Tektronix 47e5a User manual

I

II . 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

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.

I

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

17

18

19

20

22

24

27

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

Ii 475A1DM44 Operators @

I

I TABLE OF

CONTENTS

(cont)

I

DM44

DELAYED

OR

MIXED

SWEEP

TIME

Page

OPERATOR

'S

SPECIFICATIONS

(cont)

Page

MEASUREMENTS

54

I

TIME

DIFFERENCE

BETWEEN REPETITIVE Z

AXIS

INPUT

65

PULSES

(DM44)

56

OUTPUTS

65

TIME

DURATION

MEASUREMENTS

(DM44)

57

AC

POWER

SOURCE

65

I

FREQUENCY

MEASUREMENTS

(DM44) 58

ENVIRONMENTAL

65

TIME

DIFFERENCE

BETWEEN

TWO

PULSES DM44

DIGITAL

MULTIMETER

66

FROM

DIFFERENT

SOURCES

(DM44) 58

RESISTANCE

66

I

RISETIME

(DM44)

60

TIME

66

MIX

(DM44)

61

1/TIME

66

TEMPERATURE

66

OPERATOR'S

SPECIFICATIONS

62

DC

VOLTAGE

66

I 475A

OSCILLOSCOPE

62

VERTICAL

62

TRIGGERING

63

ACCESSORIES

68

I

DIFFERENTIAL

TIME

MEASUREMENT

STANDARD

ACCESSORIES

68

(BASIC

475A)

63

OPTIONAL

ACCESSORIES

68

DIFFERENTIAL

TIME

MEASUREMENT

I

(DM44)

64

HORIZONTAL

64

OPTIONS

69

X-Y 64

OPTION

4 69

I

CALIBRATOR

64

OPTION

7 69

@

475A/DM44

Operators

ill

LIST OF ILLUSTRATIONS I

Page Page I

Fig.

1.

Regulating

range

selector

and

line

Fig. 17.

Common-mode

rejection. 36

fuse. 3 Fig. 18.

Time

duration.

38 I

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 I

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 I

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

I

@

iv

475A/DM44

Operators

I LIST OF TABLES

I Page Page

TABLE

1

Regulating

Ranges 2

TABLE

4

Centigrade

to Fahrenheit

Conversion

26

I

TABLE

2 Resistance Ranges

20

TABLE

5 DM44 Delayed Sweep

Displays

54

TABLE

3 Volts Ranges

22

I

I @

475A/DM44

Operators v

475A

Oscilloscope

with

DM44

Digital

Multimeter.

475A1DM44 Operators @

I

I·

I'

I

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

linefuse

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 475A/DM44 Operators @

I

I @

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 least25 volts

per

division

(10 volt

position).

4.

UNCAL

Lamp-Indicates

when

the

VAR

VOLTS/OIV

control

is

out

of

the

calibrated

detent

and the

vertical

deflection

factor

is

uncalibrated

.

475A/DM44

Operators

@

I

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

vert

i

cal

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

appr

o

ximately

250 kHz.

Useful

at

sweep

rates

slower

than

about

50

micr

o

seconds/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 @

I

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

cont

r

ol

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 5ranges

(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

Fa

c

tor

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

procedur

e

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

.

475A/DM44

Operators @

I

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

externaI

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

10

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.

I

475A/OM44

Operators @ I

I

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

(muItiple

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 usefuI

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).

12

47SA/DM44

Operators

@

I

Tektronix 47E5A User manual

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