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INSTRUCTION

MIAN

UAL

TYPE

3177

SAMPLING

SWEEP

UNIT

Tektronix,

Inc.

S.W,

Millikan

Way

@

P.O.Box

500

@

Beaverton,

Oregon

@

Phone

MI

4-0161

@

Cables:

Tektronix

070-333

763

Type

3177

WARRANTY

All

Tektronix

instruments

are

warranted

against

defective

materials

and

workman-

ship

for

one

year.

Tektronix

transformers,

manufactured

in

our

own

plant,

are

war-

ranted

for

the

life

of

the

instrument.

Any

questions

with

respect

to

the

war-

ranty

mentioned

above

should

be

taken

up

with

your

Tektronix

Field

Engineer.

Tektronix

repair

and

replacement-part

service

is

geared

directly

to

the

field,

there-

fore

all

requests

for

repairs

and

replace-

ment

parts

should

be

directed

to

the

Tek-

tronix

Field

Office

or

Representative

in

your

area,

This

procedure

will

assure

you

the

fastest

possible

service.

Please

include

the

instrument

Type

and

Serial

number

with

all

requests

for

parts

or

service.

Specifications

and

price

change

priv-

ileges

reserved.

Copyright

©)

1963

by

Tektronix,

Inc.,

Beaverton,

Oregon.

Printed

in

the

United

States

of

America.

All

rights

reserved.

Contents

of

this

publication

may

not

be

re-

produced

in

any

form

without

permission

of

the

copyright

owner.

http://manoman.sghill.com

Type

3177

TYPE

3777

SAMPLING

SWEEP

nes

VARIABLE

SITION

TIME/DIV.

oO

ADJ

5

uSEC

2

1

HORIZ.

DOTS

UNCAI

MAG

PER

DIV,

@

x10

é

TRIGGER

ee

=

sensiriviry

|

MANUAL

SCAN

OR

EXT

ATTEN,

SWEEP

MODE

NORMAL

pds

han

MANUAL

RECOVERY

TIME

SINGLE

DISPLAY

RESET

SWEEP

OUTPUT

™’

iv,

OV

(10

KA)

The

Type

3T77

Sampling

Sweep

Unit.

SECTION

1

CHARACTERISTICS

General

Information

The

Type

3177

Sampling

Sweep

Plug-In

Unit

is

designed

for

use

with

all

Tektronix

Type

560-Series

Oscilloscopes

except

the

Type

560

and

Type

565.

The

Type

3177

is

equipped

to

drive

a

digital

unit

in

the

Type

567

Readout

Oscilloscope.

The

Type

3177

must

be

inserted

into the

right-hand

plug-

in

compartment

of

the

oscilloscope

and

a

vertical

sampling

plug-in

unit

(such

as

the

Type

3876)

must

be

inserted

into

the

left-hand

plug-in

compartment

to

complete

the

composite

sampling

system.

Equivalent

Sweep

Rates

Variable

in

fifteen

steps

from

0.2

nsec/div

to

10

usec/div

(0.02

nsec/div

to

1

«sec/div

with

HORIZ.

MAG.

switch

at

X10).

Accuracy

typically

within

1%,

and

in

all

cases

within

3%

of

the

indicated

sweep

rate

with

HORIZ.

MAG.

switch

at

X1.

With

HORIZ.

MAG.

switch

at

X10,

accuracy

is

within

5%.

The

sweep

rate

at

any

given

setting

of

the

TIME/DIV.

switch

can

be

increased

by

about

3

times

with

the

VARIABLE

control.

Samples

Per

Division

10/div

or

100/div.

External

Triggering

Pulse

Repetition

Rate:

Up

to

3

&

10°

pulses/second

(300

megacycles}.

Trigger

circuitry

counts

down

to

a

maximum

sampling

rate

of

about

100

kilocycles/second.

Minimum

Pulse

Amplitude

and

Width:

10

millivolts,

peak-

to-peak,

with

at

least

a

2-nanosecond

width.

With

larger

pulse

amplitudes

(up

to

800

millivolts)

minimum

pulse

width

decreases.

Overload

damage

occurs

at

5

volts

and

above.

