Tektronix 7B53N Instruction Manual

TABLE

OF

CONTENTS

Introduction Simplified

Block

Diagram Discussion Main

Sweep

Mode

Delayed

Sweep

Mode

Mixed

Sweep

Mode

3-1 3-1 3-1

3-3

7B53N

Abbreviations

and

symbols

usedinthis

manual

are

based

on or

taken

directly

from IEEE

Standard

260

"Standard

Symbols

for

Units",

MIL

STD-12B,

and

other

standardsofthe

electronics

industry

.

SECTION

1

SPECIFICATION

Page

SECTION 3

CIRCUIT

DESCRIPTION

(cont)

Page

Introduction

1-1

Circuit

Operation

3-3

Table

1-1

Electrical

1-1

General Main

Trigger

Preamp

3-3 3-4

Main

Sweep

Triggering

1-1

Main

Trigger

Generator

3-5

Delayed

Sweep

Triggering 1-3

Main

Sweep

Generator

3-8

Main

Sweep

Generator

1-4

Delayed

Trigger

Preamp

3-11

Delayed

Sweep

Generator

1-4

Delayed

Trigger

Generator

3-12

Mixed

Sweep,

Variable

Time

Delay

1-5

Delayed

Sweep

Generator

3-13

Amplifier Output

Signals

1-5 1-6

Horizontal

Preamp

3-16

Table

1-2

Environmental

Characteristics

1-7

SECTION 4

MAINTENANCE

Table

1-3

Physical

1-7

Introduction

4-1

SECTION

2

OPERATING

INSTRUCTIONS

Preventive

Maintenance

4-1

Troubleshooting

4-2

General

2-1

Corrective

Maintenance

4-6

Installation

2-1

Controls

and

Connectors

2-2

SECTION

5

CALIBRATION

General

2-2

Main

Triggering

Controls

2-2

Introduction

5-1

Sweep

Controls

2-4

Tektronix

Field

Service

5-1

Delayed

Trigger

Controls

2-4

Using

This

Procedure

5-1

Front-Panel

Connectors

2-5

Test

Equipment

Required

5-1

Sweep

Calibration

2-6

Preliminary

Control

Settings

5-2

Simplified

Operating

Instructions

2-6

Part1Performance

Check

5-4

Main

Sweep

2-6

Index

to Part

I-Performance

Check

5-4

Magnified

Display

2-6

Preliminary

Procedure

for

Delayed

Sweep

Display

2-6

Performance

Check

5-4

Mixed

Sweep

Display

2-7

Trigger

System

Check

5-5

General

Operating

Instructions

2-7

Horizontal

System

Check

5-11

Pushbutton

Switch

Logic

2-7

Output

Signals

Check

5-17

Triggered

Light

2-7

Part11Adjustment

5-18

Main

Trigger

Mode

2-7

IndextoPart

11-Adjustment

5-18

Main

Trigger

Coupling

2-8

Preliminary

Adjustment

Procedure

5-18

Main

Trigger

Source

2-9

Trigger

System

Adjustment

5-19

Main

Trigger

Slope

2-10

Horizontal

System

Adjustment

5-25

Main

Trigger

Level

2-10

Output

Signals

5-29

Selecting

Sweep

Rates

2-10

Time

Measurement

2-10

SECTION

6

ELECTRICAL

PARTS

LIST

Sweep

Magnifier

2-12

Abbreviation

and

Symbols

Main

Sweep

Operation

2-12

Parts

Ordering Information

Delayed

Sweep

Operation

2-12

IndextoElectrical

Parts

List

Mixed

Sweep

Operation

2-13

Electrical

Parts

List

Delayed

Sweep

Triggering

2-13

Delayed

Gate

Output

2-14

SECTION

7

DIAGRAMS

AND

CIRCUIT

BOARD

Applications

2-14

ILLUSTRATIONS

General

2-14

Comparison

Measurement

Symbols

and

Reference

Designators

7-1

Techniques

2-14

Diagrams

Time

Duration

Measurements

2-15

Circuit

Board

Illustrations

Determining

Frequency

2-16

Risetime

Measurements

2-16

SECTION 8

MECHANICAL

PARTS

LIST

Delayed

Sweep

Measurements

2-17

Mechanical

Parts

List

Information

Delayed

Sweep

Magnification

2-18

IndexofMechanical

Parts

List

Triggered

Delayed

Sweep

and

Illustrations

Magnification

2-19

Mechanical

Parts

List

Pulse

Jitter

Measurements

2-19

Accessories

SECTION 3

CIRCUIT

DESCRIPTION

Introduction

The

7B53N

isadual

time

base unit

designed

for use

in

Tektronix

7000-Series

Oscilloscopes

withoutareadout

system

;

however

it is

compatible

with

all

7000-Series

Oscilloscopes

.

The

7B53N

features

calibrated

sweeps

from

5

seconds/division

to

50

nanoseconds/division

(5

nanoseconds/division

with

X10

magnification).The

Main

or

Delayed

sweep

rates

may

be

varied

continuously

(uncali-

brated)

between

calibrated

steps.Sweep

triggeringispro-

videdtoat least

100

megahertz,

Separate

trigger

controls

are

provided

to

select

the

desired

triggering

for

the

main

and

delayed

sweeps

.

O

SECTION

l

SPECIFICATION

TABLE

1-1

ELECTRICAL

MAIN

SWEEP TRIGGERING

7B53N

Four

display

modes

are

provided.These

include

separate

displayofthe

main

sweep,

an

intensified

display,

delayed

sweep,

and

mixed

sweep

.

The

7B53N

can

alsobeusedasan

amplifier

for

X-Y

operation

.

This

instrument

will

meet

the

electrical

characteristics

listed

under

Performance

Requirement

in

Table

1-1, fol-

lowing

complete

calibration

.

The

following

electrical

char-

acteristics

apply

over an

ambient

temperature

rangeof0°C

to

+50°C,

exceptasotherwise

indicated.Warmup

time

for

given

accuracyis20

minutes

.

Characteristic

Performance

Requirement

Supplemental

Information

Source

Internal

from

associated

vertical

unit

.

SelectedbySOURCE

switch

.

Internal

from

AC

power

source

.

External

dividebyten

.

Coupling

AC

SelectedbyCOUPLING

switch

.

AC

low-frequency

reject

.

AC

high-frequency

reject

.

DC

Polarity

Sweep

can

be

triggered

from

positive-

Selected

by

LEVEL/SLOPE

control

.

going

or

negative-going

portionoftrigger

signal

.

Internal

Trigger

Sensitivity

AC

0.3divisionofdeflection,

minimum, 30

The

specified

upper-3dB

frequency

hertz

to 10

megahertz;increasingto1

.5

of

the

vertical

system

supersedes

the

divisions

at

100

megahertz

.

frequency

limits

giveninthe

Internal

Trigger

Sensitivity

table

when

the

numberinthe

tableisgreater

than

the

upper-3dB

frequencyofthe

vertical

unit

.

Specification-7B53N

Performance

Requirement

0

.3

divisionofdeflection,

minimum,

30

kilohertz

to10megahertz;increasing

to

1

.5

divisionsat100

megahertz

.

0.3division

of

deflection,

minimum,

30

hertzto50

kilohertz

.

0.3division

of

deflection,

minimum,

DC

to 10

megahertz;increasingto1

.5

divi-

sion

at

100

megahertz

.

100

millivolts,

minimum,

30

hertz

to

10

megahertz

;

increasingto500

millivolts

at

100

megahertz

.

100

millivolts,

minimum,

150

kilohertz

to

10 megahertz;increasingto500

milli-

voltsat100

megahertz

.

100

millivolts,

minimum,

30

hertzto50

kilohertz

.

100

millivolts,

minimum,

DCto10

mega-

hertz;increasingto500

millivolts

at

100

megahertz

.

Stable

display

presented

with

signal

amplitudes

given

under

Internal

and

Ex-

ternal

Trigger

Sensitivity

above30hertz

.

Presentsafree-running

sweep

for

lower

frequenciesorin

absenceofa

trigger

signal

.

Main

Sweep

Generator

produces

only

one

sweep

when

triggered.Further

sweeps

are

locked

out

until

RESET

button

is

pressed.Trigger

sensitivity

sameasgiven

for

internal

and

external

sensitivity

.

1

nanosecondorless

at

75 megahertz

.

AC

LF

REJ

AC

HF

REJ

DC

External

Trigger

Sensitivity

AC

LF

REJ

AC

HF

REJ

DC

Auto

Triggering

Single

Sweep

Characteristic

Internal

Trigger

Jitter

External

Trigger

Input

InputRand

C

Maximum

Safe

Input

Voltage

TABLE

1-1

(cont)

Supplemental

Information

SOURCE

switch

settoEXT

.

Trig-

gering

signal

requirements

increased

10

times

for

EXT=10

position

.

Approximately1megohm

paralleled

by 20 pF

.

500

volts

(DC

+

Peak

AC).500

volts

peak-to-peakACat1kilohertzorless

.

Level

Range

EXT

TABLE

1-1

(cont)

Characteristic



I



Performance

Requirement

EXT-10

At

least

+

and

-1.5volts

.

At

least

+ and

-15

volts

.

DELAYED

SWEEP

TRIGGERING

Specification-71353N

Supplemental

Information

Source

Internal

from

associated

vertical

unit

Selected

by

Delayed

Triggering

SOURCE

switch

.

External

Coupling

AC

Selected

by

Delayed

Triggering

COUPLING

switch

.

DC

Polarity

Sweep

can be

triggered

from

positive-

Selected

by

Delayed

Triggering

SLOPE

goingornegative-going

portionoftrigger

switch

.

signal

.

Internal

Trigger

Sensitivity

AC

0.3divisionofdeflection,

minimum,

30

hertzto10

megahertz

;

increasingto1

.5

divisionsat100 megahertz

.

DC

0.3divisionofdeflection,

minimum,

DC

to

10

megahertz,

increasing

to1.5

divi-

sionsat100

megahertz

.

External

Trigger

Sensitivity

AC

100

millivolts,

minimum, 30

hertzto10 Delayed

Triggering

SOURCE

switch

megahertz;increasingto500

millivolts

at

settoEXT

.

100

megahertz

.

DC

100

millivolts,

minimum,

DC

to

10

mega-

hertz;increasing

to

500

millivoltsat100

megahertz

.

Internal

Trigger

Jitter

1

nanosecondorlessat75

megahertz

.

External

Trigger

Input

Maximum

Safe

Input

Voltage

500

volts

(DC+Peak

AC).500

volts

peak-to-peakACat1kilohertz

or

less

.

InputRand

C

1

megohm

paralleled

by 20

picofarads

.

Level

Range

At

least

+

and

-1.5volts

.

Specification-71353N

TABLE

1-1

(cont)

MAIN

SWEEP

GENERATOR

DELAYED

SWEEP

GENERATOR

Characteristic

Performance

Requirement

Supplemental

Information

Sweep

Accuracy

Measured

in

7400-

and

7500-Series

Oscilloscopes

Time

Interval

+15°C

to

+35

°

C

0°Cto

+50°C

Over

Center

8

Divisions

Unmagnified

Magnified

Unmagnified

Magnified

50

milliseconds/division

to

Within

2%

Within2.5%

Within

3%

Within

4%

0.5microsecond/division

5

seconds/division

to

0

.1

second/division

and0.2

Within

3%

Within

3

.5%

Within

4%

Within

5%

microsecond/division

to

0

.05

microsecond/division

Sweep

Linearity

Over

any2division

portion

with-

in

center

eight

divisions

(all

Within

5%

Within

7%

sweep

rates)

VARIABLE

Sweep

Rate

Range

Continuously

variable

between

calibrated

Extends

sweep

rate

to at least12.5

sweep

rates

.

seconds/division.VARIABLE

control

internally

switchable

between

Main

and

Delayed

Sweeps

.

Sweep

Hold-Off

Time

5

seconds/division

to

10 micro-

1.5times

the

TIM

E/DIVsettingorless

seconds/division

5

microseconds/division

to0.5

2.5microsecondsorless

microsecond/division

Normal-Mag

Registration

Within0.5

division

Sweep

Accuracy

Time

Interval

Measured

in

Oscilloscopes

.

+15°C

7400-Series

or

to

+35°C

7500-Series

00Cto50

°

C

Over

Center8Divisions

Unmagnified

Magnified

Unmagnified

Magnified

50

milliseconds/division

to

Within

3%

Within

3.5%

Within

4%

Within

5%

0.5microsecond/division

0.5second/divisionto0

.1

second/division

and0.2

Within

4%

Within4.5%

Within

5%

Within

6%

microsecond/division

to

0.5microsecond/division

Within2%± measured

Main

Sweep

error

Within

2%

Within

1%

Within0.2%offull

scale(1minor

divi-

sion)

Less

than1partin20,000

of the maxi-

mum

available

delay

time

(10 times

the

Main

Sweep

TIME/DIV

switch

setting)

.

Sweep

Accuracy

DELAY

TIME

MULT

Delay

Accuracy

over

center

eight

divisions

5

seconds/division to

1

second/division

0

.5

second/divisionto1

microsecond/division

Multiplier

Linearity

Delay

Time

Jitter

TABLE

1-1

(cont)

MIXED

SWEEP,

VARIABLE

TIME

DELAY

AMPLIFIER

Specification-71353N

Exclude

the following

portions

of

Mixed

Sweep

:

First

0

.5

division

after

startofMAIN

sweep

display

and0.2

divisionor1

microsecond

(whicheverisgreater)

after

transitionofMAIN

to

DLY'D

sweep

10

millivolts/division

within

10%

.

100

mill

ivolts/division

within

10%

.

1

volt/division

within

10%

.

Deflection

Factor

EXT,

MAG

X10

EXT,

MAG

off

EXT=

10,

MAG

off

Characteristic

Performance

Requirement

Supplemental

Information

Sweep

Linearity

Over

any2division

portion

with-

in

center

eight

divisions

(all

Within

6%

Within

8%

sweep

rates)

VARIABLE

Sweep

Rate

Range

Continuously

variable

between

calibrated

Extends

sweep

ratetoat

least

1

.25

sweep

rates

.

seconds/division.VARIABLE

control

internally

switchable

between

Main

and Delayed

Sweeps

.

Sweep

Hold-Off

Time

Determined

by

the

Main

Sweep

TIME/

DIV

setting

.

Specification-71353N

Performance

Requirement

Characteristic

TABLE

1-1

(cont)

.

OUTPUT

SIGNALS

Supplemental

Information

Delayed

Sweep

Gate

Availableatfront-panel

DLY'D

TRIG

IN

connector

when

operatingina

Waveshape

Rectangular

pulse

delayed

sweep

mode

with

the Delayed

Triggering

SOURCE

switch

settoINT

.

Amplitude

+3.5volts

within

40°%

with

baselineat0

to-1volt

.

Polarity

Positive-going

Duration

For

the

timeofthe

delayed

sweep

Output

Resistance

Approximately1kilohm

Loading

At

least10kilohms

shuntedby100

picofaradsorless

.

Composite

Sweep

Gate

Coupled

to

associated

indicator

oscilloscope

by

way

of

pinA1on

In-

Waveshape

Rectangular

pulse

.

terface

circuit

board

.

Polarity

Positive-going

Duration

DISPLAY

MODE

MAIN

SWP

Coincident

with

the

main

sweep

interval

.

INTEN

Coincident

with

the

main

sweep

interval

.

DLY'D

SWP

Coincident

with

the

delayed

sweep

in-

terval

.

MIXED

Coincident

with

the

main

sweep

interval

plus

the

delayed

sweep

interval

.

Nominal

Frequency

Response

System

-3 dB

pointsin7400-Series

or

7500-Series

Oscilloscope

.

AC

Lower-3dB

40

hertz

Upper-3dB

2 megahertz

AC

LF

REJ

16

kilohertz

2

megahertz

AC HF

REJ

40

hertz

100

kilohertz

DC

2 megahertz

Performance

Requirement

Rectangular

pulse

Positive-going

Coincident

with

the

delaying

sweep

(all

DISPLAY MODES)

Sawtooth

signal

with

slope

determined

by

settingofTIME/DIV

OR

DL'Y

TIME

switch

.

Sawtooth

signal

with

slope

determined

by

setting

of

DELAYED

SWEEP

Time/

Division

switch

.

Composite

Sawtooth

signal

with

slope

determinedbythe

settingofTIME/DIV

OR

DL'Y

TIME

switch

during

the main

sweep

portionofdisplay,

and

by

the

setting

of

DELAYED

SWEEP

Time/

Division

switch during

delayed

sweep

por-

tion of

display

.

Negative-going

Coincident

with

the main

sweep

interval

Ramp

duration

coincident

with

the

de-

layed

sweep

interval;total

duration

coin-

cident

with

the

delaying

sweep

interval

.

Ramp

duration

coincident

with

the

main

sweep

interval

plus

the

delayed

sweep

in-

terval;total

duration

coincident

with

the

delaying

sweep

interval

.

Auxiliary

Gate

Waveshape

Polarity

Duration

Composite Sawtooth

Waveshape

DISPLAY

MODE

MAIN

SWP

O

Polarity

Characteristic

INTEN

DLY'D

SWP

MIXED

Duration

DISPLAY

MODE

MAIN

SWP

INTEN

DLY'D

SWP

MIXED

TABLE

1-1

(cont)

TABLE

1-2



TABLE

1-3

ENVIRONMENTAL

CHARACTERISTIC

Refer

to

the

Specification

for

the

associated

oscillo-



Size

scbpe

.



Weight

Specification-7B53N

Supplemental

Information

Coupled

to

associated

indicator

oscil-

loscope

by

way

of

B5

on

Interface

board

.

Coupled

to

associated

indicator

oscilloscope

by

way

of pinsA3and

133

on

Interface

board

PHYSICAL

Fits

all

7000-series

plug-in

compartments

.

3

.25

pounds.(1

.48

kilograms)

General

Installation

SECTION

z

OPERATING

INSTRUCTIONS

The

7B53N

Dual

Time

Base

plug-in

Unit

operates

with

a

Tektronix

7000-Series

indicator

oscilloscope

and

a

7A-Series

vertical

plug-in

unit

to

form

a

complete

oscilloscope

system.To

effectively

use the

71353N,

its

operation

and

capabilities

should

be

known.This

section

describes

the

operation

of the

front-panel

controls,

gives

simplified

operating

instructions

and

general

operating

information,

and

lists

some

basic

applications

for

this

instrument

.

The

7B53Nisdesignedtooperate

in

the horizontal

plug-

in

compartment

of the

indicator

oscilloscope.This

instru-

ment

can

also

be

installedinthe

vertical

plug-in

compart-

ment

to

provideasweep

that

runs

vertically

on

the

CRT

.

However,

when

usedinthis

manner,

there

arenoretrace

blanking

or

internal triggering

provisions,

and

the

unit

may

not

meet

the

specifications

given

in

Section1.

The

instruc-

tions

in this

manual

are

written

for

use

of the

7B53N

in

the

horizontal

plug-in

compartment

.

The

7B53N

canbeoperatedinan

indicator oscilloscope

with

four

plug-in

compartments

either

independently,

in

the Alternate or

Chopped

Horizontal

Modes,

or

as

a

delayed

sweep

unit.However,

when

the

7B53N

is

operated

asadelayed

sweep

unit,itmust

be

triggered for

a

CRT

display.It

cannot

delay

another

time

base

unit,

butitcan

delay

its

own

internal

delayed

sweep

.

