the

HORIZ

DISPLAY

switch

to B DLY'D.

Slightly

readjust the

t::.

TIME

control

to

superimpose

the displayed

waveform

portions

(see Fig. 30B). The DELAY.

TIME

POSITION

control

may

need to be

slightly

readjusted to

keep the

display

on

screen. The Readout and Scale

Factor

Lamps indicate the time

duration

.

FREQUENCY

MEASUREMENTS

(DM44)

To

measure frequency, use the same

procedure

as for

Time

Duration

Measurements

except

set the

FUNCTION

switch

to

1/TIME.

With

the

display

superimposed

the

Readout and

Scale

Factor

Lamps indicate the

frequency

.

The

Scale

Factor

Lamps indicate the scale

factor

as

follows:

1/ms

Lamp

1/11s

Lamp

Multiplier

OFF OFF Hz

ON

OFF

kHz

OFF ON

MHz

A

blinking

display

indicates

an

over-range

condition

.

This

occurs

on measurements as

follows:

A Time/Dlv Set To Decade Spacing Between Intensified

Multiples

of Zones Less Than

0.25 DIV

2

0.5 DIV

5

1.0 DIV

TIME

DIFFERENCE BETWEEN

TWO

PULSES

FROM

DIFFERENT

SOURCES

(DM44)

Set

controls

as follows:

A

SOURCE

VERT

MODE

HORIZ

DISPLAY
B SOURCE
B

TIME/DIV

VAR

TIME/DIV

CH

1
ALT
A INT
STARTS

AFTER DELAY

3

or 4 positions

more

cw

than A

TIME/DIV

Detent

position

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Connect

the

reference

signal

to

the

CH 1 i

nput

and

the

comparison

signal

to

the CH 2

input. Connect

the

signals

to

the

inputs

with

cables

or

probes

having

equal

time

delays

.

Adjust

the

DELAY

TIME

POSITION

control

to

move

the

reference pOi

nt

to

the

desired

spot

on

the

reference

(CH 1)

display

(see Fig. 31A,

Point

A). In

the

AL T vertical

mode

the

reference

point

appears

on

the

CH 1 display

while

the

time-measurement

pOint

appears

on

the

CH 2

display

.

CHANNEL 1 (REFERENCE)

CHANNEL

2

50

%

AMP

LI

TU

D E

-!-+---~

-+-Pl-r-

-+-

-t------,

LEVEL

i

MEASURE

r--

+-I--=::~

c---~..cL+-+--

----+

-

TI M E

INTENSIFIED

-t--_I--:-

---c

FROM

A

TO

B

~'-"""'d-

ZONES

I

-.l

HORIZONTAL

t--.

I

DIFFERENCE

Adjust

the

t::.

TIME

control

to

move

the

time

-

measurement

pOint to the

desired

spot

on

the CH 2

display

(see Fig.

31A, Point 8).

Set

the

HORIZ

DISPLAY

swi

tch

to 8 DLY

'D.

Slightly

readjust

the

DELAY

TIME

POSITION

and

t::.

TIME

controls

to

superimpose

the

waveforms

(see Fig.

318). The

Readout

and Scale

Factor

Lamps

indicate

the

time

difference

.

(465/DM

·0 ·

'0)2039·32

Fig . 31.

Time

difference

between

two

pulses

from

different

sources.

@

475A/OM44

Operators

59

RISETIME

(OM4,4)

Set

controls

as

follows:

FUNCTION
HORIZ

DISPLAY

B

SOURCE

B

TIME/DIV

l:l.

TIME

TIME

A

INTEN

STARTS AFTER DELAY

3

or 4 positions

more

cw

than A

TIME

/DIV

To

move the

time-

measurement

pOint

to the

right

of

the

reference

pOint

Set

the A

TIME

/DIV

switch

to a setting that displays

several

events. Set the

VOL

TS/ DIV

and

VAR

VOL

TS/DIV

so the

amplitude

of

the

display

is

exactly 5 divisions

.

Vertically

position

the

display

so the

bottom

touches

the

0%

graticule

line and the

top

touches

the 100%

graticule

line.

Adjust

the

DELAY

TIME

POSITION

control

to

move

the

reference

pOint

to

the 10%

graticule

line

(see Fig. 32

Point

A).

