IEC 30 Series - Output Limit Light (F32, F33, F34); Sweep Ramp Time (F34 Only); External Sync (F33, F34); Slew Rate Limitations (F32, F33, F34)

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2-2

SECTION 2

TRIG SYNC input

connector

(or

triggering

manually).

The

period

of

each

cycle

in

the

burst

is

controlled

by

the

main

generator

fre-

quency

controls,

and

the

duration

of

the

burst

is

controlled

by

the

SWEEP

TIME

controls.

Interesting

effects

such

as

discrete

fractions

of

a

cycle

may

be

created.

Swept

burst

may

also

be

created

by

adjusting

the

SWEEP LIMIT

control.

Actual

frequency

end

points

of

a

swept

burst

are

best

determined

by

careful

measure-

ment

of

the

FREQ

ANALOG

voltage.

g.

OUTPUT

LIMIT LIGHT (F32, F33, F34). -

Glows when any

combination

of

the

D-C

OFF-

SET

and

the

continuously

variable

OUTPUT

LEVEL

control

is

such

that

the

maximum

voltage

swing

of

the

output

amplifier

is

ap-

proached.

Adjusting

the

output AMPLITUDE

step

attenuator

will

not

affect

this

light

be-

cause

the

attenuator

will not

affect

this

light

because

the

attenuator

is

located

after

the

amplifier

final

stage.

This

is

a

"predictor"

circuit;

it

operates

independent

of

mode

or

waveform

selection.

h. SWEEP RAMP TIME (F34 only). -

The

SWEEP

TIME

controls

are

calibrated

in

ramp

up

time

(±5

percent)

and

this

does

not

include

the

retrace

(ramp

return

time)

of

about

10

percent.

Thus,

the

sweep

repetition

rate

is

not

a

simple

reciprocal

of

the

sweep

time.

i.

EXTERNAL SYNC

(F33,

F34). -

This

feature

(sometimes

called

"simple

sync")

per-

mits

the

function

generator

main

oscillator

to

be

"pUlled"

to

match

the

repetition

rate

of

an

external

periodic

signal.

This

pulling

action

is

limited

to about 1

percent

of

the

operating

frequency

and

tends

to

degrade

above 1 MHz.

The

sync

action

is

also

useful

in

generation

of

harmonic

and

subharmonic

relationships

to

the

external

signal.

NOTE

Be

certain

to

remove

the

external

signal

when not

using

it

because

it

will

introduce

phase

jitter

when

not

synchronized.

j. SLEW RATE LIMITATIONS (F32, F33,

F34). -

Either

the'

VCG input

or

the

internal

sweep

generator

may

be

adjusted

occasionally

to

create

voltage

slewing

rate

commands

in

excess

of

the

specified

(0.3v/

sec)

ability

ofthe

instrument

to

follow.

Problems

of

this

type

will

reflect

in

the

behavior

of

the

instrument

in

the

following

manner:

• OUtput

Frequency

-

The

change

in output

frequency

will

be

less

than

expected

for

a

slower

slew

rate.

•

Freq

Analog Output -

The

voltage

swing

will

be

less

than

expected

and

may

have

a

d-c

offset.

• CONT SWP Mode - In

this

mode

of

oper-

ation,

the

slew

limitation

may

be

encoun-

tered

in

the

sweep

ramp

retrace

period

because

it

slews

at

ten

times

the

rate

of

the

basic

ramp.

k.

CHART RECORDER DRIVE (F34 Only). -

A

constant-amplitude,

positive-going

sweep

voltage

is

supplied

at

the

rear

panel

for

driving

the

x-axis

of

scopes

and

chart

recorders

.

•

•

•

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