Before

proceeding

with

installation,

it is

necessary

to

check

the

setting

of

the

internal

Variable

Selector

switch

on

the

right

side

of

the

instrument

(see

Fig.2-1

for

location).The

Variable Selector

switch

determines

whether

the

front-panel

VARIABLE

control

operates

in

conjunction

with

the

main

or

delayed

sweeps

(see

controls

and

connectors

discussion

in

this

section

for

VARIABLE

control

operation)

.

To

install

the

7B53N

in

a

plug-in

compartment,

push

it

in

untilitfits

firmly

into

the

compartment.The

front-panel

of

the

7B53N

shouldbeflush

with

the

front-panel

of the

indicator

oscilloscope.Even

though

the gain of the

indica-

tor

oscilloscopeisstandardized

to

minimize

adjustment

when

inserting

plug-in

units,

the

sweep

calibration

of the

7B53N

should

be

checked

when

it is

installed

.

The

pro-

cedure

for

checking

the

unitisgiven

under

Sweep

Calibra-

tion

Check

in

this

section

.

7B53N

Fig.2-1.Location

of Variable Selector switch

.

To

remove

the

7B53N,

pull

the

release

latch

(see

Fig

.

2-2)todisengage

the unit

from

the

indicator

oscilloscope

and

pullitoutofthe

plug-in

compartment

.

Fig.2-2.Locationofrelease

latch

.

Operating Instructions-71353N

General

To

make

full

use

of

the

capabilitiesofthis

instrument,

the

operator

should

be

familiar

with

the

function

and

use

of

each

of

the

controls.A

brief

descriptionofthe

controls

and

connectorsisgiven

here

.

More

detailed

information

is

given

under

General

Operating

Information.Fig.2-3

shows

the

front-panel

and

external controls

and

connectors

of

the

7B53N

.

Main

Triggering

Controls

LEVEL/SLOPE



Selects

the amplitude

point

and

r

signal

on

which

the

gered

.

When

the

indi

the

outer

ringisto

the

sweepistriggered

ive-going

slopeofthe

trigger

signal, as

shown

by

the

g

waveform.To

the

ter,

the

sweepistrig-

negative-going

slope

of

signal as

shown

by

the

negative-going

waveform

.

2-2

CONTROLS

AND

CONNECTORS

slopeoftrigg sweepistri cator

line

on

left

of

cente

on

the

posi

positive-goi rightofce

geredonth the

trigger

TRIG'D



Lamp

indicates

that

the

sweep

is

triggered

and

will

produceadisplay

with

correct

setting

of

the

POSITION

control

and

the

controls

on

the

associated

vertical

unit

and

indicator

oscilloscope

.

MODE



Four

pushbutton

switchestoselect

the

desired

trigger

mode

.

AUTO

:

Sweep

initiatedbythe

applied

trigger

signal at

point

selectedbythe

LEVEL/SLOPE

control

when

the

trigger

signal

repetition

rateisabove about

30

hertz

and

within the

frequency

range

selected

by

the

COU-

PLING

switch.Triggered

sweep

can be

obtained only over

the

amplitude

rangeofthe

applied

trigger

signal

.

When

the

LEVEL/

SLOPE

controlisoutside

the

amplitude

range,

the

trigger

repetition

rateisoutside

the

fre-

quency

range

selected

by the

COUPLING

switch,orthe

trig-

ger

signalisinadequate,

the

sweep

free-runsatthe

sweep

rate

selected

by

the

TIME/DIV

OR

DL'Y

TIME

switch

.

COUPLING

NORM

:

Sweep

initiatedbythe

applied

trigger

signalatpoint

se-

lected

by

the

LEVEL/SLOPE

control

over the

frequency

range

selected

by

the

COUPLING

switch

.

Triggered

sweep

can

be

obtained only over

the

ampli-

tude

range

of the

applied

trigger

signal.Thereisno

trace

when

the

LEVEL/SLOPE

control

is

outside

the

amplitude

range,

the

trigger

repetition

rateisoutside

the frequency

range

selected

by

the

COUPLING

switch,

or the

trigger

signalisinadequate

.

SINGLE

SWP:After

a

sweepisdis-

played, further

sweeps

cannot

be

presented

until

the

RESET

but-

ton

is

pressed.Displayistrig-

geredasfor

NORM

operation,

using

the

MAIN

TRIGGERING

controls

.

RESET-READY

:

Pushbutton

to

reset

the

Sweep

Generator

for

the

in

the

SINGLE

SWP

mode.The

RESET-READY

button

remains

illuminated

to

indicate

that

the

unitisready

to

be

triggered.After

the

unit

is

triggered

andasweepiscom-

pleted,

the

RESET-READY

light

goes

out

until

the

button

is

pressed again

.

Four pushbutton

switchestoselect

trigger

coupling

.

AC

:

RejectsDCand

attenuates

AC

signals

below about

30

hertz

.

Accepts

signals

between

30

hertz

and 100

megahertz

.

AC

LF

REJ:RejectsDCand

atten-

AC

HF

REJ:Accepts

signals

be-

tween about

30

hertz

and

50

kilohertz

.

RejectsDCand

atten-

uates

signals

from

50

kilohertz

to

100

megahertz

.

O

uates

signals

below

about

30

kilohertz.Accepts

signals

be-

tween

30

kilohertz

and 100

megahertz

.

SOURCE

O

INT:Trigger

signal

obtained

in-

ternally

from

vertical

unit

by

way

of

associated

indicator

oscilloscope

.

Fig.2-3.Front-panel

controls

and

connectors

.

DC:Accepts

all

trigger

signals

from

DC

to

100

megahertz

.

Four

pushbutton

switches

to

select

the

trigger

source

.

Operating

Instructions-71353N

LINE:Trigger

signal

obtained

in-

ternally

from

a

sample

of the

line

voltage appliedtoassociated

indicator

oscilloscope

.

EXT:Trigger

signal

obtained

from

an

external

signal

applied to the

MAIN

TRIG

IN

connector

.

EXT

=10:Trigger

signal

obtained

from

an external

signal

applied

2-

3

Operating

Instructions-71353N

Sweep

Controls

POSITION

X10

MAG

SWP

CAL

TIME/DIV

OR

DL'Y

TIME

VARIABLE

2-

4

to

the

MAIN

TRIG

IN

con-

nector.In

this

position

the

ex-

ternal signalisattenuated

10

times

beforeitis

appliedtothe

trigger

circuit

.

Controls

the

horizontal position

of

trace

.

Increases

sweep

rateofboth

the

main and

delayed

sweeps

ten

times

by

horizontally expanding

the

center

division

of

display

.

Light

indicates

when

magnifierison

.

Screwdriver

adjustmenttoset

hori-

zontal

gain

of unit.Usedtoset

the

basic

timingofthe

7B53N

and

to

compensate

for

differencesinCRT

deflection factor

when

changing

indicator oscilloscopes

.

Combination

switch

selects

the

sweep

rates

for

both

the

main

and

delayed

sweep

generators

.

The

clear

plastic

flange

indicates

the

sweep

rateofthe main

sweep

circuit

for

main

sweep

display

only

and

indi-

cates

the

basic

delay

time

.(to

be

multipliedbythe

DELAY

TIME

MULT

dial

setting)

for

delayed

or

mixed sweep

operation.The

DELAYED

SWEEP

knob,

when

pulled

out and

rotated

clockwise,

selects

the

sweep

rateofthe

de-

layed

sweep

circuit

for

mixed

or

delayed

sweep

operation.The

VARIABLE

control

mustbein

the

CAL

position

and the

X10

MAG

switch

must

be

off

for

indicated

sweep

rate

.

Two

position switch

actuated

by

the

VARIABLE

knobtoselect

cali-

brated

or uncalibrated

sweep

rates

.

In

the

CAL

position

(pushed

in)

the

VARIABLE

controlisinoperative

and

the

sweep

rateiscalibrated

.

When

pressed

and

released,

the

knob

moves

out

to

activate

the

VARIABLE

control

for

uncali-

brated

sweep

rates.The

sweep

rate

in

each

TIME/DIV

switch

position

DISPLAY

MODE

DELAY

TIME

MULT

Delayed

Trigger

Controls

LEVEL

can be reducedatleasttothe

sweep

rate

of

the

position

.

The

VARIABLE

control

can

be

switchedtoeither

the main or

de-

layed

sweeps by

meansofthe

inter-

nal

Variable

Selector

switch

(see

In-

stallationinthis

section)

.

Four

pushbutton

switchestoselect

the

desired display

mode

.

MAIN

SWP:Sweep

rates

deter-

mined

by

the

TIME/DIV

OR

DL'Y

TIME

switch

.

INTEN:In

this

mode,aportion

of

the

main

sweep

is

intensified

during

the

time

that

the

delayed

sweepisin

operation,asdeter-

mined

by

the

DLY'D

SWEEP

Time/Division

switch

.

D

LY'D

SWP:The

DLY'D

SWP

mode

isafunction

of

the

delayed

sweep.In this

mode,

the

delayed

sweepisdisplayedata

rate

determined

by

the

DLY'D

SWP

Time/Division

switchatthe

end

of

each

delay

period,

as

determined

by

the

TIME/DIV

OR

DL'Y

TIME

switch

and

the

DELAY

TIME

MULT

dial

set-

tings

.

MIXED:The

MIXED

mode

is

a

combination

of

the

main

and

delayed

sweeps.The

main

sweep

is

displayedonthe

CRT

to

a

point

determined

by

the

DELAY

TIME

MULT

dial;the

remainderofthe

sweepisat

the

rate

determined

by the

delayed

sweep

.

Provides

variable

delayof0to10

times

the

basic

delay

time

selected

by

the

TIME/DIV

OR

DL'Y TIME

switch

.

Dual

function

controltodetermine

the

mode

and

level

for

delayed

sweep

display

.

O

SLOPE

COUPLING

SOURCE

IN-RUNS

AFTER

DLY

TIME

:

The

delayed

sweep

runs

immedi-

ately

following

the

delay

time

selectedbythe

TIME/DIV

OR

DL'Y

TIME

switch

and

the

DE-

LAY

TIME

MULT

dial.Delayed

SLOPE,

COUPLING,

SOURCE,

and

LEVEL

functions

inoperative

.

OUT-DLY'D

SWP

TRIGGER-

ABLE:When

the

LEVEL

con-

trolispressed

and

released

the

delayed

sweepistriggerable.The

LEVEL

control

can

now

be

ro-

tated

to

select

the

amplitude

point

on

the

trigger

signal at

which

the

delayed

sweepistrig-

gered.In

the

OUT-DLY'D

SWEEP

TRIGGERABLE

posi-

tion

the

delayed

SLOPE,

COUPLING,

and

SOURCE

func-

tions

are

activated

.

Two

position

switchtoselect

the

portion

of

trigger

signal

which

starts

the

delayed

sweep

.

+

:

The

delayed

sweep

canbetrig-

gered

from

positive-going

por-

tionoftrigger

signal

.

-:The

delayed

sweep

canbetrig-

gered

from

negative-going

por-

tion

of

trigger

signal

.

Two

position

switch

to

determine

the

method

of

coupling

delayed

trigger

signaltothe

delayed

trigger

circuit

.

AC:RejectsDCand

attenuates

AC

signals

below

about

30

hertz

.

DC:Accepts

trigger signals

from

DCto100

megahertz

.

Two

position

switch to

select

sourceofthe

delayed

trigger.Also

determines

the

function

of

the

DLY'D

TRIG

IN connector

.

INT

:

The

delayed

trigger

signal

is

obtained

from

the

vertical

ampli-

fier

unitbyway

of

the

associ-

ated

indicator

oscilloscope

.

Also

Front-Panel

Connectors

MAIN TRIG

IN

DLY'D

TRIG

IN

Operating

Instructions-71353N

connects

the

Delayed

Gate

Out

signaltothe

DLY'D

TRIG

IN

connector

for

external

use

.

EXT:The

delayed

trigger

signal

is

obtained

fromanexternal

signal

appliedtothe

DLY'D

TRIG

IN

connector

.

Front-panel

BNC

connector

serving

two

different

input

functions,

depending

upon

the

settingofthe

TIME/DIV

OR

DL'Y

TIME

switch

and

the

MAIN

TRIGGERING

SOURCE

switch

.

MAIN

TRIG

IN:External

trigger

input

for Jhe

Main

Triggering

cir-

cuit.The

SOURCE

switch

for

MAIN

TRIGGERING

must

be

set

to

EXT

or

EXT

=10

and

TIME/DIV

OR

DL'Y

TIME

switch

settoany

position

except

AMPL

.

AMPL:When

the

TIME/DIV

OR

DL'Y

TIME

switchisset

to

AMPL

and

the

MAIN

TRIG-

GERING

SOURCE

switchisset

to

the

EXT

or

EXT

=10

posi-

tion,

this

connector

serves

as an

External

Horizontal

Input

.

Front-panel

BNC

connector

serving

two

different

functions

depending

upon

the

settingofthe

Delayed

Triggering

SOURCE

switch

.

DLY'D

TRIG

IN:When

the

Delayed

Trigger

SOURCE

switch

is

settoEXT,

this

connector

servesasan

external

trigger

in-

put

for the

delayed

triggering

circuit

.

Delayed

Gate

Output:When

the

Delayed

Trigger

SOURCE

switch

is

settoINT

the

DLY'D TRIG

IN

connector

servesasa

Delayed

Gate

Output.The

Delayed

Gate

signal

is

a

rectangular

positive-

going

pulse

with

approximately

3.5volts

amplitude

and

pulse

width

coincident

with

the

delayed

sweep

.

2-5

Operating

Instructions-71353N

Sweep

Calibration

Check

Whenever

the

7B53Nisinserted intoaplug-in

compart-

ment

of an

indicator oscilloscope

other

than

the

one

in

which

it

was

originally

calibrated,

the

sweep

calibration

must

be

checked,

and

readjusted

if

necessary.Install

the

7B53N

into

the

plug-in

compartment

of

the

indicator

oscilloscope

and

allowatleast

20

minutes

warmup

before

proceeding

with

the following

:

For

accurate

sweep

timing,

applyasignal

of

known

fre-

quency

or time

period

(time-mark

signal,

calibrator

square-

vyave,

60-hertz

line,

etc.)to

the

associated

vertical

amplifier

unit

and

adjust

the

TIME/DIV

OR

DL'Y

TIME

switch

and

the

SWP CAL

controltocalibrate

that

signaltothe

oscillo-

scope

graticule.The

following

method,

using

a

Tektronix

2901

Time Mark

Generator,

is

recommended

.

1.Connecta1

millisecond

time-mark

signal

from

the

time-mark

generator

through a

50-ohm

BNC

coaxial

cable

to

the

Input

of

the

associated

vertical

unit

.

2.Set the

7B53N

TIME/DIV

OR

DL'Y

TIME

switch

to

1msand

press

the

VARIABLE

controltothe

CAL

posi-

tion.Press

the

MAIN

TRIGGERING AUTO,

AC,

and

INT

switches

.

3.Set

the

vertical

unit

foraCRT

display

amplitude

of

twotofour

divisions

usingDCcoupling

.

4.Rotate

the

LEVEL/SLOPE

control

foratriggered

display

.

5

.

Check

the

CRT

display

for

one

marker

each

major

graticule

division

over

center

eight

divisions

.

6.Adjust

SWP

CAL

(front-panel

screwdriver

adjust-

ment),

for

one

marker

each

major

division.Use

the

POSITION

controlasnecessarytoalign

the

display

with

the

vertical

graticule

lines

.

The

following

informationisprovidedtoaidinquickly

obtaining the

correct

settings

for the

7B53N

to

present

a

display.The

operator

shouldbefamilar

with the complete

function

and

operationofthe

unit

describedinthis

section

before

using

this

procedure

.

Main

Sweep

The

following

procedure

will

provideastable

display

for

most main

sweep

applications

:

2-6

SIMPLIFIED

OPERATING

INSTRUCTIONS

1.Select

the

MODE,

COUPLING,

and

SOURCE

push-

buttonofthe

MAIN

TRIGGERING

switches

which

fit

the

requirements

of

the

signal

to be

displayed

.

2.Press

the

MAIN

SWP

pushbuttonofthe

DISPLAY

MODE

switch

.

3.Turn

the

LEVEL/SLOPE

control

to

the

desired

slope

.

4.If

the

green

TRIG'D

lightisnot

on,

adjust

the

LEVEL/SLOPE

control

throughout

the

range

of

the

selected

SLOPE

until

the

TRIG'D

light

comes

on

.

If

the

light

does

not

come

onatany

setting

of

the

LEVEL/

SLOPE

control,

the

trigger

signalisnot

adequate

or

the

COUPLING

and

SOURCE

switches

are

set

incorrectly

.

5.Set

the

TIME/DIV

or

DL'Y

TIME

switch

and

POSITION

control

foradisplay

which

remains

on

the

dis-

play area horizontally

(VARIABLE

control

shouldbein

CAL

position

for

calibrated

sweep

rates)

.

6

.

If

the

display

does not

startatthe

correct

point

on

the

waveform,

readjust

the

LEVEL/SLOPE

control

for

the

desired

triggering

.

Magnified

Display

A

magnified-sweep

display

canbeobtainedasfollows

after

a

normal-sweep

displayisobtained

:

1.Adjust

the

POSITION

control

to

move

the

area to

be

magnified

within the

center

divisionofthe

CRT

.

2.If

necessary,

change

the

TIME/DIV

or

DELAY

TIME

switch

settingsothe

complete

area tobemagnified

is

within

the

center

graticule

division

.

3.Press

and

release

the

X10

MAG

switch.Light

indi-

cates

when

magnifierison

(the

indicator

oscilloscope

Inten-

sity

may

need to be

increasedtoview

magnified

display)

.

4.Use the

POSITION

control

to

establish

precise

positioningofthe

magnified

display

.

Delayed

Sweep

Display

The

following

procedureisrecommended

for use

of

INTEN

and

DLY'D

SWP

DISPLAY

MODES.Obtainadis-

play as previously

given

under

Main Sweep,

then

proceed

as

follows

:

O

1.Press

the

X10

MAG

switchin(off)

and

press

the

Delayed

Triggering

LEVEL

control

to

the

IN-RUNS

AFTER

DLY

TIME

position

.

2

.

Press

the

INTEN

pushbuttonofthe

DISPLAY

MODE

switch.Pull

out

the

DLY'D

SWEEP

Time/Division

switch

and

rotate

clockwisetoobtain the

amountofmagnification

desired.Note

that

a normal

sweep

(Main Sweep)

with

an

intensified

portion

(Delayed

Sweep)isdisplayedonthe

CRT.The

indicator

oscilloscope

Intensity

may

have

to be

decreased

to

view

the

intensified

display

.

3.Rotate

the

DELAY

TIME

MULT

dial

and

note

that

the

intensified

portionofthe

displayiscontrolledbythe

DELAY

TIME

MULT

.

4.Press

the

DLY'D

SWP

button

of

the

DISPLAY

MODE

switch

.

Note

the

magnified

display,asdetermined

by the

DLY'D

SWEEP

Time/Division

switch.The

Intensity

may

needtobe

increasedtosee the

delayed

sweep

display

.