Adjust

the

l:l.

TIME

control

to

move

the

time

measure-

ment

point

to the 90%

graticule

line

(see Fig. 32,

Point

B).

The

Readout and Scale

Factor

Lamps

indicate

the

risetime.

INTENSIFIED

ZONES

I

1

SIGNAL

AMPLITUDE

I

1

-~

'

t-

1I

I

--I

1""-

II

'\~

J

'\

.-

~

./

V

.~

V

®~

/

V

F'@

I . t

HORIZONTAL

I

DISTANCE

I--

-

M

-TI

EASURE

ME

F

ROM A TO

B

i

(465/DM-0-ll

'2039-29

Fig

. 32.

Risetime

.

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MIX

(OM44)

For

the

MIX

mode

of

operation,

the

same

general

procedures

can

be

used.

With

the first

part

of

the

display

at

a

sweep

rate set

by

the A

TIME/OIV

switch,

and

the

second

part

of

the

display

at a

sweep

rate set

by

the B

TIMEIDIV

switch,

it is

not

necessary to

switch

display

modes

to

ensure

location

of

the

correct

pulse.

However,

inaccuracies

are

introduced

into

the

measurement

by

the

transition

from

A to B sweeps.

The

B

OL Y'O

mode

is

the

most

accurate

and

therefore

the

recommended

mode

of

making

differential

time

measurements.

@

475A/OM44

Operators

61

OPERATOR'S

SPECIFICATIONS

Refer to the service manual

for

complete

specifications.

Specifications

given are

for

an

operating

range

of

O°C to

+40°

C unless

otherwise

stated.

475A

OSCILLOSCOPE

VERTICAL

Deflection Factor Accuracy:

Within

3%

in the

calibrated

position

.

Frequency Response: Dc to at least 250

MHz

for

CH

1

and

CH

2.

AC-coupled,

low-frequency

response is 10 Hz

or

less. Use

of

a 10X

probe

extends

frequency

response to

1 Hz.

Risetime: 1.4

nanoseconds

or

less

(calculated

from

0.35

-:-

bandwidth

in MHz).

Maximum Input Voltage:

Dc-coupled

250 V (dc + peak

ac)

or

500 V

p-p

ac at 1 kHz

or

less;

ac-coupled,

500 V

(dc

+ peak ac)

or

500 V p-p ac 1 kHz

or

less.

Positive-Going Step Aberrations: Less

than

+3%,

-3%,

not to exceed

3%

peak-to

-peak,

excluding

the

ADD

mode.

Common-Mode

Rejection Ratio

(ADD

Mode with

CH

2

Inverted): At least 10:1 at 20

MHz

for

common

mode

signals of 6

divisions

or

less with

GAIN

adjusted

for

best

CMRR at

50

kHz.

Input Gate Current: 0.5

nA

or

less (0 .1

div

at

5

mV/DIV),

from -

15°C

to

+30°C.

Channel Isolation: At least 100:1 at

25

MHz

.

CHOP

Mode Repetition Rate:

Approximately

250 kHz.

Cascaded Operation

(CH 2 OUT

into

CH

1)

sensitivity:

Approximately

2.5

mV/DIV. Bandwidth

is

dc

to at least

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50

MHz, with

CH 2 OUT

connected

to

CH 1 input.

AC-

coupled, using a 500,

42-inch

BNC

cable, terminated

in

50 0 at

CH 2 Input.

TRIGGERING

Sensitivity

Ac Coupled Signal: 0.3

div

internal

or

50

mV

external,

from

60 Hz to

25

MHz; increasing

to 1.5 div,

internal

or

150 mV

external

at 100

MHz

.

LF REJ Coupled

Signal: 0.5

div

internal

or

100 mV

external,

from

50 kHz

to

25

MHz; increasing

to 1.5

div

internal

or

300

mV

external

at 100

MHz. Attenuates

signals

below

about

50

kHz

.

HF

REJ Coupled Signal: 0.5

div

internal

or

50 mV

external, from

60 Hz

to

50

kHz. Attenuates

signals

below

about

50 Hz

and

above

about

50

kHz

.

DC

Coupled Signal: 0.3

div

internal

or

50

mV

external,

from

dc

to 25

MHz;

increasing

to 1.5

div

internal

or

150 mV

external

at 100 MHz.