Sinusoidal

Frequency

Range:

100

kilocycles

to

300

mega-

cycles;

10

to

800

millivolts

amplitude.

Low

Frequency

Response

(to

trigger

pulses}:

300

kilo-

cycles

(3-db

down

point).

Jitter:

50

picoseconds

or

0.001%

fast

ramp

duration,

whichever

is

greater

(for

50-millivolt

amplitude,

2-nano-

second

width

pulses

with

a

repetition

rate

less

than

10

megacycles},

Jitter

increases

as

pulse

amplitude

and/or

width

decreases

when

repetition

rates

exceed

10

mega-

cycles.

Internal

Triggering

Same

characteristics

as

External

Triggering

but

modified

by

vertical

plug-in

unit

used.

When

used

with

the

Type

3876,

all

characteristics

are

the

same

except

five

times

more

amplitude

is

required

at

the

Type

3876

INPUT

A

or

INPUT

B

connectors

and

the

low-frequency

response

is

3-db

down

at

450

kilocycles.

External

Sweep

Input

Sensitivity:

Adjustable

from

5

to

25

volts

per

horizontal

division

(50

volts

required

for

a

full

10-division

display,

250

volts

maximum).

Input

Resistance:

28

to

100

kilohms,

depending

on

setting

of

EXT.

ATTEN.

control.

Sweep

Output

Amplitude:

1

volt/div

from

a

source

impedance

of

10

kilohms.

Delay

Variable

through

100

nsec.

Mechanical

Construction:

Aluminum

alloy

chassis.

Finish:

Photo-etched,

anodized

front

panel.

Weight:

5

pounds.

Accessories

Supplied

With

the

Type

3177

Tektronix

Part

Number

2

500,

10-nsec

cables

(017-501)

RG-58/AU

with

General

Radio

connectors.

1

Adapter,

BNC-to-GR

(017-025)

1

Adapter,

male

BNC-to-female

(103-032)

UHF

2

Attenuators,

1OXT,

509

with

(017-044)

GR

connectors

2

Instruction

manuals

(070-333}

1-1

Operating

Instructions

—

Type

3177

f

TYPE

31777

SAMPLING

SWEEP

VARIABLE

Beet

eye

TIME/DIV.

GAIN

ADJ.

5

nSEC

2

1

HORIZ.

DOTS

UNCAL

MAG.

PER

DIV.

.

2

@

X10

|

10

7—-

TRIGGERS

SENSITIVITY

x1

MANUAL

SCAN

OR

EXT.

ATTEN.

SWEEP

MODE

MANUAL NORMAL

=

100

nSEc

RECOVERY

TIME

SINGLE

DISPLAY

]

RESET

/

=

y

_

+

EXT.

@

‘)

SWEEP

SWEEP

~

j

INPUT

OUTPUT

iv/DIV.

(10

Kn)

:

.

j

J

SERIAL

7

'

TEKTRONIX.

INC.

PORTLAND,

OREGON,

U.S.A.

Fig.

2-1.

Front

panel

of

the

Type

3177.

2-0

SECTION

2

OPERATING

INSTRUCTIONS

Introduction

The

Type

3177

Sampling

Sweep

Plug-In

Unit

(with

a

ver-

tical

sampling

plug-in

unit)

equips

any

Type

561A,

RM561A,

564, 567,

or

RM567

Oscilloscope

for

sampling-type

opera-

tion.

Front-panel

operation

of

the

Type

3177

resembles

that

of

non-sampling

(real

time}

time-base

units.

This

section

of

the

manual

covers

the

operation

of

the

front-pane!l

controls

and

connectors

(see

Fig.

2-1).

Function

of

Front-Panel

Controls

and

Connectors

POSITION

Conirol

Positions

the

display

horizontally.

HORIZ.

MAG.

Switch

Selects

X1

or

X10

horizontal

display

magnification.

DOTS

PER

DIV.

Switch

Selects

either

10

or

100

samples

per

division.

SWEEP

MODE

Switch

NORMAL

position:

Permits

automatic

dot-by-dot

advance-

ment

through

the

oscilloscope

display.