5.Foradelayed

sweep

with

less

jitter,

pressinand

release

the

Delayed

Triggering

LEVEL

control.Delayed

triggering

SLOPE,

COUPLING,

and

SOURCE

switches

shouldbesetto+,

AC,

and

INT

respectively

.

Rotate the

Delayed

Triggering

LEVEL

control

forastable

delayed

sweep

display

.

Mixed

Sweep

Display

The

procedure

that

follows

can be

used

for

basic

mixed

sweep

operation.Obtain a

display

as

previously

given

under

Main

sweep.Then

proceedasfollows

:

1.Press

the

MIXED

pushbutton

of

the

DISPLAY

MODE

switch

and

press

and Delayed

Triggering

LEVEL

controltothe

IN-RUNS

AFTER

DLY

TIME

position

.

2.Pull

out

the

DLY'D

SWEEP

Time/Division

switch

and

turn

clockwisetoset

the

sweep

rate

for

the

delayed

portionofdisplay

.

3.Adjust

DELAY

TIME

MULT

dialtovary

the

point

at

which

the

display

switches

from

the

MaintoDelayed

sweep

rate

.

4.If

less

jitter

is

desired

for

the

delayed

sweep

portion

of

the

mixed

sweep

display,

pressinand

release

the De-

layed

Triggering

LEVEL

control.Delayed

Triggering

SLOPE,

COUPLING,

and

SOURCE

switches

shouldbeset

to

+,

AC,

and

INT

respectively.Rotate

the

Delayed

Triggering

LEVEL

controltotrigger

the

delayed

sweep

portionofdisplay

.

GENERAL

OPERATING

INSTRUCTIONS

Pushbutton

Switch

Logic

Operating

Instructions-71353N

The

MODE,

COUPLING,

and

SOURCE

pushbuttons

of

the

MAIN

TRIGGERING

switches

and

the

DISPLAY

MODE

pushbuttons

are

arrangedina

sequence

which

places

the

most-often

used

position at

the

topofeach

series

of

pushbuttons.With

this

arrangement,astable

display

can

usuallybeobtained

by

pressing

the

top pushbuttons

:

AUTO,

AC,

INT,

and

MAIN

SWP.When

an

adequate

trigger

signalisapplied,

the

unitistriggered

as

indicated

by the

illuminated

TRIG'D

light,

with

the

correct

settingofthe

LEVEL/SLOPE

control.If

the

TRIG'D

lightisnot

on,

the

LEVEL/SLOPE

controlisatasetting

outside

the

range

of

the

trigger

signal

appliedtothis

unit

from

the

vertical

unit

;

the

trigger

signalisinadequate,orits

frequency

is

below

the

lower

frequency

limit

of

theACCOUPLING

switch

posi-

tion.If

the

desired display

is

not

obtained with

these push-

buttons

pushed

in,

other

selections

mustbemade.Refer

to

the following

discussionsorthe

instruction

manuals

for the

associated

indicator oscilloscope

and

vertical

unit

for

more

information

.

Triggered

Light

The

TRIG'D

light

provides

a

convenient

indication

of

the

condition

of

the

triggering

circuits.If

the

MAIN

TRIGGERING

controls

are

correctly

set

andanadequate

trigger

signalisapplied,

the

TRIG'D

lightison.Under

certain

conditions,

the

TRIG'D

light

maybeoff,

indicating

that

the

sweepisnot

triggered.The

cause

might beamis-

adjusted

LEVEL/SLOPE

control,

incorrectly

set

COUPLING

or

SOURCE

switches,

low

trigger

signal

ampli-

tude,ora

trigger

signal

repetition

rate

outside

the

accept-

able

frequency

range.This

light

can be

usedasa

general

indicationofcorrect

triggering.It is

particularly

useful

when

settingupthe

trigger circuits

whenatrigger

signal

is

available

withoutadisplayonthe

CRT

.

Main

Trigger

Mode

The

pushbuttons

located

under

the

MODE

title

select

the

modeinwhich

the main

sweepistriggered

.

AUTO.When

the

AUTO

pushbuttonispressed,atrig-

gered

display

is

presented

with

the

correct

settingofthe

LEVEL/SLOPE

control

(see

Trigger

Level

discussion)

whenever

an adequate

trigger

signalisapplied.The

TRIG'D

light

indicates

when

the

displayistriggered

.

When

the

trigger

repetition

rateisbelow about30hertz

(or

outside

the

frequency

range

selectedbythe

COUPLING

switch)orwhen

the

trigger

signalisinadequate,

the

sweep

free

runsatthe

sweep

rate

indicated

by the

TIME/DIV

or

DELAY

TIME

switch

(TRIG'D

light

off)

.

When

an

ade-

quate

trigger

signal

is

again

applied,

the

free-running con-

2-

7

Operating Instructions-71353N

dition

ends

and

a

triggered

displayispresented.When

the

LEVEL/SLOPE

controlisatasetting

outside

the

amplitude

rangeofthe

trigger

signal,

the

sweep

also

free

runs

at

the

sweep

rate

indicatedbythe

TIME/DIV

or

DELAY

TIME

switch.This

type

of free-running

display

can be

useful

when

it is

desiredtomeasure

only

the

maximum

peak-to-

peak

amplitude

ofasignal

without

observing

the

waveshape

(suchasin

bandwidth

measurements)

.

When

the

display

is

ofamuch

greater

amplitude

than

canbedisplayedonthe

CRT,

the

sweep

willbetriggeredinall

positionsofthe

LEVEL/SLOPE

control

and

will

not

free-run

.

NORM.When

the

NORM

pushbuttonispressed,atrig-

gered display

is

presented

with

the

correct

settingofthe

LEVEL/SLOPE

control

wheneveranadequate

trigger

signal

is

applied

.

The

TRIG'D

light

indicates

when

the

display

is

triggered

.

The

NORM

trigger

mode

mustbeusedtoproduce

trig-

.

gered

displays

with

trigger

repetition

rates

below about

30

hertz.When

the

LEVEL/SLOPE

controlisatasetting

out-

side

the amplitude

rangeofthe

trigger

signal,

when

the

trigger

repeitition rateisoutside

the

frequency

range

selectedbythe

COUPLING

switch,

or

when

the

trigger

signalisinadequate,

thereisno

trace

(TRIG'D

lightisoff)

.

SINGLE

SWEEP.When

the

signal

to be

displayed

is

not

repetitiveorvariesinamplitude,

waveshape,

or

repetition

rate,aconventional

repetitive

type

display

may

produce

an

unstable

presentation.A

stable

display

can

often

be

obtained

under

these

circumstancesbyusing

the

single-

sweep

feature

of

this

unit.The

single-sweep

modeisalso

useful

to

photograph

non-repetitiveorunstable

displays

.

To

obtainasingle-sweep

displayofa

repetitive

signal,

first

obtain the

best

possible

displayinthe

NORM

MODE

.

Then

without

changing

the

other

MAIN

TRIGGERING

switches,

press

the

SINGLE

SWP

pushbutton.When

ready

to

view

the

single-sweep

display,

press

the

RESET-READY

pushbutton.A

single

traceispresented

each time

the

RESET-READY

pushbutton

is

pressed

(as

longasthe

repetitive

signal

remains

connected

to

the

system

and

MAIN

TRIGGERING

switches

are

correctly

set);further

sweeps

cannot be

presented

until

the

RESET-READY

push-

buttonispressed again.If

the

displayed

signalisa

complex

waveform composed

of pulses of

varying

amplitude,

successive

single-sweep

displays

may

not

start at

the

same

pointofthe

waveform.To

avoid

confusion

duetothe

CRT

persistence,

allow

the

displaytodisappear

before

pressing

the

RESET-READY

pushbutton

again.At

fast

sweep

rates,

it

may

be

difficulttoview

the

single-sweep

display.The

apparent

trace

intensity

canbeincreasedbyreducing

the

ambient

light

levelorusingaviewing

hoodasrecommended

in

the

indicator

oscilloscope

instruction

manual

.

Non-repetitive,

random

signals

can be

displayedinthe

single-sweep

mode

by

first

obtaining,the

best possible

dis-

2-

8

playinthe

NORM MODE

withasignal

whichisabout

the

same

amplitude

and

frequencyasthe

random

signal.Then

without

changing

the

other

MAIN

TRIGGERING

controls,

press

the

SINGLE-SWP

pushbutton.When

ready

for

the

random

signal,

press

the

RESET-READY

pushbutton.The

RESET-READY

pushbutton

remains

illuminated

to

indi-

cate that

the

unit

has

been

reset

andisreadytoproduce

a

sweep

.

The

light

goes

out

after

the

single

sweep

has

been

displayed.To

prepare

the

unit

for

another

single-sweep

dis-

play, press

the

RESET-READY

pushbutton

.

When

using

the

single-sweep

mode

to

photograph wave-

forms, the

graticule

mustbephotographed

separatelyinthe

normal

manner

to

prevent over-exposing

the

film.Be

sure

the

camera

systemiswell

protected

against

stray

light,

or

operate

the

system

inadarkened

room.For

repetitive

waveforms,

press

the

RESET-READY

pushbutton

only

once

for

each

waveform

unless

the

signal

is

completely

symmetrical.Otherwise,

multiple

waveforms

may

appear

on

the

film.For

random

signals,

the

lens

can be

left

open

until

the

random

signal triggers

the

unit

(RESET-READY

push-

button

illuminated).Further informationonphotographic

techniqueisgiveninthe

appropriate

camera

instruction

manual

.

RESET-READY

.

The

RESET-READY

pushbutton

re-

sets

the

main sweep

generator

for

the

when

operatinginthe

SINGLE

SWP

MODE.See

the

preceeding

Single

Sweep

discussion

for

more

information

.

Main

Trigger

Coupling

The

MAIN

TRIGGERING

pushbuttons

located

below

the

COUPLING

title

select

the

method

in

which

the

trigger

signalisconnectedtothe

trigger

circuits.Each

position

permits

selection

or

rejectionofthe

frequency

components

of

the

trigger

signal

which

trigger

the

sweep.Fig.2-4 graph-

ically

illustrates

the

bandoffrequencies

coveredbyeach

positionofthe

COUPLING

switch

.

AC.In

the

AC

position

of the

COUPLING

switch,

the

DC

component

of

the

trigger

signal

is

blocked.Signals

with

low-frequency

components

below about

30

hertz

are

attenuated.In

general,ACCOUPLING

can be

used

for

most

applications.However,ifthe

signal

contains

unwanted

frequency

componentsorif

the

sweepisto

be

triggeredata

low

repetition

rateorDC

level,

one

of

the

remaining

COUPLING

switch

positions

will

provideabetter

display

.

The

triggering

point

in

the

AC

position

of the

COU-

PLING

switch

depends

upon

the

average voltage

levelofthe

trigger

signal.If

the

trigger

signal

occurs

randomly,

the

average

voltage

level will

vary,

causing

the

triggering

point

to vary

also.This

shift

of

the

triggering

point

may

be

enough

so

it is

impossibletomaintainastable

display.In

such

cases,

useDCcoupling

.

O

AC

LF

REJ.In

the

AC

LF

REJ

position

of the

COU-

PLING

switch,

DC

is

rejected

and

low-frequency

trigger

signals

below about

30

kilohertz

are

attenuated.Therefore,

the

sweepistriggered

only

by

the

higher-frequency

com-

ponents

of the

trigger

signal.This

positionisparticularly

useful

for

providing

stable

triggeringifthe

trigger

signal

contains

line-frequency

components.Also, the

AC

LF REJ

position

provides

the

best

alternate-mode

vertical

displays

at fast

sweep

rates

when

comparing twoormore

unrelated

signals

.

AC

HF

REJ.The

AC HF

REJ

position

of the

COU-

PLING

switch

passes

all

low-frequency

signals

between

about

30

hertz

and

50

kilohertz

.

DCisrejected

and

signals

outside the

above

range

are

attenuated.When

triggering

from

complex

waveforms,

this

positionisusefultoprovide

a

stable

display

of the

low-frequency

components

.

DC.The

DC

positionofthe

COUPLING

switch

can

be

usedtoprovide

stable

triggering

with

low-frequency

signals

which

would

be

attenuatedinthe

other

modes,

or

with

low-repetition

rate

signals.It

can

alsobeusedtotrigger

the

sweep

when

the

trigger

signal

reaches aDClevel

selected

by

the

setting

of the

LEVEL/SLOPE

control.When

using

internal

triggering,

the

settingofthe

vertical

unit

position

controls

affects

theDCtriggering

point

.

Fig.2-4.Frequency

rangeofeach

COUPLING

switch position

.

Main

Trigger

Source

Operating

Instructions-71353N

The

MAIN

TRIGGERING

pushbuttons

located

below

the

SOURCE

title

select

the

source

of the

trigger

signal

whichisconnectedtothe

main

trigger

circuits

.

INT.In

the

INT

positionofthe

SOURCE

switch, the

trigger

signalisderived

from

the

associated

vertical

unit

.

Further

selection

of the

internal

trigger

signal

may

be pro-

vided

by

the

associated

vertical

unit

or

indicator

oscillo-

scope;see the

instruction

manuals

for these

instruments

for

information.For

most

applications,

theINT

position

of the

SOURCE

switch

canbeused.However,

some

applications

require

special

triggering

which

cannot

be

obtainedinthe

INT

position

of the

SOURCE

switch.In

such

cases

LINE

or

EXT

positions of the

SOURCE

switch

mustbeused

.

LINE.The

LINE

position

of the

SOURCE

switch con-

nectsasample

of the

power-line

voltage

from

the

indicator

oscilloscope

to the

trigger circuit.Line

triggeringisuseful

when

the

input

signalistime-related (multiple

or

sub-

multiple)

to

the

line

frequency.Itisalso

useful

for

pro-

viding a

stable

displayofa

line-frequency

component

in a

complex

waveform

.

EXT.An

external

signal

connected

to the

MAIN

TRIG

IN

connector

canbeused to

trigger

the

sweepinthe

EXT

2-

9

Operating

Instructions-71353N

position of

the

SOURCE

switch.The

external

signal

must

be

time-relatedtothe

displayed

waveform

forastable

dis-

play.An

external

trigger

signal

can be

usedtoprovide

a

triggered

display

when

the

internal

signalistoo

low

in

amplitude

for

correct

triggering,orcontains

signal

com-

ponentsonwhichitis

not

desiredtotrigger.Itisalso

useful

when

signal

tracinginamplifiers,

phase-shift

networks,

wave-shaping

circuits,

etc.The

signal

fromasingle

point

in

the

circuit

under

test

can be connectedtothe

EXT

TRIG

IN connector throughaprobeorcable.The

sweepisthen

triggered

by the

same

signalatall

times

and

allows

ampli-

tude,

time

relationship,orwaveshape

changesofsignals

at

various

points

in

the

circuittobe

examined

without

re-

setting

the

MAIN

TRIGGERING

controls

.

EXT

=10.Operationinthe

EXT

=10

position of

the

SOURCE

switchisthe

same

as

described for

EXT

except

that

the

external

signalisattenuated10times.Attenuation

of

high-amplitude

external

trigger signalsisdesirable

to

broaden

the

rangeofthe

LEVEL/SLOPE

control

.

Main

Trigger

Slope

The

LEVEL/SLOPE

control

determines

whether

the

trigger circuit

responds

on

the

positive-going

or

negative-going

portion

of

the

trigger

signal.When

the

indi-

cator

line

on the

outer

ring

of the

LEVEL/SLOPE

control

istothe

leftofcenter,

the

dispaly

startsonthe

positive-

going

portionofthe

waveform

(notice

positive-going

wave-

formtoleftofcontrol).To

the

right

of

center,

the

display

startsonthe

negative-going

portion

of

the

waveform

(notice negative-going

waveform).Fig.2-5

illustrates

the

operationofthe

LEVEL/SLOPE

controlatdifferent

levels

and

slopesofthe displayed

waveform.When

several

cycles

of

a

signal

appearinthe

display,

the

selectionof-the

trigger

slopeisoften

unimportant.However,ifonlyacertain

port-

ionofa

cycleistobedisplayed,

correct

settingofthe

LEVEL/SLOPE

controlisimportanttoprovideadisplay

which

startsonthe

desired

slopeofthe

input-signal

.

Main

Trigger

Level

In

addition to

selecting

the

trigger

slope,

the

LEVEL/

SLOPE

control

determines

the

voltage

levelonthe

trigger

signalatwhich

the

displayistriggered.The

horizontal

lines

marked

on

the

waveforms

to the

left

and

rightofthe

LEVEL/SLOPE

control represent

the

zero-volt

levelofthe

triggering

signal.When

the

LEVEL/SLOPE

controlisset

to

the

lineoneither

the

positive-goingornegative-going

wave-

form,

the

sweepistriggered

near

the

zero-volt

levelofthe

trigger

signal

.

As

the

LEVEL/SLOPE

controlisrotated

away

from

this

line,

the

displayed

waveform

startsata

point

correspondingtothe

position of

the

indicator

line

on

the

associated

slope

waveform.For

example,ifthe

LEVEL/

SLOPE

controlisturned

clockwise

from

the

line

on

the

positive-going

slope,

the displayed

waveform

startsata

more

positive

level

.

2-10

Before

setting

the

triggering

level,

the

desired

SLOPE,

MODE,

COUPLING,

and

SOURCE

should

be

selected

for

MAIN

TRIGGERING

.

Then

adjust

the

LEVEL/SLOPE

control

so

the displayed

waveform

starts

from

the

desired

point

.

The

triggering

slope

canbechangedatany

time

by

rotating

the

LEVEL/SLOPE

control

to the

corresponding

pointonthe

other

slope

waveform

.

Selecting

Sweep

Rates

The

TIME/DIV

OR

DL'Y

TIME

switch

selects

calibrated

sweep

rates

for

the

Main

Sweep

Generator,

and

the

DE-

LAYED

SWEEP

Time/Division

switch

selects

calibrated

sweep

rates

for

the

Delayed

Sweep

Generator

.

The

sweep

rateofthe Main

Sweep

Generatorisbracketedbythe

black

lines

on the

clear

plastic

flange of

the

TIME/DIV

OR

DL'Y

TIME

switch

(see

Fig

.

2-6).Sweep

rateofthe Delayed

Sweep

Generatorisindicatedbythe

white

line

on

the

DE-

LAYED

SWEEP

knob.When

the

white

line

on

the

outer

knobissettothe

same

positionasthe

linesonthe

inner

knob,

the

two

knobs

lock

together

and the

sweep

rate

of

both

generatorsischangedatthe

same

time.However,

when

the

DELAYED

SWEEP

Time/Division

knobispulled

outward,

the

clear

plastic

flangeisdisengaged

and

only

the

Delayed

Sweep

Generator

sweep

rate

is

changed.This

al-

lows

changing

the

delayed

sweep

rate

without

changing

the

delay

time

determinedbythe

Main

Sweep

Generator

.

A

VARIABLE

control

is

provided

concentric

with

the

TIME/DIV

OR

DELAY

TIME

and

DELAYED

SWEEP

Time/Division

switches.This

control

can be

used

either

with

the

main

or

delayed

sweep

generator.The

internal

Variable Selector switch

(see

Fig.2-1

for

location)

deter-

mines

which

sweep

generator the

VARIABLE

control oper-

ates

with.The

VARIABLE

control

also

incorporatesatwo

position

switch

to

determine

if

the

applicable

sweep

rate

is

calibrated

or uncalibrated.When

the

VARIABLE

knob

is

pressed

in,

it is

inoperative.However,

when

pressed

and

released,

the

VARIABLE

controlisactivated

for

uncalib-

rated

sweep

rates.The

sweep

rate

canbereturnedtothe

calibrated

position

by

pressing

the

VARIABLE

control

.