EXT

-:-

10 Signal:

Amplitude

requirements

are

mul-

tiplied

by

10.

External Trigger Input

Maximum Input Voltage: 250 V

(dc

+ peak ac)

or

250 V

p-p

ac

(1

kHz

or

less).

Level Control Range

in

Ext .

At

I~ast

+ and

-2

V,

4 V p-p;

EXT..:..

10 is at least + and

- 20

V,

40 V

p-p

.

Trigger View

Deflection Factor:

About

50

mV/div

in EXT and

about

500

mV/div

in

EXT..:...

10.

Rlsetime: 5 ns

or

less.

Trigger Centering Point:

Within

1.0

division

of

screen

center

.

DIFFERENTIAL

TIME

MEASUREMENT

(BASIC 475A)

Accuracy for Measurements Greater than One Major

Dial Division:

Within

±1%

from

+15

°C

to

+35°C.

Within

+1.5%

from

-15°C

to

+55°C.

@

475A/DM44

Operators

63

Accuracy

for

Measurements

Less

than

One

Major

Dial

Division:

Within

±0.01

major

dial

divisions

from

+15

° C to

+35°C.

Within

± 0.

02

major

dial

divisions

from

-15°C

to

+55°C.

DIFFERENTIAL

TIME

MEASUREMENT

(DM44)

Refer to

TIME

AND

1/TIME

under

DM44

DIGITAL

MUL

TIMETER

.

HORIZONTAL

Sweep Rate

Accuracy:

Within 2%,

unmagnified

, and

3%

magnified,

from

+20

°C to

+30°C

for

A and 8 Sweeps .

Mixed

Sweep

Accuracy:

With in

2%

plus the measured A

Sweep

inaccuracy,

when

viewing

the A

portion

only.

8

Sweep

portion

remains the same

as

above.

Trigger

Holdoff

Variable: Increases A S'weep

holdoff

time

by

at least a

factor

of

10.

Delay

Time

Jitter:

1 part,

or

less, in 50,000 (0.002%)

of

10

times the A

TIME/DIV

switch

setting

.

Calibrated

Delay

Time

(VAR

control

to

CAL):

Continuous

from 0.2 ps to at least 5

seconds

after

the start

of A (delaying)

sweep.

x-v

X-Axis

Sensitivity

(X10

MAG

turned

off):

Same

as

the

vertical system.

X-Axis

Bandwidth: Dc

to at least 4

MHz, with

a

10

division

reference signal.

Phase

Difference

Between X-

and

V-Axis

Amplifiers:

Within

3° from

dc

to

50

kHz.

Deflection

Accuracy:

Within

4%.

CALIBRATOR

Output

Voltage: 0.3 V

within

1%

and

within

0.3%

from

+20°C

to

+30°C.

Output

Current:

30

mA

within

2%

from

+20

°C to

+30°C.

Repetition

Rate:

About

1 kHz.

64

475A/DM44

Operators

@

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Z AXIS

INPUT

Sensitivity:

Noticeable

intensity

modulation,

at

normal

intensity

settings,

by

a 5 V

p-p

signal. A positive-going

signal

decreases

intensity.

Frequency Range (Usable):

Dc

to

50 MHz.

Maximum

Input Voltage: 100 V

(dc

plus

peak ac)

or

100 V

p-p

ac

at 1 kHz

or

less.

OUTPUTS

CH

2 Out

Output

Voltage:

At

least50

mV/div

into

1 MO;

toat

least

25

mV/div

into

50

ohms.

Bandwidth:

Dc

to

at least 50

MHz

into

50

ohms.

DC

Level:

About

0 volts.

A+

and

B+

Gates

Output

Voltage:

About

5.5 V

of

positive-going

pulse.

Output

Resistance:

About

500

ohms.

AC POWER SOURCE

Regulating Ranges:

115

V

230 V

Low

99 V

to

121

V 198 V

to

242 V

Medium

104 V

to

126 V 207 V

to

253 V

High

108 V

to

132 V

216 V

to

264 V

Line Frequency:

From

48 Hz to 440 Hz.

Maximum Power Consumption:

100

watts

at 115

V,

60 Hz,

medium

range.

ENVIRONMENTAL

Operating Temperature:

-150 C

to

+550 C.