SINGLE

DISPLAY

position:

Permits

one

display

after

the

RESET

button

is

pressed.

(Useful

for

photographing

the

display.)

-++EXT.

SWEEP

INPUT

position:

Permits

control

of

the

scanning

function

with

an

external

voltage.

MANUAL

position:

Permits

manual

dot-by-dot

advance-

ment

through

the

display

by

turning

the

MANUAL

SCAN

control.

(For

recorder

applications.)

MANUAL

SCAN

OR

EXT.

ATTEN.

Control

Provides

an

internal

semi-intergated,

variable

voltage

for

scanning

when

the

SWEEP

MODE

switch

is

in

the

MANUAL

position,

and

serves

as

a

variable

attenuator

when

the

SWEEP

MODE

switch

is

in

the

+EXT.

SWEEP

INPUT

position.

+EXT.

SWEEP

INPUT

Connector

For

applying

an

external

scanning

voltage.

Sensitivity

variable

from

5

to

25

volts/div;

input

impedance

variable

from

28

to

100

kilohms.

Maximum

input

voltage

250

volts,

peak.

SWEEP

OUTPUT

Connector

For

monitoring

the

sweep

voltage.

(Output

variable

trom

about

3.5vde

to

about

15

vde;

I-volt

change

equals

1

division

of

horizontal

deflection

with

10-kilohm

source

impedance.)

TRIG.

OUT

Connector

For

externally

monitoring

a

positive

trigger

pulse

after

each

trigger

event.

The

pulse

width

is

at

least

0.4

micro-

second

at

0.15-volt

amplitude.

®

EXT.

INPUT

Connector

For

applying

an

external

trigger.

Input

impedance:

50

ohms

shunted

by

12

microhenries.

INT.-EXT.

Switch

Selects

either

an

internal

trigger

(INT.

position)

from

the

vertical

plug-in

unit,

or

an

external

trigger

(EXT.

position)

from

the

EXT.

INPUT

connector,

and

determines

whether

triggering

takes

place

on

the

positive

(+)

or

negative

(—)

slope

of

the

input

signal.

DELAY

Control

Allows

the

start

of

the

display

to

be

varied

through

100

nanoseconds

with

respect

to

the

trigger

event.

TRIGGER

SENSITIVITY

Control

Varies

the

sensitivity

of

the

triggering

circuit.

Also

causes

the

trigger

circuit

to

free-run

when

turned

fully

clockwise.

RECOVERY

TIME

Control

Varies

the

holdoff

time

of

the

trigger

circuits

to

assure

stable

triggering.

TIME/DIV.

Switch

Sets

the

equivalent

sweep

rate

of

the

display.

VARIABLE

Control

Varies

the

sweep

rate

(uncalibrated)

between

TIME/DIV.

steps.

The

equivalent

sweep

rate

at

any

given

setting

of

the

TIME/DIV.

switch

can

be

increased

about

3

times.

GAIN

ADJ.

(a

front-panel

screwdriver

adjustment)

Adjusts

gain

to

match

oscilloscope

deflection

factor.

Installing

the

Type

3177

into

the

Oscilloscope

CAUTION

Turn

off

oscilloscope

power

while

inserting

or

removing

plug-in

units.

Otherwise,

power

supplies

in

the

oscilloscope

may

fail

to

regulate

momen-

tarily

as

plug-in

units

are

removed

or

replaced.

The

Type

3177

is

designed

to

drive

the

horizontal

de-

flection

plates

of

the

crt;

it

must

be

used

in

the

right-hand

plug-in

compartment.

When

inserting

the

Type

3177

into

the

plug-in

compartment,

first

check

that

the

latch

at

the

bottom

of

the

front

panel

is

in

a

horizontal

position.

Then

make

sure

the

interconnecting

plugs

are

properly

aligned.

The

Type

3177

should

then

slip

easily

into

the

compartment.

Once

the

plug-in

has

been

properly

seated,

turn

the

aluminum

knob

of

the

plug-in

unit

a

few

turns

clockwise

until

it

is

hand-tight.

To

remove

the

plug-in

unit,

turn

the

aluminum

knob

counterclockwise

as

far

as

it

will

go

and

pull

the

plug-in

unit

straight

out.