This

featureisuseful

whenaspecific

uncalibrated

sweep

rate

has

been

obtained

and

it is

desiredtoswitch

between

calibrated

and

uncalibrated

sweep

rates.Switching

from

un-

calibratedtocalibrated

and

vice-versa

does

not

affect

the

settingofthe

VARIABLE

control.The

VARIABLE

control

allows

the

sweep

rateineach

Time/Division

switch

position

to

be

reducedtoat least

the

switch

position

.

Time

Measurement

When

making

time

measurements

from

the

graticule,

the

center

eight

graticule divisions

provide

the

most

linear

time

measurements

(see

Fig.2-7).Position

the

startofthe timing

area to

the

second

vertical

line

and

adjust

the

TIME/DIV

OR

DL'Y

TIME

switchsothe

end

of

the

timing

area

falls

between

the

second

and

tenth

vertical lines

.

CRT

displays

obtained

with

LEVEL/SLOPE

control

in

positive-slope

region

CRT

displays

obtained with

LEVEL/SLOPE

control

in

negative-slope

region

TRIG'D

EVELISLOPE

ma

mmmomm

umummmummm

mvxmuuxxmu mmummmmrrrmm

ammummummm mmmmmmmmmm

NIMENEEMENIN

mmmmm

youffffmuffm mummummumm offiammmmamm

"K1"

1/\VAR

"M

"

1

MrEWEENEEN

mommommomm

Negative

(-)slope

Fig.2-5.Effect of

LEVEL/SLOPE

controlonCRT

display

(AUTOorNORM

MODE)

.

Operating

Instructions-7B53N

2-

1 1

Operating

Instructions-71353N

Fig.2-6.Main

and

delayed

time/division

switch

.

Sweep

Magnifier

2-1

2

Brackets

enclose

main

Sweep

rate

ndicates

delayed

rat'!

Mainordelayed

sweep

VARIABLE

Second-vertical

Tenth-vertical

line line

Time Measurement

.

area

Fig

.

2-7.Area

of

graticule

used

for

accurate

time

measurements

.

The

sweep

magnifier

canbeused to

expand

each

sweep

rate

ten times.The

center

division

of the

unmagnified

dis-

playisthe

portion

visibleonthe

CRT

in

the

magnified

form

(see

Fig.2-8).Equivalent

length

of the

magnified

sweepismore

than

100

divisions;any

10

division

portion

canbeviewed

by

adjusting

the

POSITION

controltobring

the

desired

portion

onto

the

viewing

area

.

To

use

sweep

magnification,

first

move

the

portion

of

the

display

whichisto be

expanded

to the center of

the

graticule.Then

press

and

release

the

X10

MAG

pushbutton

(concentric

with

POSITION

control);the

X10

MAG

lamp

indicates

that the

sweep

rateismagnified.Whenever

the

X10

MAG

indicatorisilluminated,

the

equivalent

magnified

sweep

rate

can

be

determined

by

dividing

the

TIME/DIV

Fig

.

2-8.OperationofSweep

Magnifier

.

OR

DL'Y

TIME

switch

settingby10.For

example,ifthe

TIME/DIV

OR

DL'Y

TIME

switchissetto.5

us,

the

equi-

valent

magnified

sweep

rateis5

nanoseconds/division.The

equivalent

magnified

sweep

rate

must

be

used

for

all

time

measurements

when

the

X10

MAG

indicatorisilluminated

.

The

equivalent

magnified

sweep

rateiscalibrated

when

the

VARIABLE

controlisin

the

calibrated

position

.

Main

Sweep

Operation

For

main

sweep

displays,

press

the

MAIN

SWP

push-

button

of

the

DISPLAY

MODE

switch.In this

mode

the

TIME/DIV

OR

DL'Y

TIME

switch

selects

the

sweep

rate

for

the

main

sweep

circuit.Calibrated

sweep

rates

from

5

seconds

to

50

nanoseconds/division

are

provided

by

the

TIME/DIV

OR

DL'Y

TIME

switch

(5

nanoseconds

with

X10

magnification).By

using the

VARIABLE

control

(internal

Variable Selector switch

must

beinthe

Main

Time/Div

Variable

position)

uncalibrated

sweep

rates

to

12.5seconds/division

are

available

.

Delayed

Sweep

Operation

The

delayed

sweepisoperableinthe

INTEN,

DLY'D

SWP,

and

MIXED

positions

of the

DISPLAY

MODE

switch

.

ONE

so

-

MAG

switch

off

to

X10

Magnified

waveform

Calibrated

delayed

sweep

rates,

as

determined

by

the

DLY'D

SWEEP

Time/Division

switch,

are

available

from

0.5seconds

to

50

nanoseconds/division

(5

nanoseconds/

division

with

X10

magnification).Uncalibrated

delayed

sweep

rates

to1.25

seconds/division

canbe

obtained

by

using

the

VARIABLE

control

(internal

Variable Selector

switch

must

beinthe

Delayed

Time/Div

Variable

position)

.

The

INTEN

position

of

the

DISPLAY

MODE

switch

provides

an

intensified

portion

on

the

main sweep

during

the

time

that

the

delayed

sweep

isinoperation.The

amount

of

delay

time

between

the

start

of

the

main sweep

and the

intensified

portionisdetermined

by

the

TIME/DIV

OR

DL'Y

TIME

switch

and

the

DELAY

TIME

MULT

dial

.

When

the

DLY'D

SWP

pushbutton

is

pressed,

the

inten-

sified

portion,

as

viewed

when

the

DISPLAY

MODE

switch

isinthe

INTEN

position,isdisplayed

on

the

CRT

at

the

sweep

rate

indicated

by

the

DLY'D

SWEEP

Time/Division

switch

(see

Fig

.

2-9)

.

ENNEENEEN

Fig.2-9.(A)

INTEN

mode

display

(DL'Y TIME/DIV,

.5ms;

DLY'D

SWEEP

Time/Division,

50

)is),

(B)

Delayed

Sweep

display

.

Operating

Instructions-71353N

I



Main

SweepI

FE---

(Delay)-1.1

Time



Delayed

Sweep

Time

U

Fig.2-10

.

A

typical

mixed

sweep

display

(TIME/DIV

OR

DL'Y

TIME

setto1

ms,

DELAYED

SWEEP

Time/Division

set

to

.1

ms,

and

DELAY

TIME

MULT

dial

setto3

.55)

.

Mixed

Sweep

Operation

The

display

in

the

MIXED

position of

the

DISPLAY

MODE

switch

isafunction

of both

the

main

and

delayed

sweeps.In this

mode,

the

main sweep

is

displayed

at

the

rate

determined

by

the

TIME/DIV

OR

DL'Y

TIME

switch

followed

by

the

delayed

sweep

atarate

determined by

the

DLY'D

SWEEP

Time/Division

switch.The

amount

of

dis-

play

allocatedtoeach

sweepisdetermined

by

the

setting

of

the

DELAY

TIME

MULT

dial.A

typical

mixed sweep

dis-

playisshown

in

Fig.2-10

.

Delayed

Sweep

Triggering

A

LEVEL

control

and

SLOPE,

COUPLING,

and

SOURCE

switches

are

provided

for

delayed

sweep

trig-

gering.When

the

LEVEL

controlispressed

to

the

IN

-

RUNS

AFTER

DLY

TIME

position

the

delayed

sweep

starts

immediately

after

the

delay

time.The

delayed

sweep

LEVEL

control

and

the

SLOPE,

COUPLING,

and

SOURCE

switches

are

inoperative.This

mode

permits

the

selection

of

continuously

variable

delay times

(by

varying the

DELAY

TIME

MULTdial)

.

When

the

Delayed

Triggering

LEVEL

controlispressed

in

and

releasedtothe

OUT

-

DLY'D

SWP

TRIGGERABLE

position,

the

delayed

sweep

does

not

start at

the

com-

pletion

of

the

delay

time.Instead,itwaits

until

a

trigger

pulseisreceived

by

the

delayed

sweep

triggering

circuit

.

The

delay

time

in

this

mode

is

dependent

not

only

on

the

settings

of

the

delay-time

controls,

but

on

the

delayed

sweep

triggering

controls

and

the

occurrence

of

the

delayed

sweep

triggering

signal

as well.The

primary purpose

of

this

mode

istoeliminate

jitter

from

the

displayed

delayed-

sweep

waveform.Since

the

delayed

sweep

is

triggered

by

2-13

rotensinea

-

portion

MEN--

NEEM

ME

mmmm

no

oil

M

-

__

-

WON

EMENNEEN EMENEENN

Operating

Instructions-71353N

the

input

waveform,

jitteriseliminated

from

the

delayed

sweep

display

even

thoughitmaybe

inherent

in

the

input

waveform

.

In

the

DLY'D

SWP

TRIGGERABLE

mode

(LEVEL

control

in

OUT

position)

the

Delayed

Sweep

Triggering

LEVEL

control

and

SLOPE,

COUPLING,

and

SOURCE

switches

are

activated

.

The

Delayed

Sweep

Triggering

LEVEL

control

determines

the voltage

levelonthe

trigger

signal at

which

the

delayed

sweep

is

triggered.The

SLOPE

pushbutton

determines

whether

the

delayed

trigger

circuit

responds

on

the

positive-going

or

negative-going

portion

of

the

trigger

signal.The

selected

SLOPE

is

indicated

by

the

illuminated

portion

of the

pushbutton

.

COUPLING

and

SOURCE

lights

are

also

provided

for

delayed

triggering

.

The

positions,asmarked

on

the

pushbuttons, have

the

same

functions

for

delayed

triggering

as the

identically

marked

COUPLING

and

SOURCE

switches

for

MAIN

TRIGGERING

(see

Main

Triggering

Coupling

and

Source

discussions

given

in this

section).The

selected

Delayed

Triggering

COUPLING

and

SOURCE

positions

are

indi-

catedbyilluminated

portionsofthe

pushbuttons

.

Delayed

Gate

Output

When

the

Delayed

Triggering

SOURCE

switch

is

set

to

INT,

the

DLY'D

TRIG

IN

connector

serves

as a

Delayed

Gate

Output.The

Delayed

Gate

Outputisa

positive-going

rectangular

pulse

with

approximately

3.5volts

amplitude

.

The

pulse

width

is

coincident

with

the

time

that

the

delayed

sweep

runs

.

Therefore,

conditions

for

a

triggered

delayed

sweep,

as

described

under Delayed

Sweep

Trig-

gering

in this

section,

must

be

met

foraDelayed

Gate

Output

.

General

APPLICATIONS

The

following

information

describes

the

procedure

and

techniques

for

making

basic

measurements

witha7B53N

installedina

7000-Series

Oscilloscopq.These

applications

are

not

describedindetail,

since

each

application

must

be

adapted

to the

requirements

of the

individual

measurement

.

This

instrument

can

alsobeused

for

many

applications

not

described

in

this

manual.Contact

your

local

Tektronix

Field

Office or

representative

for

assistanceinmaking

spe-

cific

measurements

.

Also,

the

following

books

describe

oscilloscope

measurement

techniques

which

canbeadapted

for

use

with

this

instrument

:

Harley

Carter,

"An

Introduction

to the

Cathode

Ray

Oscilloscope",

Philips

Technical

Library,

Cleaver-Hume

Press

Ltd.,London,

1960

.

J.Czech,

"Oscilloscope

Measuring

Technique",

Philips

Technical

Library,

Springer-Verlag,

New

York,

1965

.

2-14

Robert

G.Middleton

andL.

Donald

Payne, "Using the

OscilloscopeinIndustrial

Electronics",

HowardW.

Sams

&

Co.Inc.,The

Bobbs-Merill

Company

Inc

.,

Indianapolis,

1961

.

John

F.Rider

and

Seymour

D.Uslan,

"Encylopedia

of

Cathode-Ray

Oscilloscopes

and

Their

Uses",

John

F.Rider

Inc.,New

York,

1959

.

JohnF.

Rider,

"Obtaining

and

Interpreting

Test

Scope

Traces",

John

F.Rider

Publisher

Inc

.,

New

York,

1959

.

Rufus

P.Turner,

"Practical

Oscilloscope

Handbook",

Volumes1and2,John

F.Rider

Publisher Inc.,New

York,

1964

.

Comparison

Measurement

Techniques

Sweep

RatesTo

establishanarbitrary

horizontal

sweep

rate

based

upon

a

specific

reference

frequency,

proceed

as

follows

:

1.Connect

the

reference

signal

to the

input of the

ver-

tical

unit.Set the

Volts/Division switch

of

the

vertical

unit

for

four

or

five

divisionsofvertical

deflection

.

2

.

Set the

TIME/DIV

OR

DL'Y

TIME

switch

and

the

VARIABLE

control so

one

cycleofthe

signal

covers an

exact

number

of

horizontal divisions.Do

not

change

the

VARIABLE

control

after

obtaining

the

desired

deflection

.

This

display

canbeusedasa

reference

for

frequency

com-

parison

measurements

.

3.To

establishanarbitrary

sweep

rate

so the

period

(time for

one

complete

cycle)ofan

unkown

signal

can

be

measured

accurately

at

any

setting

of

the

TIME/DIV

OR

DL'Y

TIME

switch,

the

period

of the reference

signal

must

be

known.If it is

not

known,

it

canbemeasured

before

the

VARIABLE

switch

is

setinstep 2

.

4.Divide

the

period

of

the reference

signal

(seconds)

by

the

productofthe

horizontal deflection

established

in

step

2

(divisions)

and

the

setting

of the

TIME/DIV

OR

DL'Y

TIME

switch.Thisisthe

horizontal

conversion

factor

:

Horizontal Conversion Factor

reference

signal

period

(seconds)

horizontal



TIME/DIV

OR

deflectionXDL'Y

TIME

(divisions)



switch

setting

5.To

measure

the period ofanunknown

signal,

discon-

nect

the

reference

signal

and

connect

the

unknown

signal

to

O

the

vertical

unit.Set

the

TIME/DIV

OR

DL'Y

TIME

switch

toasetting

that

provides

sufficient

horizontal

deflection

to

make

an

accurate

measurement.Do

not

readjust

the

VAR

(-

ABLE

control

.

6

.

Measure

the

horizontal

deflection

in

divisions

and

cal-

culate

the

period of

the

unknown

signal

using

the following

formula

:

TIME/DIV

OR



horizontal



horizontal

Period

-

DLY'

TIME

X

conversion

X

deflection

(Seconds)

switching

factor

(divisions)

NOTE

If

the

horizontal

magnifier

is

used,besure to

use

the

magnified

sweep

rate

in

placeofthe

TIME/DIV

DL'Y

TIME

switch

setting

.

Example

.

Assume

a

reference

signal

frequency

of

455

hertz

(period

2

.19

milliseconds),

a

TIME/DIV

OR

DL'Y

TIME

switch

setting

of.2ms,

and

the

VARIABLE

control

adjusted

to

provideahorizontal

deflection

of

eight

divi-

sions

.

Substituting

these

valuesinthe

horizontal

conversion

factor

formula

(step

4)

:

Horizontal

Conversion

=



=

1

.37

.2msX8

Factor

2

.19

milliseconds

Then,

with a

TIME/DIV

OR

DL'Y

TIME

switch

setting

of

50

ps,

the periodofan

unknown

signal

which

completes

one

cycleinseven

horizontal

divisions

can

be

determined

by

using

the

period

formula

(step6):

Period

-

(Seconds)



50psX

1

.37X7 =

480

ps

This

answer

can be

converted

to

frequencybytaking

the

reciprocal

of

the period

in

seconds

(see

application

on

Determining

Frequency

Measurements)

.

Time

Duration

Measurements

To

measure

time

between

two

pointsona

waveform,

use

the

following

procedure

:

1

.

Connect

the

signal

tobedisplayed

to

the

inputofthe

vertical

unit

.

2.Set the

Vertical

and

Horizontal

Mode

switches

on

the

indicator

oscilloscope

to

display

the

plug-in

units

used

.

Operating

Instructions-71353N

3.Set

the

Volts/Division

switch

of

the

vertical

unit

to

display

about

four

divisions

of

waveform

.

4.Set

the

MAIN

TRIGGERING

controls to

obtain

a

stable

display

.

5

.

Set the

TIME/DIV

OR

DL'Y

TIME

switch to

the

fastest

sweep

rate

that

displays

less

than

eight

divisions

be-

tween

the

time

measurement

points

(see

topic

entitled

Time

Measurements

and

Fig

.

2-7)

.

6.Adjust

the

vertical

unit

position

controltomove

the

points

between

which

the

time

measurement

is

made

to

the

center horizontal

line

.

7.Adjust

the

horizontal

POSITION

control

to position

the

time-measurement

points

within the

center

eight

divi-

sionsofthe

graticule

.

8.Measure

the

horizontal

distance

between

the

time

measurement

points.Be

sure

the

VARIABLE

controlisset

to

CAL

.

9

.

Multiply

the

distance

measured

in

step8by

the

set-

tingofthe

TIME/DIV

OR

DL'Y

TIME

switch

.

If

sweep

magnification

is

used,

divide

this

answer by10.

Example.Assume

that

the

distance

between

the

time

measurement

points

is

five

divisions

(see

Fig.2-11),

and

the

TIME/DIV

OR

DL'Y

TIME

switch

is

setto.1ms.

Fig.2-11

.

Measuring

the

time

duration

between

pointsona

wave-

form

.

2-15

Operating

Instructions-71353N

Using

the

formula

:

Time

Duration

Time

Duration

=

Substituting

the

given

values

:

The

time

durationis0

.5

millisecond

.

Determining

Frequency

Use

the

following

procedure

:

horizontal



TIME/DIV

OR

distanceX



DL'Y

TIME

(divisions)

setting

magnification

5X0.1ms

1

The

time

measurement

technique

can

also

be used to

determine

the

frequencyofa

signal.The

frequencyofa

periodically

recurrent

signalisthe

reciprocalofthe

time

duration

(period)ofone

complete

cycle

.

1.Measure

the

time duration

of

one

complete

cycle

of

the

waveformasdescribedinthe

.

2.Take

the

reciprocalofthe

time

durationtodetermine

the

frequency

.

Example

.

The

frequencyofthe

signal

showninFig.2-11

which

hasatime

periodof0.5millisecondis:

1



1

Frequency

=

time

period0.5

millisecond=

2

kilohertz

Risetime

Measurements

Risetime

measurements

employ

basically

the

same

tech-

niquesastime-duration

measurements.The

main

difference

is

the

points

between

which

the

measurementismade

.

The

following

procedure

gives

the

basic

method

of

measuring

risetime

between

the

10%

and

90%

pointsofthe

waveform

.

Falltime

can

be measured

in

the

same

manner

on

the

trail-

ing

edgeofthe

waveform

.

1 .

Connect

the

signal

to be

displayedtothe

inputofthe

vertical

unit

.

2-16

2.Set

the

Vertical

and

Horizontal

Mode

switchesonthe

indicator oscilloscopetodisplay

the

plug-in'unit

used

.