Operating

Altitude:

To

15,000 feet.

Maximum

operating

temperature

decreases

10 C/1 ,000 feet, above 5,000 feet.

Humidity (Operating and Storage): 5

cycles

(120

hours)

referenced

to

MIL-E-16400F.

@

475A/DM44

Operators

65

DM44

DIGITAL

MUL

TIMETER

I

RESISTANCE

1/TIME

Maximum Safe Input Voltage: 120 V rms

between

+ and

COM

inputs

.

Resistance Accuracy: 200 0

range-within

0.25%

±1

count,

plus

probe

resistance; 2 kO, 20 kO , 200 kO, and 2

MO

ranges-within

0.25%

±1

count;

20 MO

range-within

0.3% 1

count.

Temperature Dependence: 20 kO , 200 kO ar,d 2 MO

ranges-250

ppm/

oC;

2000,

2 kO and 20

MO

ranges-

350

ppm/

oC.

Resolution: 0.1

O.

Recycle Time:

At

least 3

measurements/second.

Response Time:

All

ranges

within 1 second

except

2

MO and 20 MO

(within 5 seconds).

TIME

Accuracy: + 15

to +35°C;

within

1%

of

reading

±1

count.

-15

to

+ 55° C;

within

1.5%

of

reading

±1

count.

Accuracy:

+15

to +

35°C;

within

2%

of

reading

±1

count.

-15

to

+55°C;

within

3%

of

reading

±1

count.

TEMPERATURE

Range:

-55°C

to

+150

° C in 1

range

.

Accuracy:

Original

Probe-Within

2°C, -55

°C

to

+125°C.

Within

3°C,

+125

°C to

+150

°C.

Replacement Probe:

Accuracy

will

equal

original

probe

accuracy

after

DM44

is

compensated

.

Maximum Safe Voltage

on

Measurement Surfaces:

±100

V (dc + peak ac)

above

chassis

ground.

Temperature (Storage and Operating):

Probe

Body

and

Cable,

-55

°C

to +105°C.

Probe

Sensor

Tip, -55°C

to

+150°C

.

DC

VOLTAGE

Maximum Safe Input Voltage:

±1200 V (dc

+ peak ac)

between

+ and chassis .

Common Floating Voltage:

±500

V (dc + peak ac)

to

chassis.

66 475A/DM44 Operators

REV. A,

DEC. 1977

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DC

Voltage Accuracy:

Within 0.1%

of

reading.

±1

count

.

Temperature Dependence: 44 ppmfO C.

Resolution: 100

tN.

Recycle Time:

At

least 3

measurements/second.

Response Time:

Within

0.5

second

.

Normal/Common

Mode Rejection Ratio:

Normal

Mode-At

least

60

dB

at

50

Hz

and 60 Hz.

Common

Mode-At

least 100

dB

at dc; 80

dB

at

50

Hz

and

60 Hz.

Input Impedance: 10 MO.

@

475A/DM44

Operators

67

ACCESSORIES

STANDARD ACCESSORIES

INCLUDED

2

10X

Probe

Packages 010-6106-03

Accessory

Pouch,

Snap

(w/o

OM)

016-0535-02

Accessory

Pouch

(OM) 016-0594-00

Accessory

Pouch,

Zipper

016-0537 -00

Operator's

Manual

070-2163-00

1 Service

Manual

(475A) 070-2162-00

2

Fuses, 1.5 A

3AG

fast-blow

159-0016-00

2

Fuses,

0.75 A

3AG

fast-blow

159-0042-00

Filter,

Blue

Plastic

(installed)

337 -167 4-00

CRT

Filter,

Clear

Plastic

337-1674-01

Adapter,

Ground

Wire

134-0016-01

Pair,

Test

Leads (OM)

003-0120-00

Service

Manual

(OM44)

070-2036-00

P6430

Temperature

Probe

(OM44)

010-6430-00

OPTIONAL ACCESSORIES

C-5A

Option 2 low

cost

fixed

focus

camera-Order

C-5A

Option

2.

Protective

Cover-Waterproof,

blue

vinyl-Order

016-

0554-00.

Folding

Polarized

Viewing

Hood-Order

016-0180-00.

Folding

Viewing

Hood,

light-shielding-Order

016-

0592-00.