2-1

Operating

Instructions

—

Type

3177

Displaying

a

Signal

The

following

procedure

covers

first-time

operation

of

the

Type

3177.

It

will

enable

you

to

display

a

signal

on

the

ert.

Use

this

procedure

in

conjunction

with

the

vertical

plug-in

unit

instructions.

1.

Set

the

Type

3777

front-panel

controls

as

follows:

POSITION

Midrange

TIME/DIV.

5

nSEC

VARIABLE

CALIB.

DELAY

Fully

counterclockwise

TRIGGER

SENSITIVITY

Fully

counterclockwise

HORIZ.

MAG.

Xl

DOTS

PER

DIV.

100

SWEEP

MODE

NORMAL

INT.-EXT.

INT.

{Set

to

polarity

of

signal

you

wish

to

observe)

RECOVERY

TIME

2.

Insert

the

Type

3177

into

the

right-hand

plug-in

com-

partment

of

the

oscilloscope

and

the

vertical

sampling

plug-

in

unit

into

the

left-hand

compartment.

Turn

on

the

oscillo-

scope

power

and

allow

a

few

minutes

for

warm-up.

Fully

counterclockwise

3.

Apply

the

signal

you

wish

to

observe

to

the

input

connector

of

the

vertical

sampling

plug-in

unit.

(Note:

Make

sure

the

signal

meets

the

triggering

requirements

described

in

Section

1.}

4.

Slowly

advance

the

TRIGGER

SENSITIVITY

control

for

a

stable

display.

The

RECOVERY

TIME

control

may

also

help

stabilize

the

display.

5.

Set

the

TIME/DIV.

switch

to

the

position

where

the

displayed

signal

covers

the

desired

amount

of

horizontal

graticule

divisions.

6.

With

the

POSITION

control,

move

the

display

hori-

zontally

to

the

desired

point

on

the

graticule.

7.

Turn

the

DELAY

control

and

notice

its

effect

on

the

display.

The

action

of

the

DELAY

control

is

most

significant

at

faster

sweep

rates.

The

DELAY

control

varies

the

position

of

the

displayed

pulse

with

respect

to

the

start

of

the

trace.

The

position

of

the

pulse

with

respect

to

the

start

of

the

trace

can

be

varied

100

nanoseconds

with

the

DELAY

control.

8.

Set

the

SWEEP

MODE

switch

to

MANUAL

and

turn

the

MANUAL

SCAN

control.

Note

the

horizontal

scanning

of

the

electron

beam

on

the

crt.

9.

Set the

SWEEP

MODE

switch

to

SINGLE

DISPLAY.

Press

the

RESET

button.

After

pressing

the

RESET

button,

the

Type

3177

allows

one

complete

scan

of

the

electron

beam

across

the

crt.

This

is

particularly

useful

for

photo-

graphing

displays

at

slow

pulse

repetition

rates.

Gain

Adjust

The

basic

oscilloscope

crt

deflection

factor

varies

slightly

from

one

oscilloscope

to

another.

For

this

reason,

the

GAIN

ADJ.

(a

front-panel

screwdriver

adjustment)

should

be

checked

and

adjusted

as

necessary

each

time

the

Type

3177

is

used

in

a

different

oscilloscope.

Also,

check

the

2-2

GAIN

ADJ.

occasionally

during

regular

use

of

the

instru-

ment.

Checking

or

setting

the

GAIN

ADJ.

requires

the use

of

an

accurate

frequency

source,

such

as

the

Tektronix

Type

180A

Time-Mark

Generator.

The

frequency

standard

used

must

have

a

frequency

output

of

at

least

100

kilocycles,

and

preferably

above

1

megacycle.

To

check

or

adjust

the

Type

3T77

GAIN

ADJ.

control,

proceed

as

follows:

1.

Insert

the

Type

3T77 and

the

associated

vertical

sampling

plug-in

unit into

the

oscilloscope,

turn

on

the

power

and

allow

the

instrument

to

warm

up

for

at

least

2

minutes

before

proceeding.

2.

Set

the

front-panel

controls

of

the

Type

3177

as

follows:

POSITION

Midrange

DOTS

PER

DIV.