3.Set

the

Volts/Division

switch

and

the

Variable

Volts/

Division

controlofthe

vertical

unittoproduceasignal

an

exact

numberofdivisionsinamplitude

.

4.Center

the

display

about

the center

horizontal

line

with

the

vertical

unit Position

control

.

5.Set

the

MAIN

TRIGGERING

controls to

obtain

a

stable

display

.

6.Set the

TIME/DIV

OR

DL'Y

TIME

switch

to

the

fastest

sweep

rate

that

displays

less

than

eight

divisions

be-

tween

the

10%

and

90%

pointsonthe

waveform

.

7

.

Determine

the

10%

and

90%

pointsonthe

rising

portionofthe

waveform

.

The

figures

given

in

Table

2-1 are

for

the

points

10%upfrom

the

startofthe

rising

portion

and

10%

down

from the

topofthe

rising

portion

(90%

point)

.

TABLE

2-1

Risetime

Measurements

8.Adjust

the

horizontal

POSITION

controltomove

the

10%

pointofthe

waveform

to

the

second

vertical

line

of

the

graticule

.

For example,

withafive-division

display

as

shown

in

Fig.2-12,

the

10%

pointis0.5divisionupfrom

the

startofthe

rising

portion

.

9.Measure

the

horizontal

distance

between

the

10%

and

90%

points.Be

sure

the

VARIABLE

control

is

settoCAL

.

10.Multiply

the

distance

measured

in

step9by

the

setting

of

the

TIME/DIV

OR

DL'Y

TIME

switch.If

sweep

magnificationisused,

divide

this

answer by 10

.

O

Divisions

vertically

Vertical

between

display

10%

and

90%

10%

and

90%

(divisions)

points

4

0

.4

and3.6

divisions

3

.2

5

0.5and4.5

divisions

4

.0

6

0.6and5.4

divisions

4

.8

7

0

.7

and5.4

divisions

5

.6

8

0.8and7.2

divisions

I

6.4

Fig.2-12.Measuring

risetime

.

Example

.

Assume

that

the horizontal

distance

between

the

10%

and

90%

pointsisfour

divisions

(see

Fig.2-12)

and

the

TIME/DIV

OR

DL'Y

TIME

switchissetto1 Its

with

the

MAG

switch

settoX10.Applying

the

time

duration

formulatorisetime

:

horizontal



TIME/DIV

OR

Time

Duration

=



distance



DL'Y

TIME

(Risetime)

(divisions)

setting

magnification

Substitute

the

given

values

:

Risetime

= 4

X1microsecond

The

risetimeis0.4microsecond

.

Delayed

Sweep

Measurements

The

delayed

sweep

mode

canbeusedtomake

accurate

time

measurements.The

following

measurement

determines

the

time

difference

between

two

pulses

displayed

on

the

same

trace.This

application

may

alsobeusedtomeasure

time

difference

from

two

different

sources

(dual-trace)

or

to

measure

time duration

of

a

single

pulse.See

Section

1

for

measurement

accuracy

.

1.Connect

the

signaltobe

displayed

to the

input

of the

vertical

unit

.

2.Set

the

vertical

and

horizontal

Mode

switchesonthe

indicator oscilloscope

to

display the

plug-in

units

used

.

3.Set the

Volts/Division

switch of the

vertical

unit to

produce

a display

about4divisionsinamplitude

.

4.Adjust

the

MAIN

TRIGGERING

controls

forastable

display

.

Operating

Instructions-7B53N

5.If

possible,

set

the

TIME/DIV

OR

DL'Y

TIME

switch

toasweep

rate

which

displays

about

eight

divisions

be-

tween

pulses

.

6.Press

the

INTEN

pushbutton

of the

DISPLAY

MODE

switch

and

press the

Delayed

Triggering

LEVEL

control to

theIN-

RUNS

AFTER

DL'Y

TIME

position

.

7.Set the

DLY'D

SWEEP

Time/Division

switch

to

a

setting

1/100ofthe

TIME/DIV

OR

DL'Y

TIME

sweep

rate

.

This

produces

an

intensified

portion

approximately0.1

di-

vision

in

length

.

NOTE

Measurement

accuracy

willbeaffectedifthe

LEVEL

control

setting

for

MAIN

TRIGGERING

or the

hori-

zontal

POSITION

control

settingischanged

.

8.Rotate the

DELAY

TIME

MULT

dial

to

move

the

intensified

portion of the

trace

to the

first

pulse

.

9.Press

the

DLY'D

SWP

pushbutton

of the

DISPLAY

MODE

switch

.

10.Adjust

the

DELAY

TIME

MULT

dial

to

move

the

pulse

(or

the

rising

portion)tothe center

vertical

graticule

line.Note

the

exact

setting

of the

dials

.

11.Turn

the

DELAY

TIME

MULT

dial

clockwise

until

the

second

pulseispositioned

to the

same

pointasthe

first

pulse.(If

several

pulses

are

displayed, returntothe

INTEN

positionofthe

DISPLAY

MODE

switchtolocate

the

cor-

rect

pulse).Again

note

the

exact

dial

setting

.

12.Subtract

the

first

dial

setting

from

the second

and

multiply

by

the

delay

time

shown

by

the

TIME/DIV

OR

DL'Y

TIME

switch.This

figureisthe

time

interval

between

pulses

.

Example.Assume

the

first

dial

setting

is 1

.31

and

the

second

dial

settingis8

.81

with

the

TIME/DIV

OR

DL'Y

TIME

switch

setto0.2microsecond

(see

Fig.2-13)

.

Time

Difference



__

(Delayed

Sweep)

(second

dial

setting-first

dial setting)

X

Substituting the

given

values

:

Time

Difference=(8

.81-1

.31)X0.2!ts

The

time

differenceis1.5ps

delay

time

(TIME/DIV

OR

DL'Y

TIME

switch

setting)

2-17

RPM

MEMONE

t I

jam-

Horizontal

distance

}i

11

MMMOMMMMMM

(A)

Intensified

sweep

display

.

(B)

Delayed

sweep

display

.

Fig.2-13

.

Measuring

time

difference using

delayed

sweep

.

Delayed

Sweep

Magnification

The

delayed

sweep

feature

of

the

7B53N

can be

used

to

provide

higher

apparent

magnification

than

is

provided

by

the

MAG

switch.The

sweep

rate

of

the

delayed

sweep

is

not

actually

increased

;

the

apparent

magnificationisthe

resultofdelaying

the

Delayed

Sweep

an

amountoftime

selected

by

the

TIME/DIV

OR

DL'Y

TIME

switch

and

the

DELAY

TIME

MULT

dial

before

the

display

is

presented

at

the

sweep

rate

selected

by

the

DLY'D

SWEEP

Time/

Division switch

.

The

following

method

uses

the

IN-RUNS

AFTER

DL'Y

TIME

Delayed

Trigger

Mode

to

allow

the

delayed

portion

of

the

display

to be

positioned

with

the

DELAY

TIME

MULT

dial

.Ifthereistoo

much

jitter

in

the

delayed

sweep

display,

use

the

Triggered

Delayed

Sweep

Magnification

procedure

which

follows

this

procedure

.

1

.

Connect

the

signal

tobedisplayed

to

the

input

con-

nector of

the

vertical

unit.Set

the

Vertical

and

Horizontal

Mode

switches

on

the

indicator

oscilloscope

to

display

the

plug-in

units

used

.

2-

1

8

4.Set

the

TIME/DIV

OR

DL'Y

TIME

switch to

a

sweep

rate

which

displays

the

complete

waveform

(see

Fig

.

2-14A)

.

5.Press

the

INTEN

pushbuttonofthe

DISPLAY

MODE

switch

and

press

the

Delayed

Trigger

LEVEL

control

to

IN-RUNS

AFTER

DL'Y

TIME

.

6.Position

the

startofthe

intensified

portion

with

the

DELAY

TIME

MULT

dialtothe

partofthe

displaytobe

magnified

.

71-

1

(A)

Main

sweep

display

.

(B)

Delayed

sweep

display

.

Pulsetobe

magnified

MOMMMON

ME

amm

I

Fig.2-14

.

Using

delayed

sweep

for

magnification

.

Operating

Instructions-712153N

2.Set

the

Volts/Division

switch

of

the

vertical

unit

to

DELAY-TIME

MOLT

dial

:

produce

a

display

about

4

divisionsinamplitude

.

MOLT

dial

:

1

.31

8

.81

1

MINE

WOMEN

HNIN

3.Adjust

the

MAIN

TRIGGERING

controls

forastable

display

.

EKE

7.Set the

DLY'D

SWEEP

Time/Division

switchtoa

setting

which

intensifies

the

full

portionofthe

display

to

be

magnified

.

The

startofthe

intensified

trace

will

remain

as

positionedinStep6.

8.Press

the

DISPLAY

MODE

switchtoDLY'D

sweep

.

9

.

Time

measurements

canbemade

from

the

display

in

the

conventional

manner

.

Sweep

rateisdeterminedbyset-

tingofthe

DLY'D

SWEEP

Time/Division

switch

.

10.The

apparent

sweep

magnification

can be

calculated

by

dividing

the

TIME/DIV

OR

DL'Y

TIME

switch

setting

by

the

DLY'D

SWEEP

Time/Division

switch

setting

.

Example.The

apparent

magnificationofthe

display

shown

in

Fig.2-14

with a

TIME/DIV

OR

DL'Y

TIME

settingof.1msandaDLY'D

SWEEP

Time/Division

switch

settingof1

microsecond

is

:

Apparent

Magnification

=

TIME/DIV

OR

DL'Y

TIME

setting

DLY'D

SWEEP

Time

Division

setting

Substituting

the

given

values

:

Apparent



=

1

X

10-4

Magnification



1

X~

10Z-

The

apparent

magnificationis100

times

.

Triggered

Delayed

Sweep

Magnification

The

delayed

sweep

magnification

method

just

described

may

produce too

much

jitterathigh

apparent

magnifi-

cation ranges

.

The

OUT-DLY'D

SWP

TRIGGERABLE

mode

providesamore

stable

display,

since

the

delayed

sweep

displayistriggeredatthe

same

point

each

time

.

1.Setupthe

displayasgiveninsteps1through 7inthe

Delayed

Sweep

Magnification

procedure

.

2.Pressinand

release

the Delayed

Triggering

LEVEL

controltothe

OUT-DLY'D

SWP

TRIGGERABLE

posi-

tion.Select

the

desired

Delayed

Triggering

SLOPE,

COUPL-

ING,

and

SOURCE

.

3.Adjust

the

Delayed

Triggering

LEVEL

controltopro-

duce an

intensified

portiononthe

display

.

4.Inabilitytoproduceanintensified

zoneonthe

dis-

play

indicates

that

the Delayed

Triggering

controls

are

Operating

Instructions-71353N

incorrectly

set,orthat

the

signal

does not

meet

triggering

requirements

.

If

the

condition

cannotberemedied

with

the

Delayed

Triggering controls or

by

increasing

the

display

amplitude

(lower Volts/Division

setting),

externally

trigger

the

delayed

sweep

.

5.When

the

correct

portionofthe

displayisintensified,

set

the

DISPLAY

MODE

switch to

DLY'D

SWP.Slight

re-

adjustmentofthe

Delayed

Triggering

LEVEL

control

may

be

necessary

to

produce

a

stable

display

.

6.Measurement

and

magnification

areasdescribed

aboveinDelayed

Sweep

Magnification

discussion

.

Displaying

Complex

Signals

Using

Delayed

Sweep

Complex

signals

often

consist

of

a

numberofindividual

events of

differing

amplitudes.Since

the

trigger

circuits

are

sensitivetochangesinsignal

amplitude,astable

display

can

normallybeobtained only

when

the

sweepistriggered

by

the

event(s)

having the

greatest

amplitude.However,

this

may

not

produce

the

desired displayofa

lower-amplitude

portion

which

follows

the

triggering

event.The

delayed

sweep

feature

provides

a

meansofdelaying

the

startofthe

delayed

sweep

byaselected

amount

following the

event

which

triggers

the

Main

Sweep

Generator.Then, the

part

of

the

waveform

which

contains

the

informationofinterest

can be

displayedatthe

delayed

sweep

rate

.

Use

the following

procedure

:

1 .

Set

up

the

displayasgiveninSteps1through8of

Delayed

Sweep

Magnification

.

2.Time

measurements

can be

made

from

the

display

in

the

conventional

manner.Sweep

rateisdetermined by

the

settingofthe

DLY'D

SWEEP

Time/Division

switch

.

Example

:Fig.2-15

showsacomplex

waveformasdis-

playedonthe

CRT.The

circled

portionofthe

waveform

cannotbeviewedinany

greater

detail

because

the

sweep

is

triggeredbythe

larger

amplitude

pulses at

the

startofthe

display

andafaster

sweep

rate

moves

this

area

of

the

wave-

form

off

the

viewing

area.The

second

waveform

shows

the

area

of

interest

magnified

10 times

using

Delayed

Sweep

.

The

DELAY

TIME

MULT

dial

hasbeen

adjusted so

the de-

layed

sweep

starts

just

before

the

area of

interst

.

Pulse

Jitter

Measurements

In

some

applications

it is

necessarytomeasure

the

amount

of

jitteronthe

leading

edgeofa

pulseorjitter

between

pulses

.

2-19

Operating

Instructions-71353N

(A)

This portionofdisplay

cannot be viewed

adequately

be-

cause

the

main

sweep

is

triggeredonlarger

amplitude

signals

at

the

startofdisplay

.

NEENEENEEN NEEMEMENNN NESPEENNEN

"

EMEMEMEN

"

MENNEENEEN

ENEENEEMEN

(B)

Areaofinterest

displayedbydelaying

the

main

sweep

(DLY'D

SWP

mode)

.

Fig.2-15.Displaying

a

complex

signal

using

delayed

sweep

.

1.Connect

the

signaltobe

displayedtothe

input

con-

nectorofthe

vertical

unit.Set

the

Vertical

and

Horizontal

Mode

switches

on

the

indicator oscilloscope

to

display

the

plug-in

units

used

.

2.Set the

Volts/Division

switchofthe

vertical

unit

to

produceadisplay

about

4

divisionsinamplitude

.

3.Adjust

the

MAIN

TRIGGERING

controls

forastable

display

.

4.Set the

TIME/DIV

OR

DL'Y

TIME

switchtoa

sweep

rate

which

displays

the complete

waveform

(see

Fig

.

2-14A)

.

5.Press

the

INTEN

pushbuttonofthe

DISPLAY

MODE

switch

.

Press

and

release

the Delayed

Triggering

LEVEL

controltoOUT-DLY'D

SWP

TRIGGERABLE,

and

adjust

the

LEVEL

control

forastable

intensified

display

.

2-

20

6

.

Position

the

start

of

the

intensified

portion

with

the

DELAY

TIME

MULT

dialtothe

part of

the

display

to be

magnified

.

7.Set the

DLY'D

SWEEP

Time/Division

switch

to

a

setting

which

intensifies

the

full

portionofthe

display

to

be

magnified.The

startofthe

intensified

trace

will

remain

as

positionedinStep 6

.

8

.

Press

the

DISPLAY

MODE

switch

to

DLY'D

SWP

.

9.Slight

readjustment

of

the

Delayed

Triggering

LEVEL

control

maybenecessarytoproduceasstable

dis-

playaspossible

.

10

.

Pulse

jitterisshownbyhorizontal

movement

on

the

pulse

(take

into

account

inherent

jitter

of

Delayed Sweep)

.

Measure

the

amount

of

horizontal

movement.Be

sure that

both

vertical

and

horizontal

VARIABLE

controls

are

set

to

CAL

.

11.Multiply

the

distance

measuredinStep 10

by

the

DLY'D

SWEEP

Time/Div

switch

setting

to

obtain

pulse

fit-

terintime

.

Example.Assume

that

the

horizontal

movementis0

.5

division

(see

Fig.2-16)

and

the

DLY'D

SWEEP

Time/

Division

switchis.5

microsecond

.

Using

the

formula

:

horizontal



DLY'D

SWEEP

Pulse

Jitter=jitter

X

Time/Division

(division)

setting

Substituting

the

given

values:Pulse

Jitter=0.5X0.5

microsecond

The

pulse

jitteris0

.25

microsecond

.

MMMMMMMMMM MMMMMr=M== MMMMMIJIMMMM MMMMMI

MMMM! MMMMMAMMMM MMMMEMMMM

MENEAMMEN

EMENEREENE

I

Jitter

.mod

1

.0-

Fig.2-16.Measuring

pulse

jitter

.

Introduction

SECTION

3

CIRCUIT

DESCRIPTION

This

section

of

the

manual

contains

a

descriptionofthe

circuitry

usedinthe

7B53N

Dual

Time

Base.The

descrip-

tion

begins

withadiscussion

of

the

major

circuit

functions

usingasimplified

block

diagram

.

SIMPLIFIED

BLOCK

DIAGRAM

The

Simplified

Block

Diagram,

Fig.3-1,

shows

intercon-

nectionofthe

basic

circuit

blocksinthe

7B53N

.

In

some

cases,

suchasthe

Main

Sweep

Trigger,

the

block

includes

a

number

of

separate

circuits.The

individual

circuits

are

dis-

cussed

in

detail

later

in this

section

.

Main

Sweep

Mode

When

the

DISPLAY

MODE

switchissettoselect

MAIN

SWP,

operationisas

follows

:

Main

Sweep

Trigger.This

block

includes

circuitry

for

selecting

the

trigger

source,

type

of

coupling,

triggering

mode,

and

point

on

the

trigger

signal

where

triggering

oc-

curs.Also,

regardlessofthe

trigger

signal

shape

or ampli-

tude

(within

specification),

this

circuitry

providesafast-

rise,

uniform-amplitude

pulsetothe

Main

Sweep

Start

Multi

.

Terminationofthe

pulse

(or

gate)

occursatthe

rise

of

Main

Sweep

Holdoff

.

Main

Sweep

Start

Comparator.This

circuitisactivated

by

the

positive

gate

from

the

Main

Sweep

Trigger.The

output

signal

coupledtothe

Main

Sawtooth

Generatorisa

positive gate

with

the

same

durationasthe

sweep

.

This gate

is

also

coupled

to

the

Sweep

Gate

Out

.

A

negative-going

gate

(coincident

with

the

positive

gate)

is

coupledtothe

Delayed

Sweep

Lockout

Multi

and

the

Delayed

Sweep

Start

Control

.

Main

Sawtooth

Generator

.

The

main

sweep

signalisde-

velopedbythe

Main

Sawtooth

Generator.Whenapositive

gate

from

the

Main

Sweep

Start

Multiisapplied,

a

sawtooth

waveform

is

generated

.

The

sawtooth

durationisdeter-

minedbythe

positive

gate

duration.Rateofchange

of

the

sawtooth

is

set

by Ct and

Rt,

selected

by

the

TIME/DIV

switch

.

Delayed

Sweep

Mode

7B53N

Sweep

Stop

Comparator

.

One

sideofthis

comparator

is

drivenbythe

main

sweep

sawtooth

signal,

and the

other

sideissetbythe

Main

Swp

Stop

adjustment

.