Folding

Viewing

Hood,

light-occluding-Order

016-

0566-00.

Mesh

Filter-Improves

contrast

and

EMI

filter-Order

378-0726-01 .

SCOPE-MOBILE

Cart-Occupies

less

than

18

inches

aisle space, has

storage

area in

base-Order

200.

Test Lead

Set-1

black

lead

with

banana

plug

and

grounding

clip,

1 red lead

with

banana

plug

and

probe.

Includes

retractable

hook

tip

and CI tester

probe

cover.

May

be used with

other

miniature

probe

tip

accessories.

Order

012-0427-00.

68

475A/OM44 Operators

REV

A.

SEPT

1978

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OPTIONS

Your

instrument

may

contain

the

following

options

:

OPTION

1

Deletes the

temperature

probe

from

the DM 44.

OPTION

4

The

instrument

is

modified

to meet certain

specifications

on radiated

interference

requirements

.

There is

no

change

in

operating

instructions.

OPTION

7

At the time of this

writing,

instruments

having the DM44

do

not

have the

Option

7 available.

Option 7 permits

operation

on

12

or

24

Vdc

with

no

performance

deterioration. Circuitry

is

provided

to

protect

against

damage

due

to

connection

of

24 V when

in the

12 V mode

of

operation. The

24-volt external

input

permits

use

with

conventional

dc

power

(marine and aircraft).

@

475A/DM44 Operators

69

•

•

•

•

•

Tektronix.

tnc

092380

This

Insert

Is

provided

as

a

supplement

to

the

Instruction

manual

furnished

with

this

modified

Instrument.

The

Information

given

In

this

Insert

supersedes

that

given

In

the

manual.

This

insert

material

Copyright

©

1980

by

Tektronix,

Inc.,

Beaverton,

Oregon.

Printed

in

the

United

States

01

America.

All

rights

reserved.

Contents

of

this

insert

may

not

be

reproduced

In

any

form

without

permission

01

the

copyright

owner.

• P. O.

Box

500

•

Beaverton,

Oregon

97077

MODIFICATION

INSERT

475A/DM44

MOD

PC

Phone

644-0161 • Cables:

Tektronix

061-2422-00

•

•

•

•

•

•

•

•

475A/DM44

MOD

PG

This

manual

insert

describes

MOD

PG

as

it

applies

to

the

TEKTRONIX

475A/DM44

Oscilloscope.

The

Delay

time

and

Calibrator

frequency

tolerances

are

reduced,

a

front-panel

light

is

added

adjacent

to

the A TRIGGER

HOLDOFF

control

to

indi-

cate

when

the

control

is

out

of

the

(detent)

Norm

position,

and

the

electrical

length

of

the

vertical

amplifier

delay

line

is

increased.

A

special

probe

package

and

viewing

hood

are

added

to

the

standard

accessories

complement.

The

legend

"Property

of"

and

the

IBM

logotype

are

added

to

the

475A

front

panel,

and

an

IBM

"F

& F"

(serial)

number

is

added

to

the

rear

panel.

A

modi-

fied

DM44

Digital

Multimeter

with

added

INDEPENDENT/TRACKING

mode

selection

with

timing

compensation

is

added.

Differential

Delay

Accuracy.

ccuracy

of

differential

time

measurements

(TIME

or

l/TIME mode)

using

the

DELAY

TIME

POSITION

and

~Tn1E

controls

will

be

accu-

rate

within

0.75%

of

the

reading

±1

count

for

measurements

between

points

0.5

to

10

divisions

(except

at

0.2

through

0.5

~s/div,

1.0

to

10

divisions)

from

the

start

of

the

A Sweep

trace

for

sweeps

faster

than

0.5

s/div,

over

the

000

0 0 0

temperature

range

+15

to

+32 C

(60

to

90

F).

Over

the

+15 C

to

+55 C

temperature

range,

standard

475A

performance

limits

apply.

INDEPENDENT/TRACKING

Modes. The

two-position

toggle

switch

added

in

the

DM44

front

panel

functions

only

in

the

TIME

and I/TIME modes

to

permit

independent

intensified

zone

adjustment

with

fine

time

zero

compensation

between

vertical

channels

as

follows:

1

of

5

47SA/DM44

MOD

PG

Tracking.