100

TRIGGER

SENSITIVITY

Fully

clockwise

VARIABLE

CALIB.

SWEEP

MODE

NORMAL

HORIZ.

MAG.

X]

INT.-EXT.

+

INT.

Other

controls

may

be

set

to

any

position.

3.

From

an

accurate

frequency

source,

apply

a

signal

to

the

Input

connector

of

the

vertical

sampling

plug-in

unit

and

adjust

for

a

vertical

deflection

of

2

to

6

divisions.

4.

Determine

the

time

duration

of

one

cycle

of

the

signal

from

the

frequency

source

{time

duration

of

one

cycle

(in

seconds)

is

the

reciprocal

of

the

frequency

{in

cycles

per

second)

).

5.

Set

the

TIME/DIV.

switch

for

a

sweep

rate

that

will

display

one-half

to

one

cycle

of

the

applied

signal

per

division

of

deflection.

6.

Set

the

TRIGGER

SENSITIVITY

and

RECOVERY

TIME

controls

for

a

stable

display.

7.

Check

for

the

proper

number

of

cycles

per

division.

If

the

number

of

cycles

per

division

does

not

exactly

agree

with

the

setting

of

the

TIME/DIV.

switch,

set

the

GAIN

ADJ.

for

the

proper

timing.

Use

the

POSITION

control

to

align

the

display

with

the

graticule

markings.

Triggering

the

Type

3177

The

Type

3T77

can

be

triggered

either

internally

or

externally.

Internal

triggering

requires

no

signal

connections

to

the

Type

3777

since

the

triggering

signal

is

coupled

internally

from

the

vertical

sampling

plug-in

unit.

However,

external

triggering

is

more

sensitive

(see

Section

1).

External

triggering

is

also

independent

of

the

displayed

waveform.

Thus,

when

signals

of

different

amplitudes

are

applied

to

the

vertical

plug-in

unit,

the

triggering

controls

do

not

require

resetting

for

a

stable

display.

However,

an

external

triggering

signal

must

be

related

in

time

to

the

displayed

signal

to

maintain

stable

triggering.

The

+

and

—

positions

of

the

INT.-EXT.

switch

determine

whether

triggering

takes

place

on

the

positive-

or

negative-

@l

going

slope

of

the

triggering

signal.

The

INT.

or

EXT.

posi-

tions

determine

whether

the

triggering

signal

comes

from

the

vertical

sampling

plug-in

unit

or

from

the

EXT.

INPUT

connector.

Selecting

the

Equivalent

Sweep

Rate

The

Type

31777

TIME/DIV.

switch

selects

equivalent

sweep

rates

from

0.2

nanosecond

per

division

to

10

micoseconds

per

division.

These

rates,

in

turn,

provide

an

equivalent

10-

division

display

width

from

2

nanoseconds

to

100

micro-

seconds.

Setting

the

HORIZ.

MAG.

switch

to

X10 increases

the

equivalent

sweep

rate

10

times

at

any

setting

of

the

TIME/DIV.

switch.

This

expands

the

display

in

both

direc-

tions

from

the

center

graticule

division

to

cover

the

entire

graticule

(horizontally).

The

VARIABLE

control

increases

the

equivalent

sweep

rate

at

any

setting

of

the

TIME/DIV.

switch

about

3

times

(uncalibrated)

when

the

control

is

fully

clockwise.

Selection

of

sweep

rate

depends

on

the

duration

of

the

applied

signal

and

the

specific

portion

of

the

signal

you

wish

to

observe.

The

DELAY

control

aids

in

observing

a

specific

portion

of

the

applied

signal.

The

equivalent

sweep

rates

of

the

Type

3777

are

accurate

within

3%

of

the

TIME/DIV.

control

setting

when

the

VARI-

ABLE

control

is

set

to

CALIB.

and

the

HORIZ.

MAG.

switch

is

set

to

X1.

This

permits

accurate

time

measurements

di-

rectly

from

the

oscilloscope

display.

Selecting

the

Dots

Per

Division

In

a

sampling

system,

the

applied

signal

is

displayed

as

a

series

of

dots

distributed

across

the

ert.