When

the

sawtooth

waveform

passes

through

the

settingofthe

Main

Swp

Stop

adjustment,

the

output

of

the

Sweep

Stop

Com-

parator

switchestoa

positive

level.This

positive step

is

applied

to

the

Main

Sweep

Holdoff and

by

wayofa

small

capacitancetothe

Main

Sweep

Start

Multi.This

resets

the

Main

Sweep

Start Multisothat

it is

readytoreceive

another

trigger

signal

.

Main

Sweep

Holdoff.This

circuit

developsagate

which

is

usedtoprevent

generation

ofatrigger

signal until

the

sweep

circuits

have

stabilized

afterasweep

.

The

positive

step

from

the

Sweep

Stop

Comparator

initiates

the

positive

holdoff

gate.The

durationofthe

holdoff

gate

is

variable,

depending

on

the

settingofthe

TIME/DIV

switch.Holdoff

timing

capacitors

are

separate

trom

sweep

timing

capacitors.Holdoffislonger

for

slower

sweep

rates

.

Output

from

the

Main

Sweep

Holdoff

is

coupledtothe

Main

Sweep

Trigger

and the Delayed

Sweep

Trigger.A

trig-

ger

signal

cannotbegenerated

during the

holdoff

interval

.

The

holdoff

servestoreset

the

trigger circuits

so that

they

are

readytoreceiveaninput

trigger

signal

after

holdoff

.

Horiz

Output.The

Horiz

Output

block

includes

the

Ext

Horiz

Amp,

Position

Amp,

Horiz

Display

Selector,

and

Horiz

Out

Amp

circuits

.

With the

DISPLAY

MODE

switch

settoMAIN

SWP,

this

circuit selects

the

signal

from

the

Main

Sawtooth

Gener-

ator,

amplifies

the

signal,

and

converts

the

single-ended

inputtoa

push-pull

output

signal.A

DC

positioning

level

is

also

applied

to

this

block

.

To

generate

the

delayed

sweep,

the

Main

Sawtooth

Gen-

erator

must

first

be

gatedon(see

Main

Sweep Mode)

.

Delay

Pickoff.This

circuit

suppliesapositive gate

which

starts

when

the

main

sawtooth

signal

passes

through

the

level

selected

by

the

DELAY

TIME

MULT

control.The

gate

ends

with

the

main

sawtooth

signal.The

output

signal

is

coupled

to

the Delayed

Sweep

Trigger

.

INT

Fig.3-

1 .

7B53N

Simplified

Block

Diagram

.

Delayed

Sweep

Trigger

.

When

the

Delayed

Trigger

LEVEL

is

pushed

in,

the

output

triggerisgeneratedassoon

as

the

Delay

Gate

signalisapplied.If

the

LEVEL

control

is

out,

the

output

trigger

is

initiatedbythe

trigger

after

the

Delay Gateisapplied

.

The

Delayed

Sweep

Trigger

outputisa

positive gate

whichisterminated

by

the

Holdoff

signal

and/or

the

pos-

itive

step

from

the

Delayed

Sweep

Stop

circuit.The

pos-

itive

output

gateiscoupled

to

the

Delayed

Sweep

Start

Multi

.

Delayed

Sweep

Start

Multi.The

signal

from

the

Delayed

Sweep

Trigger

causes the

Delayed

Sweep

Start

Multitoflip

so

that

a

positive

gateiscoupled

to

the

Delayed

Sweep

Start

Control,

andanegative

gateisappliedtothe

Mixed

Sweep

Comparator

.

The

output

gates

are

the

same

in

dura-

tionasthe

positive

gate

from

the Delayed

Sweep

Trigger

.

Delayed

Sweep

Start

Control

.

For

DLY'D

SWP

mode

of

operation

the

Delayed

Sweep

Start

Control

servestocouple

the

positive gate

from

the

Delayed

Sweep

Start

Multitothe

Delayed

Sawtooth

Generator and

the

Sweep

Gate

Out

.

Input

signals

from

the

Main

Sweep

Start

Multi

and

the

Delayed

Sweep

Lockout

Multi

are

not

effective

in this

mode

.

Delayed

Sawtooth

Generator

.

The

delayed

sweep

signal

is

developed

by the

Delayed

Sawtooth

Generator.The

saw-

toothisgenerated

during

the

time

thatapositive

gate

is

applied

from

the

Delayed

Sweep

Start

Control.Rate

of

changeofthe

sawtoothisset

by Ct

and

Rt,

selectedbythe

TIME/DIV

(Dly'd)

switch

.

The

sawtooth

output

signaliscoupled

to

the

Mixed

Sweep

Comparator

and

the

Horiz

Output

circuits

.

Delayed

Sweep

Stop

Circuit

.

A

positive step

occurs

at

the

outputofthe

Delayed

Sweep

Stop

circuit

when

the

delayed

sawtooth

passes

through

the

level

selectedbythe

Dly'd

Swp

Length

adjustment.This

stepiscoupledtothe

Delayed

Sweep

Trigger

and the Delayed

Sweep

Lockout

Multi

.

Mixed

Sweep

Mode

In this

modeofoperation,

the

sweepisfirst

running

at

the

MAIN

SWP

rate

and

then,

after

the

selected

delay

in-

terval,

runsatthe

DLY'D

SWP

rate.The

main

sweep

and

delayed

sweep

are

initiated

as previously

described

.

Oper-

ationofother

circuit

blocks

follows

.

External

Horiz

Input

General

CIRCUIT

OPERATION

Circuit

Description-71353N

Mixed

Sweep

Comparator.This

circuit

determines

which sweep

signaliscoupledtothe

Horiz

Output

stage

.

First,

the

main

sweep

sawtooth

is

coupled through

the

Mixed

Sweep

Comparator

and

the

Delayed

Sawtooth

Gen-

eratortothe

Horiz

Output

stage.These

stages

perform

as

an

operational

amplifier

during the

time

that

the

main

sweep

is

being

displayed

.

When

a

positive

gate

from

the

Delayed

Sweep

Trigger

is

appliedtothe Delayed

Sweep

Start

Multi,anegative

gate

is

generated

and coupled

to

the

Mixed

Sweep

Comparator

.

This

opens the

Mixed

Sweep

Comparator

circuit,

preventing

the

main

sweep

sawtooth

from

being

coupled

to

the

Horiz

Output

circuit

.

Simultaneously,

the

positive

gate

from

the

Delayed

Sweep

Start

Multi

is

coupled through

the

Delayed

Sweep

Start

Control

to

the

Delayed

Sawtooth

Generator.The

de-

layed

sweep

sawtoothisgenerated

and

coupled

to

the

Horiz

Output

stage

.

Delayed

Sweep

Lockout

Multi.The

positive

step

from

the

Delayed

Sweep

Stop

circuitisinverted

by

the

Delayed

Sweep

Lockout

Multi

and coupledtothe

Delayed

Sweep

Start

Control,

thus

turning

off

the

Delayed

Sawtooth

Gen-

erator

.

Sweep

Gate

Out

.

Depending

on the

selection

of

the

DISPLAY

MODE

switch,

this

stage

couples

the

positive

gate

from

either

the

Main

Sweep

Start

Multi

or

the

Delayed

Sweep

Start

ControltoconnectorAl.

The

Sweep

Gate

signal

servestounblank

the

CRT

in

the

Indicator

Oscillo-

scope

during the

sweep

.

When

the

TIME/DIV

switch

is

settoAMPL,

partofthe

Main

Sweep

Trigger

circuitry

becomes

the

Horiz Input

Amp.An

external

signal

connectedtothe

MAIN

TRIG

IN

or

AMPL

input

is

amplified

and

then

coupled

to

the

Horiz

Output

stage

.

The

main and

delayed

sawtooth

generators

are

disabled to

prevent

intensity

modulationofthe

CRT

tracebythe

unblanking

waveforms

.

This

section

provides

a

detailed

descriptionofthe

elec-

trical

operation

and

relationshipofthe

circuits

in

the

7B53N

.

The

theoryofoperation

for

circuits

unique

to this

instrumentisdescribed

in

detailinthis

discussion.Circuits

which

are

commonly

usedinthe

electronics

industry

are

not

describedindetail.If

more

information

is

desired

on

these

commonly

used

circuits,

refertothe

following

text-

books

.

3-3

Circuit

Description-71353N

Tektronix

Circuit

Concepts

Books

(order

from

your

local

Tektronix

Field

Office or

representative)

.

Horizontal

Amplifier

Circuits,

Tektronix

PartNo.

062-1144-00

.

Oscilloscope Trigger

Circuits,

Tektronix

Part

No

.

062-1056-00

.

Sweep

Generator

Circuits,

Tektronix

PartNo.

062-1098-01

.

Phillip

Cutler,

"Semiconductor

Circuit

Analysis,'

McGraw-

Hill,

New

York,

1964

.

Lloyd P

.

Hunter (Ed

.),

"Handbook

of

Semiconductor

Electronics,"

second

edition,

McGraw-Hill,

New

York,

1962

.

Jacob

Millman

and

Herbert

Taub,

"Pulse,

Digital,

and

Switching

Waveforms,"

McGraw-Hill,

New

York,

1965

.

The

main

headings

in this

circuit

analysis

refertosche-

maticsinthe

diagrams

section

with

the

same name.The

sub-headings

indicate

the

individual

circuit

being described

.

The

main

block

diagraminthe

last

sectionofthe

manual

shows

interconnection

between

circuits

.

MAIN TRIGGER

PREAMP

The

Main

Trigger

Preamp

selects trigger

source

and

coupling

for

the

Main

Trigger

Generator

and

provides

am-

plification

for

external horizontal

signals

when

the

TIME/

DIV

OR

DL'Y

TIME

switchissettoAMPL

.

This

circuit

consists

of four

stages:Trigger

Source

Switching, External

Trigger

Preamp

or External

Input

Am-

plifier,

Balanced-to-Single-Ended

Converter,

and

Trigger

Coupling.Fig.3-2

showsadetailed

block diagramofthe

Main

Trigger

Generator

circuit

and the

schematicofthis

circuitisshown

on diagram1at

the

rearofthis

manual

.

Trigger

Source

Switching

U330

receives

trigger

inputs at

pins2and15for

internal

triggering

andatpin7for

external

trigger signals.Pin4of

U330

determines

which

input

signalisselectedbymeans

of

J16

MAIN TRIG

IN or

AMPL

EXT-10

Line

Trigger

Signal

from

-0

0

Main

Frame

S7

IJV

RCE

SOU

f1W

T

Internal

Trig

.

_±__~

ger

Signal

from

Vertical

Unit

S6

COUPLING

Balanced-to- Single-Ended

Converter 0352,

12354,

0358

To

Slope

Selector and

Level

\

Comparator

01

Trigger Coupling 0362,

12364

12366

3-4

Fig,

3-2.Main

Trigger

Preamp

detailed

block

diagram

.

External

Trigger

Preamp

or

Horizontal

Input

Am-

plifier

SOURCE

switchS7at

the

input

selects internal,

ex-

ternal,orline

signals

for

triggering.The

external

trigger

(or

horizontal

input)

signal

may

be

attenuated

to

one-tenth

amplitudebyselecting

EXT-10

.

R13

and

R14

(paralleled

by

R302)

forma10:1attenuator

.

The

input

impedance

for

the

trigger

(or amplifier)

input

is1megohm,

consisting

primarilyofR5

and

R302.This

resistor

pair

also

causes

a2Xattenuationofthe

input

signal

as

seenatthe

gateofQ308

.

C301

compensates

the

input

stage

and

C10

compensates

the

10X

attenuator

.

CR303

and

CR305

protect

Q308

from

excessive

input

signalbyclamping

the

gateifthe

signal at

the

input

con-

nector

exceeds

approximately+or-2.5

volts.The

signal at

the sourceofQ308iscoupled through

emitter-followers

0312

and

Q316

to

pin7of

U330.The

signal at

7

of

U330isterminatedinapproximately50ohms

by

R319

to

preserve

the

high-frequency

characteristics

.

a

digital signal

(voltage

level).A

Low

Levelatpin4acti-

vates

pins2and 15

for

internal

triggering,

whileahigh

level

on

4

switches

U330

to

activate pins7and10for

ex-

ternal

triggering

.

To

further

examine

U330,

assume

that

pin4is

low,

activating

pins

2 and 15

(internal

triggering).This

input

is

a

relatively

high

impedance

differential

configuration.Pin

15

receives

the

positive-going

trigger

signal

and

pin2is

the

negative-going

input.The

inputs

are

biasedatthe

center

of

their

dynamic

range,

and

signal-limitinginthe

trigger

pick-

off

circuitry

(in

the

indicator

oscilloscope)

assures

that

the

inputs

will

not be

driven

into

either

cutofforsaturation

.

R336

and

R337

terminate

the

internal trigger

signal

from

the

indicator oscilloscope.The

current

source for

internal

triggeringisby

wayofPins1and16and

R343

.

The

output

current

appears

at pins12and13.

A

positive-going

signal at

pin15causes an

increase

in

current

into

pin13and

out

through

16,

R341

and

R343

.

Si-

multaneously,

the

negative-going

signalatpin2causes

a

decreaseincurrent

into

pin12and

out through

1,

R342,

and

R343

.

The

net

resultisthat

the

total

current

through

pins 12

and13and

R343

remains

constant

.

The

current

source

for

external

triggeringisby

way

of

pins8and9and

R346.Operationisthe

sameasinternal

triggering

.

Circuit

Description-71353N

R330

sets

theDClevelatpin

10ofU330,

whichisthe

negative

sideofthe

external

trigger

differential

input.This

matches

the

DC

balanceofthe

external

trigger

input

of

U330

to that

of the

internal

trigger

input

.

Balanced-to-Single-Ended

Converter

The

balancedtosingle-ended

converter

changes

the

out-

putofU330toa

single-ended

signal at

the

emitterofQ358

.

The

trigger signal

through

U330

causesadecreaseincurrent

into

12

from

R350

and

R354

andanincreaseincurrent

into

pin13from

R351.This

would

normally

cause

the

voltageatpin

12toswing

in

a

positive

direction,

while

13

goes

inanegative

direction.However,

the

current

through

R350

and

R354

actually

increases

duetothe

feed-

back

via

R355

and

Q354,

causing

the

voltageatpin12to

swing

negative

along

with

pin13.

Q354isconnectedasa

diode

andisenclosedinthe

same

heat-sink

with

Q352,

providing

good

DC

stability.The

DC

Balance

adjustment

R350

sets

the

quiescentDClevelofthe

BalancedtoSingle

Ended

Converter

to

zero

volts

allowing

theDClevelatthe

outputtocorrespondtotheDClevel

at

the

input

.

Trigger

Coupling

When

DC

coupling

is

selected

by the

front-panel

COUPLING

switch,

Q362

is

turned

on by

the

+15

volts

supply through

R18,

S6,

and

R361.The

triggering

signal

is

then

coupled through

R359

and

Q362

to

the

baseofQ402

(on Main

Trigger

Generator

diagram)

.

Q364isturnedonwhen

AC

couplingisselected

.

The

triggering

signal

then

passes

through

Q364

and

C364tothe

base of

Q402.For

AC

LF

REJ

coupling,

Q364isoff

and

the

triggering

signaliscoupled through

C362

and

C364,

attenuating

low-frequency

signals

.

For

AC

HF

REJ

coupling,

both

Q364

and

Q366

are

turnedon.

The

high-frequency

components

are

coupled

through

C367

and

Q366

to

ground,

while

the

desired

trig-

gering

componentiscoupled through

Q364

and

C364

(as

in

AC

coupling)

.

MAIN

TRIGGER

GENERATOR

The

Main

Trigger

Generator

provides

selection

of

the

level

and

slope

where

triggering

occurs

and

suppliesafast-

rise

uniform-amplitude

pulsetothe

Main

Sweep

Start

Multi

.

The

Main

Trigger

Generator

includes

the

Level

Com-

parator,

Slope

Selector,

Trigger

TD

and

Driver,

and

Main

Trigger

Generator

circuits.Fig.3-3

shows

a

detailed

block

diagramofthe

Main

Trigger

Generator

circuit

and

the

sche-

matic

is

shown

on

diagram 2

at

the

rearofthe

manual

.

3-

5

Circuit

Description-71353N

R2

LEVEL

(Main)

Main Trigger Signal

I I

1

S2

SLOPE

(Main)

Holdoff Pulse

Slope

Selector

and

Level

Comparator

Q402

and

0404

are

connectedasa

differential

com-

parator.The

reference

voltage

for

the

comparator

is

selected

by

the

settingofLEVEL

controlR2.

The

Main

Trig

Level

Center

adjustment,

R410,

sets

the

levelatthe

base of

0404sothe

sweepistriggeredatthe0volt

point

of

the incoming

trigger

signal

when

the

LEVEL

controlisset

to

the

centerofthe

positiveornegative

slope

region

.

The

LEVEL

control

varies

the

voltage

on

the

base of

Q404

to

select

the

point

on

the

trigger

signal at

which

triggering

occurs

.

0408

and

R408

establish

the

emitter current

for

Q402

and

Q404

.

Priortothe

arrivalofa

trigger

signal,

with

the

LEVEL

control

settothe

centerofthe

positive

or negative

slope,

Q402

and

Q404

are

passing

equal

currents

.

Assume

that

a

positive-going

signalisappliedtothe

MAIN

TRIG

IN

connector

and

that

the

LEVEL/SLOPE

controlisset

to centeronthe

positive

slope.The

signal at

the

MAIN

TRIG

IN connectorisinverted

by the Main

Trig-

ger

Preamp,

appearingatthe

baseofQ402asa

negative

going

signal.This causesadecreaseincurrent

through

Q402,

and

becauseofthe

common

emitter

source

(Q408

and R408),

the

current

through

Q404

increases.The

de-

creased

collector

currentofQ402

biases

Q418ina

reverse

direction,

while

Q416

becomes

more

forward

biased

due

to

the

increased

current

through

Q404

.

With

SLOPE

switchS2in

the+position,

the cathode

of

CR424isgrounded,

forward

biasing

CR424,

which

reverse

biases

CR423

.Atthe

same

time,

the

baseof0428isat

3-

6

Fig.3-3.Main

Trigger

Generator

detailed

block

diagram

.

ground and

Q428isoff.This

causes

CR421tobe

reverse

biased

and

CR422isforward

biased

through

Q416.An

in-

creased

currentisappliedtothe

TriggerTDand

Driver

circuit

through

Q416

and

0422

(see Fig.3-4)

.

When

the

SLOPE

switchissettothe-position,

Q428

and

CR421

are

forward

biased

and

CR422isreverse

biased

.

CR424isreverse

biased

and

CR423isforward

biased so

that

current

flows

through

Q418

and

CR423tothe

Trigger

TD

and

Driver

circuit

.

TriggerTDand

Driver

The

Trigger

TD

stage

shapes

the

outputofthe

com-

parator

to

provideatrigger

pulse

withafast

leading

edge

.

Tunnel diode

CR430isquiescently

biased

so that

it is

in

its

low-voltage

state.Increased

trigger

current

from

Q416

and

CR422or0418

and

CR423

through

R432,

L432

and

CR430

causes

CR430toswitchtothe

high-voltage

state

.

The

resulting

fast-rise

positive

stepiscoupled

through

emitter-follower

Q434toC451

and

C461inthe

Main

Trig-

ger

Generator

stage

.