With

the

added

switch

in

the

TRACKING

position,

the

time

measurement

circuits

function

as

for

the

standard

DM44,

with

the

DELAY

TIME

POSITION

control

moving

both

intensified

zones.

Independent.

With

the

added

switch

in

the

INDEPENDENT

position,

the

DELAY

TIME

POSITION and

~TIME

controls

position

their

respective

intensified

zones

independently,

and

the

TIME

(or

l/TIME)

readout

is

adjustable

over

a

small

range

by

the

added

side-panel

ZERO

ADJ

screwdriver

control,

to

permit

compensation

for

small

Ch

l/Ch 2 probe

and

admplifier

transit-time

differences.

ZERO

ADJ

Procedure.

To

set

the

ZERO

ADJ

to

compensate

for

vertical

chan-

nel

transit

time

differences,

set

the

controls

as

follows:

47SA

A

SOURCE

CH

1

VERT

MODE

ALT

HORIZ

DISPLAY

A

INT

B

SOURCE

STARTS

AFTER

DELAY

VAR

TIME/DIV

Detent

position

DM44

FUNCTION

TIME

MODE

INDEPENDENT

2

of

5

L

.--

L

.-

•

•

...

.-

L

.-

L.

r

L

r

•

•

475A/DM44

MOD

PG

Connect

Ch

1 and

Ch 2 vertical

input

probes

to

the

same

signal

source

--

such

as a fast

risetime

pulse

generator

with a repetition

rate

of

at

least

1

MHz.

Set

A TIME/DIV

to

display

several

pulses

on

the

crt

(see

Fig.

1).

INTENSIFIED

ZONE

Fig.

1

Set

B TIME/DIV

several

positions

more

clockwise

than

A TIME/DIV.

Adjust

the

DELAY

TIME

POSITION

control

so

that

an

intensified

zone

occurs

on

the

leading

edge

of a pulse

between

the

1st

and

the

9th

horizontal

graticule

position.

3

of

5

475A/DM44

MOD

PG

Adjust

the

~TIME

control

so

that

the

second

intensified

zone

is

positioned

over

the

same

leading

edge

as

the

first

intensified

zone.

Set

the

HORIZ

DISPLAY

switch

to

B DLy'D.

Slightly

readjust

the

DELAY

TIME

POSI-

TION

and

ATIME

controls

to

superimpose

the

waveforms

(see

Fig.

2).

(B

TIME/DIV

may

be

reduced

for

better

time

difference

resolution.)

SUPERIMPOSE

LEADING

EDGES

Fig.

2

4

of

5

CH

1

\

'I

.....

~

CH

2

<j

L

.-

L

r

--

•

•

iI

L

..

•

•

•

iF

L

.-

•

•

•

•

475A/DM44

MOD

PG

When

the

leading

edges

of

the

same

pulse

are

exactly

superimposed,

the

DM44

display

should

indicate

0000.

If

it

does

not,

adjust

the

ZERO

ADJ

control

with a small

screwdriver

so

that

the

display

reads

0000.

The

system

is

now

compensated

for

small

time

differences

between

the

two

input

channels.

Measurements

such

as

those

described

in

the

47sA/DM44

Operators

manual

may

be

taken

directly

from

the

DM44

display

without

hav-

ing

to

perform

the

algebraic

addition

of

the

transit-time

difference.

Transit

Time

Compensation.

Transit

time

correction

range

of

the

ZERO

ADJ

con-

trol

when

the

DM44

is

set

for

TIME

or

l/TIME

and

the

added

front-panel

switch

is

set

for

INDEPENDENT

corrects

for

internal

Ch

l/Ch 2 transit-time

difference,

plus

the

following

additional

range

to

accommodate

probe

transit-time

dif-

ferences:

A TIME/DIV

.05

~s

to

0.2

~s/div

.5

~s

to

2

~s/div

5

~s

to

20

~s

div

Effective

ZERO

ADJ

Range

±300

ps

±3

ns

±30

ns

The

ZERO

ADJ

adds a fixed

numerical

correction

to

the

digital

readout

for

each

decade

TIME/DIV

range.

The

absolute

time

correction

is

valid

only

for

one

TIME/DIV

decade.

Use

at

sweeps

slower

than

2

~s/div

is

not

recommended.

5

of

5