With

a

greater

number

of

dots

in

the

display,

the

trace

appears

more

con-

tinuous.

With

less

dots

in

the

display,

there

is

less

continu-

ity

in

the

trace

and

the

individual

dots

become

more

apparent

(see

Fig.

2-2).

The

DOTS

PER

DIV.

switch

selects

either

10

dots

per

division

or

100

dots

per

division.

Proper

setting

of

the

DOTS

PER

DIV.

switch

is

a

choice

between

good

trace

continuity

and

flicker.

Flicker

will

become

ap-

parent

with

signals

of

low

repetition

rate

when

the

DOTS

PER

DIV.

switch

is

set

to

100.

By

changing

the

setting

of

the

DOTS

PER

DIV.

switch

to

10,

flicker

will

become

less

apparent.

However,

with

10

dots

per

division,

make

sure

the

SMOOTH-NORMAL

switch

of

the

vertical

sampling

plug-in

unit

is

set

to

NORMAL.

Otherwise,

the

display

may

be

distorted.

Signals

with

fast

repetition

rates

cause

less

flicker;

thus

the

DOTS

PER

DIV.

switch

may

be

set

to

100

for

best

trace

continuity.

When

making

time

measurements

from

the

crt,

the

indi-

vidual

dots

can

serve

as

time

markers.

For

example,

suppose

the

Type

3177

TIME/DIV.

switch

is

set

to

1

nSEC

and

the

DOTS

PER

DIV.

switch

is

set

to

10.

In

this

case,

each

dot

@i

Operating

Instructions

——

Type

3177

4

+

+

*e,

*,

+

.

>

.

.

*

+

.

,

ji

aa

.

eee eee

SSS

ES

SESS

SS

SSSR

SEER

SER

SESE

Eee

eee

TrvTyrrer

TT

Tere

Rrergrrre

TUT

TTT

rTrTrypserre

. .

7

hal

.

+

. :

>

°:

‘

es

y

os

ere

een'

(a)

=

TIT

TTT

Tyr

tt

SEE

Ree

SaaS

ea

eeee

TTT

+

tipi

THT

+

a:

a

+

N

arn

nenie

A

\

4)

(b)

Fig,

2-2.

(a)

A

typical

display

with

the

DOTS

PER

DIV.

switch

set

to

10.

(b)

The

same

signal

with

the

DOTS

PER

DIV.

switch

set

to

100.

represents

0.1

nanosecond

in

equivalent

time

(1

nanosecond

per

division

divided

by

the

10

dots

per

division).

This

application

is

easiest

when

the

display

contains

10

dots

per

division

(i.e.,

the

DOTS

PER

DIV.

switch

must

be

set

to

10

or

the

HORIZ.

MAG.

switch

must

be

set

to

X10).

Under

certain

conditions

it

is

possible

to

get

a

false

display

when

using

a

sampling-type

system.

This

happens

when

certain

relationships

exist

between

the

frequency

of

the

applied

signal

and

the

equivalent

time

between

dots.

A

false

display

can

be

detected

by

changing

the

setting

of

the

DOTS

PER

DIV.

switch

or

the

TIME/DIV.

switch.

With

a

valid

display,

a

change

in

the

equivalent

time

between

dots

should

not

affect

the

displayed

waveform.

However,

if

the

display

is

false,

it

will

change

in

apparent

repetition

rate

or

disappear

when

the

equivalent

time

per

dot

changes.

2-3

SECTION

3

APPLICATIONS

The

procedures

in

this

section

describe

some

basic

applications

for

the

Type

3177.

Time

and

Frequency

Measurements

The

Type

3177

is

accurately

calibrated

to

indicate

equiva-

lent

time

per

division

along

the

horizontal

axis

of

the

oscilloscope

display.

Thus,

the

following

procedures

concern

measuring

time

and

frequency

of

electrical

events.

Time

Duration.

To

measure

the

time

duration

of

an

electrical

event,

proceed

as

follows:

1.

Obtain

a

stable

display

of

the

event

you

wish

to

measure.

2.