Main

Trigger

Generator

The

Main

Trigger

Generator

includes

Q454,

Q466,

CR470

and

CR475.The

functionofthis

stageisto

supply

a

fast-rise

trigger

signal to

the Main

Sweep

Start Multi.For

normal

triggering,

this signalisdeveloped

after

receiptofa

fast-rise

transition

from

the

TriggerTDand

Driver

stage,

except

during

holdoff

.

O

Level

Slope

Trigger

Main

Compar-

Selector

To

and

Trigger

ator

Driver

Generato

Triggered

Q402,

Q416,

Q466,

Sweep

Enable

0404, Q418,

CR430,

CR470

Q408 0428

Q434

0454,

CR475

+5

V

+15

V

1

L__________

+5V

i

LEVEL/SLOPE

- -

+15

V

+5

V

n

v

I

VWCT1

W

Fig

.

3-4

.

Trigger current

path

for

positive

slope

triggering

.

Z

Circuit

Description-71353N

For

the

following

description

of operation,

assume

that

the

MODE

switchissettoNORM

and

that

a

trigger

signal

is

appliedtothe

MAIN

TRIG

IN

connector

.

CR470

and

CR475

are

bothintheir

high

state-,

until

the

holdoff

signal

switches

themtothe

low

state

.

The

holdoff

signal

from

pin17of

U720isa

positive

pulse

which

for-

ward

biases

both

0454

and

Q466

(see

the

Holdoff

Circuit

discussion

under

Main

Sweep

Generator

in this

section)

.

When

these

transistors

are

forward

biased,

they

divert

cur-

rent

from

CR470

and

CR475

which

causes the tunnel

diodes

to

switchtothe

low

state

.

The

after

holdoff appearsasa

positive

tran-

sition

at

C451

and

C461.The

positive

transition,

coupled

through

R461

and

R462,

causes

CR470

to

switchtoits

high

state.This higher

level,

through

R472,

brings

CR475

up

to near

its

switching

current.The

positive

transition

is

also

coupled through

C451

and

R451,

and

after3.5

nano-

seconds

of delay,

through

R474toCR475.The

short

delay

assures

that

CR470

has

had

timetoswitchtoits

high

state,

arming

CR475

before

arrivalofthe

switching

signal

at

CR475.This

prevents

extraneous

noise

from

prematurely

activating

CR475.CR475

then

switches to

its

high

state

.

The

fast-rise

positive

trigger

from

CR475iscoupledtothe

Main

Sweep

Start

Multi,

Q722/Q726

.

MAIN

SWEEP

GENERATOR

The

Main

Sweep

Generator

circuit

producesasawtooth

voltage

which

is

amplifiedbythe

Horizontal

Amplifier

circuittoprovide

horizontal

sweep

deflection

on

the

CRT

of

the

indicator

oscilloscope.This

output

signalisgenerated

on

command

(trigger

pulse)

from

the Main

Trigger

Gener-

ator

.

The

Main

Sweep

Generator

also

producesaMain

Sweep

Gate

pulse

coincident

with

the

time

that

the

Main

Sweep

runs.The

Main

Gate

pulseisprocessedbythe

Sweep

Gate

Out

circuit

and the

indicator oscilloscope

for

CRT

unblanking

and

Auxiliary

Gate

output.In

addition,

the

Main

Sweep

Generator

produces

several

control

signals

for

other

circuits

within

the

instrument

.

Fig.3-5

showsade-

tailed

block

diagram

of

the

Main

Sweep

Generator

and

the

schematic

is

shownondiagram 3atthe

rear

of

the

manual

.

The

MAIN

TRIGGERING

MODE

switch allows

three

modes

of

operation.When

the

NORM

button

is

pressed,

a

sweepisproduced

only

when

a

trigger

pulseisreceived

from

the

Main

Trigger

Generator

circuit.When

the

AUTO

buttonispressed,

a

sweepisproducedasin

NORM

except

thatafree-running

traceisdisplayed

whenatrigger

pulse

is

not

present

.

SINGLE

SWEEP

MODE

operationisalso

sim-

ilartoNORM

operation

except

that

the

sweepisnot

re-

current.The

RESET

button

must

be

pressedtoview

another

trace

.

The

following

circuit

descriptionisgiven

with

the

MAIN

TRIGGERING

MODE

switch

pressed

to

3-

8

NORM.Differenceinoperation

for

the

other

two

modes

is

discussed

later

.

Main

Sweep

Start

Comparator

Q722, Q726,

and

Q728

comprise

the

Main

Sweep

Start

comparator.In

the

absenceofa

trigger,

Q722

is

off

and

Q726isheld

on

by

the

high

level

from

3ofU720.The

collector

of

Q726islow

and

this

lowiscoupled

through

emitter

follower

Q728

to

pin1of

U750,

thus

preventing

a

sweep.When

the

Main

Trigger

Generator

supplies

a

trigger,

the

positive

transitioniscoupled

to

the

base of

Q722.The

base

of

Q722

rises

above

the

level at

the

baseofQ726

and

the

current

through

common

emitter

resistor

R724

is

di-

verted

from

Q726

to

Q722.The

collectorofQ726

rises

and

the

positive

step

is

coupled

through

emitter-follower

Q728

.

The

positive

step

appears

across

divider

R731/R732

causing

pin1of

U750togo

positive,

thus

starting

the

sweep

.

Sawtooth

Generator

The

lower

half

of

the

U750

diagram

symbol

constitutes

a

Miller

Integrator.When

pin1is

positive,alinear

sawtooth

(positive-going)

is

generated

and

appears

at

pin8.

The

timing

components,

Rt and Ct

connected

to pins8and

9,

determine

the

rate

of

changeofthe

sawtooth

waveform

.

Q774

prevents

high-speed

error

currents

from

being

coupled

into

U750

by

wayofC754

and

pin9.

Sweep

Stop

Comparator

The

Sweep

Stop

Comparator

consists

of

Q794

and

Q796.In

the

absenceofa sawtooth

signalatpin8of

U750,

Q796

is

conducting

and

Q794

is

held

offbythe

positive

level

setatits

basebyR795,

the

Main

Sweep

Length

adjust-

ment.When

the

sawtooth

voltageatpin8of

U750

raises

the

base of

Q796

higher

than

the

base of

Q794,

Q796

turns

off

and

Q794

turnson.

The

collector

of

Q794

rises

and

the

positive stepiscoupled

through

emitter

follower

Q792

to

pin16of

U720

and

sweep

holdoff

begins

.

The

positive

step

at

pin16will

also

be seenatpin

17

of

U720,

and

conse-

quentlyatthe

bases

of

Q454

and

Q466

(Main

Sweep

Generator

Circuit).These

transistors

are

forward

biased,

which

diverts

the

current

from

CR470

and

CR475

and

causes

the tunnel

diodestoswitchtotheir

low

state.As

a

result,

Q722

turns

off

and

Q726

turnson.

The

collector

of

Q726

drops

and

the

negative

stepiscoupled

through

emitter

follower

Q728,

thus

ending

the

sweep

.

Holdoff

Circuit

The

Holdoff

Circuit

consists

of pins8,10,

16,

and

17 of

U720

plusRandCtime

constants

selectedbythe

TIME/

DIV

switch

.

The

holdoff

prevents

re-triggering

the

sweep

generator

until

after

the

sweep

timing

capacitor(s)

has

dis-

charged

and

sweep

circuits

are

again

ready

to generate

a

sweep

.

O

MODE

DISPLAY

MODEI

Fig

.

3-

5

.

Main

Sweep

Generator

detailed

block

diagram

.

M

TIME/

DIV

To

Composite

Sweep

Out

and

Mixed

Sweep

Comparator

Holdoff

to

Dly'd

Sweep

Trigger

Generator

Holdoff

to

Main

Trigger

Generator

Circuit

Description-71353N

At

the

endofthe

sawtooth

waveform,apositive step

is

coupledtopin

16 of

U720,

by

way

of

the

Sweep

Stop

Comparatoraspreviously

described.The

positive

pulse

seen

at

16 of

U720iscoupled

internally

through

U720

to

17

and

in

turntoQ454

and

Q466inthe

Main

Trigger

Generator.Q454

and

Q466

are

turned

on,

thus

robbing

the

current

from

CR470

and

CR475,

switching

themtothe

low

state.This

prevents

the Main

Sweep

Start Multi

from

gener-

atingasweep

.

Afteratime

determined

by the

timing

components

at

pin8,internal

circuitry

within

U720

switches

17

to

its

low

state,

ending the

holdoff

gate.The

Main

Trigger

Gener-

atorisreleasedtogenerateatrigger

signal

.

A

negative

gate

coincident

with

the

positive

holdoff

gate,

appears

at

10ofU720.This

negative

gateisin-

vertedbyQ748

and

coupledtothe

Delayed

Sweep

Gener-

ator

for

composite

holdoff

functions

.

Trig'd

Lamp

Driver

When

the

main

sweep

gateishigh

and

the

sweep

is

running,

the

TRIG'D

lampison.At

all

other times

the

lampisoff

.

Delay

Pickoff

The

upper

halfofthe

diagram

symbol

for

U750

includes

the

Delay

Pickoff

circuitry.Inside

U750,

the

main

sweep

sawtooth

signalisappliedtoone

sideofa comparator

circuit

.

6isconnectedtothe

other

sideofthe

com-

parator

.

The

setting

of

the

DELAY

TIME

MULTIPLIER

control,

R19,

determines

the

pointonthe

main

sweep

saw-

toothatwhich

the

comparator

switches

.

When

the

comparator

switches

(delay

pickoff

occurs),

a

positive

gate

appearsatpin4of

U750.This

gate

terminates

at

the endofthe

main

sweep

sawtooth

.

The

positive-going

gateatpin4of

U750

is

coupled

through

emitter-follower

Q762

to

the

Delayed

Trigger

Generator

.

Auto

Triggering

Mode

Operationofthe

Main

Sweep

Generator

circuitinthe

AUTO

positionofthe

MAIN

TRIGGERING

MODE

switch

is

the

sameasfor

NORM

position

just

described

when

a

trigger

pulseisapplied.However,

whenatrigger

pulse

is

not

present,afree-running

reference

traceisproducedinthe

AUTO

position.This

occursasfollows

:

The

Auto

Triggering

circuit

consistsofpinsI,3, 6,

and

19ofU720

.

When

the

AUTO

buttonofthe

MAIN

TRIG-

3-

1

0

GERING

MODE

switchispressed,alowatpin19of

U720

enables

the

Auto

Circuit.Whenarepetitive trigger

signal

above

30

Hz,

andofadequate

amplitudeisappliedtothe

Main

Sweep

Start

Comparator

and

pin1of

U720,

the

in-

ternal

Auto

Multiatpin6of

U720

charges

towards

five

volts

through

C786

and

R786,

butisdischargedbyeach

incoming

trigger

pulse

.

In

the

absenceofa

trigger

pulse,

C786

charges

towards

+5

V,

switching pin6to

its

high

state

and

pin3to

its

low

state.Q726

turns

off,

its

collector

rises

andahigh

is

coupled through

emitter

follower

Q728topin1of

U750,

causing

the

sweeptorun

.

Single

Sweep

Operation

Operationofthe Main

Sweep

Generatorinthe

SINGLE

SWEEP

position of

the

MAIN

TRIGGERING

MODE

switch

is

similartooperationinthe

NORM

positionaspreviously

described.However,

after

one

sweep

has

run,

all

other

sweeps

are

inhibited

until

the

RESET

buttonispressed.A

READY

lamp

is

providedtoindicate

when

the

sweep

is

readytoacceptatrigger

.

The

Single

Sweep

circuit

consists

of pins

11, 12, 14, 15,

and

17ofU720.For

SINGLE

SWEEP

operation,

the +5

volt

supplyisappliedtopin12of

U720.The

holdoff

pulse

at

pin17of

U720

goes

positive,

preventing

generationofa

sweep.When

the

RESET

buttonispressed,

pin15is

mo-

mentarily

held to

ground,

17

goes

lowtoallow

the

Main

Trigger

Generatortoacceptatrigger.The

holdoff

line

(pin

17

of

U720)

stays

low

untilasweep

has been

com-

pleted.At

this

time,

the

holdoff

pulse

rises at

pin17and

staysinthe

holdoff

state

until

the

RESET

button

is

pressed

.

0744

actsasa

switch for the

READY

lamp.When

the

holdoff

gateatpin17is

high,

preventing

the

sweep

gener-

ator

from

acceptingatrigger,

11ishigh

and

Q744

and

the

READY

lamp

are

off.When

the

RESET

button

is

pressed,

the

holdoff

gateatpin17goes

low

and

allows the

Main

Sweep

Generatortoacceptatrigger.Pin11rises

and

turnson0744, which

provides

the

current

to

turnonthe

READY

lamp

.

Sweep

Lockout

Q714,

Q716

and

pins3,16,

and18comprise

the

Sweep

Lockout

circuit.The

Sweep

Lockout

circuitisfunctional

when

the

7B53NisinstalledintheBHorizontal

compart-

ment

of an

indicator oscilloscope

which

accommodates

two

horizontal

plug-in

units,

anditis

desiredtooperateinthe

Alternate

Horizontal

Mode,orto

operate

the

71353N

as

a

delayed

sweep

unit.Lockoutisappliedtothe

7B53N

during the

time

that

the

sweep

from

the

associated

time

base

is

displayed

.

The

indicator

oscilloscope

controls

initiation

of

a

sweep

by

supplying

current

to

the

base of

Q714

when

lockout

is

required.This

current

causesapositive step

at

pin18of

U720.Pin3of

U720

steps

positive

and

Q726

turnson.

The

collector

of

Q726

falls

and

the

lowiscoupled

through

emitter

follower

Q728

to

1ofU750,

thus

preventing

the

sweep.If

lockout

is

initiated

while

the

sweep

is

running,

the

leading

edge

of

the

lockout

pulseisdifferentiated

through

C719

and

D719,

and

appearsasa

high

at

pin16of

U720

.

This

starts

the

holdoff

cycle.(The

holdoff

cycleisas

described

previously)

.

Delayed

Mode

Control

When

the

7B53N

is

installedintheBHorizontal

com-

partment

of an

indicator

oscilloscope

with

two

horizontal

compartments,

the

Delayed

Mode

Control

determines

whether

the

7B53N

operatesasan

independent timebase

or

as

a

delayed

sweep

unitinthe

triggerable

after

delay

time

mode.When

approximately+3to4.5

voltsispresent

at

interface

connector B1

(and

therefore

pin13of

U720),

the

Auto

Circuit

(previously

described)isdisabled.A

sweep

can

be

enabled

only

by a

trigger

pulsetothe

Sweep

Start

Comparator.During

delay

time determined

by

the

settings

of

the

delaying

sweep

unit,

sweep

lockout

(previously

de-

scribed)

inhibits

the

sweep

.

After delay

time,

the

7B53N

J18

DLY'D

TRIG

IN

OR D

LY'D GATE OUT

+5

V

(Dly'd)

T

I l

Ext

Int

SOURCE

S18

i

10

Int

I I

I

l

Delayed

Gate

from Delayed

Sweep

Start

Control

Inter

Trigger

Signal

from Vertical Unit

Dly'd External

Trigger

Preamp 0508,

0512,

0516

S10B



(MAINSw1



S15

IME/DIV

I

DLY'D

TRIGGER

I

MODE

(AMPL)

I

RUNS

AFTER)

Fig.3.6.

Delayed

Trigger

Preamp

detailed

block

diagram

.

Circuit

Description-712153N

can

be

triggered.An

approximate

zero

volt

level at

13

of

U720

enables

the

Auto

Circuit,

causing

the

7B53N

to

operateasan

independenttime

base

.

DELAYED

TRIGGER

PREAMP

The

delayed

Trigger

Preampisvery

similar

to

the

Main

Trigger

Preamp

previously

described

.

Therefore,

only

those

portions

that

are

different

will

be

describedindetail.This

circuitry

selects

trigger

source

and

coupling

for the

signal

driving

the

Delayed

Trigger

Generator.Fig.3-6

shows

a

detailed

block

diagram

of

the

Delayed

Trigger

Preamp

circuit

and

the

schematic

of

this

circuitisshown

on

diagram4at

the

rear of

the

manual

.

Dly'd

Trigger

Source

Switching

U530

initiates

the

Delayed

Trigger

Mode.When

the

DISPLAY

MODE

switchisset

to

INTEN,

DLY'D

SWP,

or

MIXED

position

and

the Delayed

Triggering

LEVEL

controlisin

the

OUT-DLY'D

SWP

TRIGGERABLE

position,

a low

level

is

coupled through

08

to

pin6of

U530,

which

allows

U530toacceptatrigger

.Ahighatpin

6

(DISPLAY

MODE

switch

settoMAIN

SWP,

TIME/DIV

S12

DISPLAY

MOD

Trigger

Inhibit

08

S17

COUPLING

(Dly'd)

Dly'd

Trigger

Coupling

0562

~

J

To

Delayed Trigger Slope

Selector and

Level

Comparator

F

3-11

Circuit

Description-71353N

OR

DL'Y

TIME

switch

set

to

AMPL,

or

the

Delayed

Triggering

LEVEL

controlatthe

IN-RUNS

AFTER

DL'Y

TIME

position)

causes

U530torefuse

a

trigger

.

U530

also

performs

the

functionofselecting

either

the

Dly'd

Internal

Trig

Amp

or the

Dly'd

External

Trig

Amp

as

the

sourceoftrigger

.

When

pin4of

U530ispositive,

pins

7

and10are

activated

andanexternal

trigger

must

be applied

to the

DLY'D

TRIG

IN

connector.When

pin4is

low

(near

ground),

pins2and

15

are

active

and

an

internal

trigger

sourceisselected

.

Dly'd

External

Trig

Amp

Q508,

Q512

and

Q516

comprise

the

Dly'd

External

Trig

Amp.This

circuitisidenticaltothe

Main

External

Trigger

Preamp.The

amplifier

providesacurrent

gain

and

is

terminated

by

R519

at

10 of

U530

.

Balanced-to-Single-Ended

Converter

This

circuit

includes

Q552,

Q554

and

Q558.Except

for

minor

differences

in

component

values,

the

circuitry

is

identical

with

the

Balanced-to-Single-Ended

Converter

in

the

Main

Trigger

Preamp.The

output

signal

at the emitter

of

Q558

is

inverted

from

the

signal at

the

DLY'D

TRIG

IN

connector

.

R15

LEVEL

(Dly'd)

Trigger

Signal

Dly'd

Level

Comparator

Q602,0604

Dly'd

Slope

Selector

0616,

0618

0828

SLOPE

(Dly'd

)

Delay

Gate

from

Delay

Pickoff

Dly'd

Swp

Holdoff

Dly'd

Trigger

Generator

Q654, Q666,

Q862,

CR670

CR675

DELAYED

TRIGGER

GENERATOR

To

Dly'd

Sweep

-~

Holdoff

Dly'd

Sweep

Enable

3-12

Dly'd

Trigger

Coupling

Fig.3-7.Delayed

Trigger

Generator

detailed

block

diagram,

When

COUPLING

switch

S17

is

settoDC,

0562

is

forward

biased

by wayofR56

and

R561

.

The

trigger

signal

is

direct

coupled

between

the

emitter

of

Q558

and

the

base

of

Q602

(Slope

Selector

and

Level

Comparator)

.

If

the

COUPLING

switchissettoAC,

Q562isreverse

biased

and

the

trigger

signaliscoupled

through

C562

.