Set

the

TIME/DIV.

switch

so

the

distance

between

the

two

points

you

wish

to

measure

covers

a

large

portion

of

the

graticule.

3.

To

get

the

time

duration,

count

the

number

of

grati-

cule

divisions

between

the

two

points,

multiply

by

the

TIME/

DIV.

switch

setting,

then

divide

the

result

by

the

HORIZ.

MAG.

switch

setting.

To

illustrate

this

procedure,

assume

the

TIME/DIV.

switch

is

set

to

5nSEC

and

the

HORIZ.

MAG.

switch

to

X1.

Then,

assume

the

distance

between

the

two

points

on

the

display

is

4.8

major

graticule

divisions.

Thus,

the

time

duration

would

be

4.8

divisions

multiplied

by

5

nanoseconds/divi-

sion

(TIME/DIV.

switch

setting),

or

24

nanoseconds,

Risetime.

The

risetime

of

a

pulse

is,

by

definition,

the

time

required

for

the

pulse

to

rise

from

10%

to

90%

of

2.2

div.

or

.44

nsec

—

!

"TT

90%

f

point

TTTETT

TTT

TAT

TY

Ty

10%

point

+t

ttt

HH

i

Pitisi

ris

tig

4

4+

tt

4+

+

+

.2

nsec/div.

Fig.

3-1.

Determining

pulse

risetime.

®

its

maximum

amplitude.

To

measure

pulse

risetime

or

fall-

time

proceed

as

follows:

1.

Set

the

TIME/DIV.

switch

and

the

DELAY

control

to

display

the

leading

edge

of

the

pulse.

(Or,

for

falltime

measurement,

display

the

falling

edge.)

For

best

accuracy,

the

rising

portion

of

the

pulse

should

span

at

last

two

horizontal

graticule

divisions.

2.

Set

the

vertical

plug-in

unit

so

the

display

covers

two

to

eight

vertical

graticule

divisions.

3.

Measure

the

horizontal

distance

between

the

10%

and

90%

amplitude

points

on

the

waveform.

See

Fig.

3-1.

4.

The

risetime

is

the

number

of

divisions

in

step

3

multi-

plied

by

the

setting

of

the

TIME/DIV.

switch

(divided

by

the

HORIZ.

MAG.

switch

setting).

Frequency

or

Repetition

Rate.

Frequency

or

repetition

rate

is

the

number

of

complete

electrical

events

occurring

in

a

second.

To

measure

the

frequency

or

repetition

rate

of

the

displayed

signal

in

cycles

(or

pulses}

per

second,

pro-

ceed

as

follows:

1.

Find

the

time

duration

of

a

complete

event

as

described

under

‘Time

Duration’.

2.

The

frequency

or

repetition

rate

of

the

applied

signal

is

the

reciprocal

of

step

1.

To

illustrate

this

procedure,

assume

the

TIME/DIV.

switch

is

set

to

20nSEC

and

the

HORIZ.

MAG.

switch

to

X10.

Then,

assume

one

event

covers

6.4

major

graticule

divisions.

Thus,

the

frequency

or

repetition

rate

would

be

6.4

divisions

multiplied

by

20

nanoseconds/division

(TIME/DIV.

switch

setting)

divided

by

10

{the

HORIZ.

MAG.

switch

setting),

or

12.8

nanoseconds.

The

frequency

is

then

the

reciprocal

of

12.8

nanoseconds,

or

about

78.1

megacycles.

An

alternative

method

for

measuring

frequency

or

repeti-

tion

rate

is

as

follows:

1.

Set

the

TIME/DIV.

switch

for

a

2-

to

10-cycle

display

of

the

input

signal.

2.

Count

the

exact

number

of

cycles

(including

fractional

cycles)

occurring

in

10

major

graticule

divisions.

3.

Multiply

the

number

of

cycles

obtained

in

step

2

by

the

Frequency

Multiplier

value

opposite

the

appropriate

TIME/DIV.

switch

setting

in

Table

3-1.

TABLE

3-1

TIME/DIV.

Setting

|

Frequency

Multiplier

1

nSEC

100mc™

10

nSEC

10

mc

1

SEC

1

me

1

»SEC

100

ke

10

wSEC

10

ke