DELAYED

TRIGGER

GENERATOR

The

Delayed

Trigger

Generator

circuitry

is

essentially

the

same

as

the

Main

Trigger

Generator,

except

thereisno

provision

for

automatic

mode

of

triggering

.

Therefore,

only

the

circuits

that

are

different

willbedescribed

in

detail.For

a

detailed

description of

the

rest

of

the

circuitry,

refer

to

the

Main

Trigger

Generator

.

Fig.3-7

showsadetailed

block

diagram

of

the

Delayed

Trigger

Generator,

and

the

schematicisshown

on

diagram5at

the

rear

of the

manual

.

Slope

Selector

and

Level

Comparator

This

circuit

consistsofQ602, Q604,

Q616,

Q618

and

Q628

.

Operation

is

identical

to

the

Slope

Selector

and

Level

Comparator

on

the

Main

Trigger

Generator

diagram

.

O

When

the

input

signal

at

the

base of

Q602

passes

through

the

level

set

at

the

base of

Q604,

an

increaseincurrent

occursatthe

output

.

Trigger

TD

The

Trigger

TD

is

CR630.The

increased

current

caused

by

applying

a

trigger

signaltothe

Slope

Selector

and

Level

Comparator

circuitiscoupled

through

R632

and

CR630,

switching

CR630toits

high

state

.

Delayed

Trigger

Generator

The

Delayed

Trigger

Generator

circuit

includes

Q654,

Q666, Q862,

CR670

and

CR675.Operationofthe tunnel

diodes,

CR670

and

CR675,

is

identicaltooperationofthe

TD'sinthe

Main

Trigger

Generator

.

If

the

DLY'D

LEVEL

controlispushed

to

the

IN-RUNS

AFTER

DL'Y

TIME

position,

S15

isinthe

"open"

position

and

current

through

R871,

CR655,

and

R674

to

the

Sweep

StartTD(CR675)

biases

CR675

just

below

the

switching

level.When

the Delay Gate

is

generated

(at

the

Trigger

Pickoff),

the

positive stepatthe

junction

of

CR866

and

CR869

forward

biases

Q862.This

increases

current

through the

Sweep

Start

TD,

causingitto

switch

to

the

high

state.This

occurs

immediately

upon

arrival

of

the

Delay

Gate,

without

need

foradelayed

trigger

input

.

When

the

DLY'D

LEVEL

controlisin

the "out"

position

(DLY'D

SWP

TRIGGERABLE),

S15

is

closed,

forward

biasing

CR71.Q954

becomes

forward

biased

and

Q862isreverse

biased.The

static

current

through

CR675

is

at

a low

level.Q862

becomes

forward

biased

upon

arrival of

the

Delay

Gate

signal at

its

emitter

(via

CR866).The

resulting

current

biases

the

Sweep

StartTDjust

below

the

switching

level.A

trigger

signal

from

the

Trigger

TD

(CR630)

then

causes

the

Sweep

StartTDto

switch to

the

high

state

.

The

Dly'd

Swp

Holdoff coupledtothe

basesofQ654

and

Q666

prevents

the

Sweep

Start

TD

from

switching

until

after

the

main

sweep

has

occurred

.

DELAYED

SWEEP

GENERATOR

The

Delayed

Sweep

Generator

produces

a

sawtooth

voltage

which

is

amplified

by

the

Horizontal

Amplifier

circuitstoprovide

a

delayed

sweep

CRT

display.The

sawtooth

output

voltageisgeneratedoncommand

of

the

Delayed

Trigger

Generator.The

Delayed

Sweep

Generator

also

producesaDelayed

Sweep

Gate

pulse,

coincident

with

the

time

that

the

Delayed

Sweep

Generator

runs,

to

be

processed

by

the

Sweep

Gate

Out

circuit

and

the

indicator

oscilloscope

for

CRT

unblanking.Fig

.

3-8

showsadetailed

Dly'd

Swp

Start

Multi

Dly'd

Swp

Start

Control

Mixed

Swp

Comparator

Circuit

Description-71353N

block diagramofthe

Delayed

Sweep

Generator and

the

schematicisshown

on

diagram6at

the

rearofthe

manual

.

Q882

and

Q886

comprise

the

Dly'd

Swp

Start

Multi

.

This

circuitisconnectedasa

bistable

multivibrator,

with

Q886

normally conducting

and

Q882

off

.

When

the

Sweep

StartTDswitches

to

its

high

state,

the

positive

step

appearsatthe

base

of

Q882.This

causes the

multitoflip,soQ882ison and

Q886

off.The

collector

of

Q886

goes

positive.The

Sweep

Start

TDisheldinits

high

state

for

the

durationofthe

Delay

Gate

.Atthe

endofthe

Delay

Gate,

the

Dly'd

Sweep

Start

Multi

reverts

to

its

original

state

with

Q882

off

and

Q886on.

The

Dly'd

Swp

Start

Control

circuit

includes

Q902,

0904

and

Q906.This

circuit

couples

a

positive gatetopin

1ofU930

(Miller

Integrator)tocontrol

the

period

during

whichasawtooth

is

generated

.

In

all

Positions

of

the

DISPLAY

MODE

switch

except

MIXED,

0902

and

Q904

are

inactive

due

to

reverse bias

current

via

CR901,

S12

and

the+5volt

supply

.

When

the

collectorofQ886

(Dly'd

Swp

Start

Multi)

goes

positive,

Q906

couples

the

positive gate

to

pin1of

U930,

initiating

the

generationofa

delayed

sawtooth.At

the

endofthe

Delay

Gate,

the

collectorofQ886

drops.This ends

the

positive

gate to

pin1of

U930,

terminating

the

delayed

sawtooth

.

When

the

DISPLAY

MODE

switchissettoMIXED,

the

anode

circuitofCR901

is

open

.

The

gate

from

the

Main

Swp

Start

Multi

is

negative-goingatthe

baseofQ904.The

resulting

current

from

-Q904 forward

biases

Q906,

and

a

positive gateiscoupledtopin1of

U930

.

Q888, Q892,

Q896

and

Q898

comprise

the

Mixed

Swp

Comparator

circuit

.

This

circuit

determines

whether

U930

is

runningatthe

main

sweepordelayed

sweep

rate

.

With

the

DISPLAY

MODE

switch

settoMIXED,

Q892

is

forward

biased.The

main

sweep

sawtooth

at

the

emitter

(and

thus,

the

collector)ofQ892isa

positive-going

ramp

.

This

causesaramp

of

increasing

current

through

0896

.

During

the

time

thataDelay Gate

is

not

being

generated,

Q882

(Dly'd

Swp

Start

Multi)isbiased

off

and

Q888ison

.

In this

condition,

U930, Q888,

Q896

and

Q898

form

a

operational

amplifier.The

negative-going

ramp

at

the

collectorofQ896

becomesapositive-going

rampatpin

8

of

U930,

runningatthe

main

sweep

rate

.

3-13

i

Mainframe

Mode

-L

A76

Info

Mainframe

Mode

B7

,

Information

From

Main

Swp

Start

Comparator

Main

Sweep

Sawtooth

S12

DISPLAY

MODE

MIXED

TIME/DIV

S10B

DLY'D

Aux

Z

Axis

Control

Q984,Q988

Dly'd

Sweep

I

Start

Control

+5

V

Q902,

Q906

0904

10

I

Mixed

Sweep

Comparator

Q888,

Q892

Q896,

Q898

DISPLAY

MODE

Aux

Z

",

Axis

Out

Q992

Dly'd

Swp

Stop

P/O

U930

Main

Swp

Gate

Main

Sweep

Holdoff

Dly'd

Sweep

Lockout

Multi

Q942,

Q944

Dly'd

Sweep

Holdoff

0954

Holdoff

to

Delayed

--I

"

Trigger

Generator

S12

DISPLAY

MODE

A3

B3

Fig

.

3-

8

.

Delayed

Sweep

Generator

detailed

block

diagram

.

S10B

c

TIME/DIV

-1

-

DISPLAY

MODE

v

(DLY'D)

Composite

Sweep

Gate

~'

Composite

S

weep

Gate

Out

Al

Out

Q922,

0924,

0928

V

Aux

Z-Axis

Out

A17

W

Ci1

Z

LEVEL

S15

Dly'd

Trig

T

In

-15

V

-0

410

When

the

Delay

Gate

is

generated,

the

Delayed

Trigger

Generator

forward

biases

Q882.The

collector

current

through

R888

reverse

biases

Q888,

opening

the

operational

amplifier

loop.U930isreleased

to

runatthe

delayed

sweep

rate.Therefore,

the

sawtooth

at pin8of

U930

will

first

run

at

the

main

sweep

rate

and

then

change

to

the

delayed

sweep

rate

when

the

Delay

Gate

is

generated

.

Dly'd

Swp

Stop

Circuit

The

upper

half

of

the

diagram

symbol

for

U930

constitutes

the Dly'd

Swp

Stop

Circuit.The

setting

of

the

Dly'd

Sweep

Length

adjust

(R930)

determines

the

point

on

the

delayed

sawtooth

at

which

pin4of

U930

will

go

positive

.

Dly'd

Swp

Lockout

Multi

Q942

and

Q944

form

the

Dly'd

Swp

Lockout

Multi

.

This

circuit

serves

to

terminate

the

delayed

sweep

as

determined

by

the

setting

of the

Dly'd

Sweep

Length

adjust.When

4

of

U930

goes

positive,

Q942

becomes

forward

biased

.

The

negative-going

stepatthe

collectorofQ942

forward

biases

Q902

(Dly'd

Swp

Start

Control

circuit).Q904

and

Q906

become

reverse

biased,

dropping

the

levelatpin1of

U930

and

terminating

the

sweep

.

Dly'd

Swp

Holdoff

The

Dly'd

Swp

Holdoff

circuit

includes

Q954

.

The

holdoff

gateatconnectorGis

a

composite

of the

positive

gate

from

the

Dly'd

Swp

Lockout

Multi,

the

Main

Swp

Holdoff

Gate

via

R952;and,

when

the

DLY'D

LEVEL

controlissettoDLY'D

SWP

TRIGGERABLE,

the

positive

level

setby0954

.

With

the

DLY'D

LEVEL

control

set

to

DLY'D

SWP

TRIGGERABLE,

Q954

is

forward

biased

until

the

Delay

Gateisgenerated.This

pullsupthe

holdoff

linetoprevent

the

Sweep

Start

TD

from

switching to

its

high

state

with

a

trigger

signal

until after

the

Delay

Gateisgenerated

.

Composite

Swp

Out

Q962,

Q966

and

Q968

form

the

Composite

Swp

Out

circuit

.

When

the

DISPLAY

MODE

switch

is

settoMAIN

SWP

or

INTEN,

Q966isforward

biased,

coupling

the

main

sweep

sawtooth

to the

base of

0968.Q968

is

an

emitter-follower

stage

which

couples

the

signaltooutput

terminalsA3andB3.

If

DLY'D

SWP

or

MIXED

is

selectedbythe

DISPLAY

MODE

switch,

Q962

if

forward

biased

and

couples

the

delayed

sweep

or

mixed

sweep

sawtooth

to

the

base of

Q968

.

Composite

Swp

Gate

Out

Aux

Z

Axis

Control

AuxZAxis

Out

Circuit

Description-71353N

0966

and

Q968

or

Q962

and

Q968

(depending

on

DISPLAY

MODE

setting)

are

connected

as

an operational

amplifier,

providing a high

degree

of

gain

stability

.

The

Composite

Sweep

Gate

Out

circuit

includes

Q922,

Q924

and

Q928.The

output

at

the

collector

of

Q928

connects

to

interface

connector

pin Al

for useinthe

indicator

oscilloscope.In

the

AMPL

position

of the

TIME/DIV

OR

DL'Y

TIME

switch,

connector

A1isset

to

approximately

+4.3volts

(via

CR100)

to

unblank

the

CRT

.

Q928

serves

as

the

output

stage

.

With

the

DISPLAY

MODE

switch

settoeither

MAIN

SWP

or

INTEN,

Q922

couples

the

main

sweep

gate to

the base of

Q928

.

When

either

DLY'D

SWP

or

MIXED

is

selected,

Q924ison

.

The

gate

signalatthe

emitter of

Q906

(Dly'd

Swp

Start

Control)iscoupled

to the

baseofQ928

.

The

AuxZAxis

Control

circuit

includes

Q984

and

0988

.

This

circuit

uses the

indicator

oscilloscope

mode

and

switching

levels

to

determine

when

the

sweep

signal

from

the

7B53N

is

being

displayedonthe

CRT

.

Information

of

this

type

is

normally

used

only

when

operating

the

7B53N

in

a

four

plug-in

indicator

oscilloscope

.

Typical

levelstocause

the

Aux

Z

Axis

Control

to

intensify

the

CRT

are+5voltsatterminal

A16

and-0.6

volt

at terminal

B7.This

forward

biases

Q988,

resultingina

positive

levelatits

emitter

.

When

the

7B53N

is

used

in

a

three

plug-in

indicator

oscilloscope

and the

DISPLAY

MODE

is

set

to

INTEN,

0984

is

off

and

0988

is

forward

biased

.

Q992

is

the

Aux

Z-Axis

Out

stage

.

The

output

at

connector

DZ

is

connected

to pin

A17

on

the

interface

connector

and

then

to

the

Z-axis

circuit

in

the

indicator

oscilloscope

.Areductionincurrent

through

Q992

causes

the

CRT

trace

to brighten

.

For

this

description,

assume

that

the

7B53N

is

used

in a

three

plug-in

indicator

oscilloscope

.

As

described

under

AuxZAxis

Control,

when

INTEN

is

selected

by

the

DISPLAY

MODE

switch,

Q988

is

turned

on

.

The

positive

levelatthe

emitter of

Q988

reverse

biases

CR991,

which

reduces

conduction

of

Q992.The

positive

gate

appearingatthe

emitterof0906

(Dly'd

Swp

Start

3-1

5

Circuit

Description-7B53N

Control)

during the

delayed

sweep

further

reduces current

through

Q992,

causing

the

CRT

tracetointensify

beyond

the

normal

levelofunblanking

.

In

all

other

selections

of

the

DISPLAY

MODE

switch,

Q984isforward

biased

through

CR66.This

turns

off

Q988,

which

diverts

current

through

CR991.Q992

isinsaturation

and the

CRT

trace

brightnessisnow

setbythe

unblanking

signal

(Sweep

Gate)

.

HORIZONTAL PREAMP

The

Horizontal

Preamp

selects

the

sourceofthe

output

signal

(main

or

delayed sweep)

and

supplies

an

amplified

sawtooth

signaltothe

horizontal

circuits in

the

indicator

oscilloscope.In

addition,

this

circuit

contains

the

horizontal

magnifier

circuit

and

the

horizontal

positioning

network

.

Fig.3-9

showsadetailed

block diagram

of

the

Horizontal

Preamp

and

the

schematic

is

shown

on diagram

8atthe

rear of

the

manual

.

Ext

Horiz

Amp

The

Ext

Horiz

Amp

consistsofQ1004

and

Q1006

connectedasan

operational

amplifier.When

the

TIME/DIV

(DL'Y)

switch

is

in

any

setting

except

AMPL,

the

+5

volts

coupled through

CR

113,CR1016,

andR1016tothe

base

of

Q1006

holds

this

transistorinsaturation.Therefore,

any

incoming

external

horizontal

signalisby-passed

to

ground

(by

way

of

-15

volt

supply)

through

Q1006

and

U1020D

.

When

the

TIME/D

IV

(DL'Y)

switch

is

settoAMPL,

the

+5

voltsisremoved

from

the

base of

Q1006

allowing

Q1004

and

Q1006

to

function

as

an

operational

amplifier.The

output

signal,

inverted

from

the

inputatconnectorA,is

coupled through

R1007

.

Horiz

Display

Selector

Q1024

and

U1020A,

B,

C,D,andEcomprise

the

Horiz

Display

Selector

circuitry.Depending

upon

the

setting

of

the

DISPLAY

MODE

switchorthe

TIME/DIV

(DL'Y)

switch,

this

circuit

determines

which

signaliscoupled

to

the

Horiz

Out

Amp

.

When

the

TIME/DIV

(DL'Y)

switch

is

settoAMP,

U1020C

is

forward

biased

and

couples

the

signal

from

the

Ext

Horiz

Amp

to

the

Horiz

Out

Amp

.

Simultaneously,

+5

volts

is

disconnected

from

the

DISPLAY

MODE

switch,

assuring

thatnointernally

generated

sweep

signaliscoupled

through

at

this

time

.

In

all

other

positionsofthe

External Horizontal from Main

Trigger

Coupling

R8

POSITION

-15

V

DISPLAY

MODE

DS8

X10

MAG

X10

MAG

3-16

Fig.3-9.Horizontal

Preamp

detailed

block

diagram

.

TIME/DIV

(DL'Y)

switch,+5volts

is

connected

to

the

DISPLAY

MODE

switch

.

When

MAIN

SWPorINTEN

is

selectedbythe

DISPLAY

MODE

switch,

+5

voltsisapplied

to

the

anodeofCR

111

or

CR110

.

This forward

biases

U1020A,

which

couples

the

main

sweep

sawtooth

to

the

Horiz

Out

Amp

.

Q1024isalso

forward

biased so that

any

signal

developed

by

the

Delayed

Sweep

Generator

is

by-passedtoground

(via

the

-15

volt

supply)

.

Any

output

from

the

Ext Horiz

Ampiscoupled

to

ground

through

U1020D

.

If

the

DISPLAY

MODE

switch

is

settoDLY'D

SWP

or

MIXED,

+5

voltsisappliedtothe

anodeofCR108

or

CR107

.

This

forward

biases

U1020B,

which

couples

the

delayed

sweeporthe

mixed sweep

signaltothe

Horiz

Out

Amp.U1020E

is

also

forward

biased,

coupling

the

main

sweep

signal

to

ground

.

Position

Amp

The

POSITION

controlR8sets

the

bias

on

Q1014,

thus

setting

the

DC

current

coupledtothe

Horiz

Out

Amp

.

Horiz

Out

Amp

Circuit

Description-7853N

The

Horiz

Out

Amp

includes

Q1038,

Q1046,

and

U

1034A,

B, C,

andD.U1034B

andU1034C

are

connected

asanoperational

amplifer,

with

Rfbeing

R1052

andRi

the

Swp

Cal

adjust,

R60

.

U1034C

and

U1034D

formaparaphase

amplifier.This

stage

converts

the

single-ended

input

signaltoa

push-pull

output

signal

whichisnecessarytodrive

the

horizontal

output

stage

in

the

indicator oscilloscope

.

This

stage

also

provides

the

X10

magnification

and

Mag

Gain

adjustment.When

the

X10

MAG

switchisactivated,

R1045

and

R1055

are

connectedinparallel

with

R1046

and

R1056,

decreasing

the

emitter

degeneration

of

the

stage

.

This

increases

gain of

the

stage

10 times

.

The Mag

Gain

adjustisset

to

provideacalibrated

gain

when

magnified.A

contactofK1055

compretes

the

circuit

for

the

X10

MAG

indicator

lamp

when

the

X10

MAG

switch

is

activated

.

Q1038

and

U1034A

set

the operating

bias

for

the

output

Stage

.

Q1046

servesasa

constant-current

source for

U

1034C

andU1034D

.

NOTES

Tektronix 7B53N Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual