Feedback 550603 Manuel utilisateur

~

Sine-Square

,

Oscillator

550603

QUARE

OSCILLATOR

OUTPUT

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www.g0rsq.co.uk

Sine-Square

Oscillator

550603

Contents

Section

1

Description

Section

2 Operation

Section

3

Circuit

Description

Section

4 Maintenance

E

FEEDBACK

INSTRUMENTS

LIMITED

CROWBOROUGH

SUSSEX

ENGLAND

Telephone:

Crowborough

(08926)

3322

Cables: Feedback

Crowbr

Telex:

95255

Manual

603

EdC

0480

Printed

in

England

by

FI

Ltd,

Crowborough

I

Feedback

Instruments

Lld

Component replacement

Although

this

Feedback

manual

was

believed

to

be

correct

at

the

time

of

printing,

components

supplied

may

differ

slightly

from

those

described.

We

endeavour

continually

to

improve

our

equipment

by

incorporating

the

latest

developments

and

components,

even

up

to

the

time

of

despatch.

Whenever

possible

we

will

include

such

new

or

revised

information.

Whenever

possible,

replacement

components

should

be

similar

to

those

originally

supplied.

These

may

be

ordered

direct

from

Feedback

Instruments

Limited

or

its

agents

by

quoting

the

following

information;

1.

Equipment

type

2.

Equipment

serial

number

3.

Co'mponent

reference

4.

Component

value

Standard

components

can

often

be

replaced

by

alterna·

tives

available

locally.

COPYRIGHT

NOTICE

©

Feedback

Instruments

Limited.

All

rights

reserved.

No

part

of

this

publication

may

be

reproduced,

stored

in a

retrieval

system,

or

transmitted,

in

any

form

or

by

any

means,

electronic,

mechanical,

photocopying,

recording

or

otherwise,

without

the

prior

perm:ssion

of

Feedback

Instruments

Limited

2

The Health

and

Safety at Work Act

1974

We

are

required

under

the

Health

and

Safety

at

Work

Act

1974,

to

make

available

to

users

of

this

equipment

certain

information

regarding

its safe use.

The

equipment,

when

used

in

normal

or

prescribed

applications

withtn

the

parameters

set

for

its

mechanical

and

electrical

performance,

should

not

cause

any

danger

or

hazard

to

health

and

safety

if

normal

engineering

practices

are

observed

and

they

are

used

in

accordance

wi

th

the

ins

tructi

ons

suppl ied.

If, in

specific

cases,

circumstances

exist

in

which

a

potential

hazard

may

be

brought

about

by

careless

or

improper

use,

these

will be

pointed

out

and

the

necessary

precautions

emphasized.

While

we

attempt

to

give

the

fullest

possible

user

information

in

our

handbooks,

if

there

is

any

doubt

whatsoever

about

any

aspect

relating

to

the

proper

use

of

this

equipment

the

user

should

contact

the

Product

Safety

Officer

at

Feedback

Instruments

Limited,

Crowborough.

DESCRIPTION

1.1 Introduction

The

Feedback

SS0603

Sine-Square

Oscillator

is

based

on

a novel RC

oscillator

circuit

that

generates

sine waves.

A

block

diagram

of

the

main

features

of

the

circuit

is

shown

in fig

1.1.

The

fine

frequency

controlling

element

is

a

dual-gang

air-spaced

capacitor

effectively

giving

infinite

resolution,

and

the

ranges

are

selected

by

switching

the

requisite

resistors.

Sine-Square

Oscillator

SS0603

SECTION 1

A

thermistor

is

used

to

control

the

amplitude

of

oscillation.

A

current

input

Schmitt

trigger

is

used

to

produce

a

square

waveform

from

the

sine

wave

for

the

various

square-wave

output

options.

The

output

amplifier

provides

a

current

which

is

connected

to

the-slider

of

the

600-ohm

output

resistance,

thus

providing

an

output

from

a

true

GOO-ohm

output

impedance.

I

C

I R I

AI\.~I\./'-....a

output

•

...

voltage

lA

R Schmit t

current

600n

follower amplifier

trigger

S

chmitt

mode

sine/square

Fig

1.1

~

3

Feedback

Instruments

Ud

When

the

TTL

output

is

selected

the

output

1.2

Mechanical

current

is

shunted

by

a zen

er

diode

to

keep

the

output

The

550603

is

housed

in

an

ASS

plastic

case

made

in

voltage

and

output

impedance

at

values

suitable

for

two

halves

each

secured

by

two

screws

on

each

side.

TTL.

The

case

provides

the

main

structural

strength

of

the

A

separate

sinewave

'sync'

output

is

continuously

instrument.

Removal

of

the

case

gives access

to

all

available

for

oscilloscope

synchronisation

or

frequency

components.

Without

the

cover

the

SS0603

consists

of

monitoring

. a

horizontal

PWB

fixed

by

small

plastic

brackets

to

the

•

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FAEQUEN~

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Ill'

I

IIII

Fig 1.2

4

front

and rear panels.

This

provides a

structure

strong

enough

for

normal

handling

and maintenance.

The

low

power

dissipation

of

the

SS0603

obviates

the need

for

ventilation

holes. The

oscillator

tuning

capacitor

and associated resistors are

mounted

in a die-

cast metal screening

box

fixed

to

the

front

panel. This

provides

complete

electrostatic

screening and

protection

from

dust

for

the sensitive high-impedance

circuit.

All

controls

are situated on the

front

panel shown

in fig 1.2.

They

are:

Power Red push

button

power

switch

Separate red

power

indicator

Frequency

Rotary

range

switch

0..

r-.

Fine

frequency

control

(approx·

Q

imately

logarithmic

cal

ibrated

"

frequency

dial)

Waveform

Selection

Four

black push

buttons

Amplitude

Single

rotary

control

Output

terminals Main

output

from

pair

of

Red

and Black

4mm

socket

binding

posts

TTL

Output

Separate

4mm

socket

Sync

out

4mm

socket

Sine-Square Oscillator

SS0603

1.3 Specification

of

type

SS0603

The

SS0603

is

a general-purpose, solid state

'RC'

sine

oscillator

providing

sine wave

or

square wave

outputs.

Frequency

Range

10Hz

to

1MHz

in five switched ranges.

Resolution

-

infinite.

Range Overlap

25% at

top

of

each range and 10% at

bottom

of

each

range.

Scale

Accuracy

±5%

of

setting.

Typically

±2%

of

setting.

Frequency

Stability

Measured at 1

kHz

on 1

to

10kHz

range.

Drift

Typically

50ppm

per

10

minutes

measured

after

10

minutes

warm

up.

Supply

voltage change

Typically

0.003%

for

10% change

in

supply

voltage.

Main

Output

Waveforms

Sine, Square

or

Positive-only

Square wave selected

by

pushbuttons.

Output

Impedance

nominally

600

ohms.

5

Feedback

Instruments

L

td

Amplitude

Control

Single

continuous

control

nominally

0-15V

pk-

pk

at

1V

pk-pk

intervals.

Minimum

Usable

Output

Typically

200mV

pk-pk.

Amplitude

Stability

Typically

±1% over frequency range.

Offset

The

d.c

component

on the sine and square waveforms

is

separately set

by

internal adjustments and

is

normally

set

to

within

0.1V

of

zero. This d.c

component'

is

reduced

proportionally

to

the signal

output

by

the

output

control

(or

by

resistive loading).

Terminations

4mm

binding

posts (Hi-red and Lo-black) on J;';"

pitch

Purity

Sine

distortion

less

than

05%

at 1kHz.

Square wave rise and fall times -

less

than 100ns.

Auxiliary Outputs

TTL compatible square wave Available

only

when

appropriate

pushbutton

is

depressed.

Amplitude

+3.5

to

+4.5V

in the 'high' state and

o

to

·lV

in the

'Iow'

state.

Rise Time

Less

than 100ns.

6

Current sink capacity Eight standard

TT

L loads.

Termination

4mm

socket

Sync

Out

Continuously

available sine

waveform

Amplitude

2

to

6V

pk-pk

DC

component

Less

than

4V

d.c

Impedance 1k

r2

Termination

4mm

socket

Power requirements

Line

voltage

200!250V

or

1

00!125V

rms,

50

or

60Hz.

Consumption

5VA

Fuse

315mA

slow

blow

(20mm

x

5mm)

Littel

fuse

style

213

Seswick

TDC

123

Suss

GMA

Dimensions and Weight

Width

300mm

(1

2in)

Height

(with

feet)

115mm

(45in)

Depth

225mm

(gin)

Weight

2.1

kg

(4.63Ib)

OPERATION

2.1 I

nstallation

of

SS0603

The

oscillator

·is

packed

in inserts

of

expanded

poly-

styrene

to

prevent

damage

in

transit.

On

opening

the

end

of

the

corrugated

cardboard

container,

the

inserts

together

with

the

SS0603

should

be

smoothly

withdrawn

from

the

container.

Take

care

that

the

inserts

and

the

SS0603

are

held

together

during

this

time.

I

nspect

the

SS0603

and

if

any

damage

is

evident

immediately

notify

the

carrier.

2.2

Voltage

Selection

Ensure

that

the

instrument

is

set

to

the

appropriate

voltage

supply.

This

is

effected

either

by

inspecting

the

tag (if

fitted)

on

the

power

cable

or

by

checking

the

voltage

selection

switch

after

removing

the

top

cover

of

the

instrument.

Voltage

selection

is

accomplished

by

a slide

switch

on

the

printed

circuit

board;

it

has

positions

marked

'115'

and

'230'.

Set

the

switch

to

'115'

for

operation

from

100

to

125

volts

and

to

'230'

for

200

to

250

volts.

Wire

connections.

The

colour

code

of

the

power

supply

cable

is:

Brown

Live

Blue

Neutral

Green/Yellow

Ground

Sine-Square

Oscillator

SS0603

SECTION 2

The

ground

wire

is

connected

to

the

front

and

rear

panels

of

the

SS0603

and

to

the

common

terminal

on

the

front

panel.

2.3

Frequency

Selection

Any

value

of

frequency

in

the

range

10Hz

to

1MHz

may

by

obtained

by

use

of

the

range

switch

and

fine

frequency

control.

The

rotary

range

switch

provides

the

following

frequency

decades:

10Hz

to

100Hz

to

1.0kHz

to

10kHz

to

100kHz

to

1MHz

The

required

frequency

is

set

by

the

variable

control,

graduated

1

to

10

(0.9

to

13

with

overlap).

For

example,

to

set

3.6kHz

turn

the

range

switch

to

the

1.0kHz

to

1OkH z range

and

turn

the

variable

control

to

3.6.

2.4

Outputs

Selection

A

required

output

waveform

is

selected

by

pushing

one

of

the

four

output

selection

buttons

-

Sine,

Square,

positive

only

square

wave

or

TTL-compatible

square

wave.

Of

these

four

options,

only

the

TTL

output

is

available

from

a

separate

4mm

socket,

the

remainder

being

available

from

the

Main

Output.

7

Feedback

Instruments

Ltd

Main

Output

The

amplitude

of

the

output

waveform

is

set

by

the

output

control

knob

cal i

brated

from

0

to

15V

pk-pk

and

is

the

open-circuit

or

no-load

voltage.

The

output

impedance

is

600

ohms

and

any

loading

will

lower

the

output

voltage.

In

particular

if

loaded

with

600

ohms

the

terminal

voltage

will

be

half

that

indicated.

TTL

Output

This

output

is

available

from

a

separated

4mm

socket

when

the

appropriate

pushbutton

is

depressed.

The

separate

output

is

provided

as a

precaution

against

accidental

damage

that

might

ensue

should

an

overvoltage

be

applied

and

the

wrong

waveform

pushbutton

depressed.

The

output

ampl

itude

is

fixed

and

is

5-volt

TTL-compatible.

The

output

impedance

is

low

when

in

the

'0'

or

'1'

condition

and

is

high

during

transition.

SVnc

Output

This

extra

sinewave

is

continuously

available

and

is

Intended

for

such

functions

as

frequency

monitoring

and/or

oscilloscope

synchronisation.

In

the

latter

case

the

use

of

a

sinewave

allows

a

certain

amount

of

phase

adjustment

of

the

oscilloscope

display

by

adjustment

of

the

oscilloscope

trigger

level.

Phase relationships

The

sync

output

is

in

phase

with

the

main

sine wave

output

and

in

approximate

anti-phase

to

the

various

square

wave

outputs.

8

CIRCUIT DESCRIPTION

For

convenience

the

circuits

in

this

section

are

simplified

or

in

the

form

of

block

diagrams.

The

full

circuit

is

shown

in

fig

4.4.

3.1 RC Frequency Network

The

basic

oscillator

is

based

on

the

circuit

shown

in

fig

3.1.

V1

r;r

Fig

3.1

This

circuit

was

used

in

preference

to

other

RC

circuits

because

it

enables

the

frame

of

the

double-gang

variable

capacitor

C,

C'

to

be

grounded.

At

resonance

the

oscillatory

voltages

will be as in

the

phasor

diagram

fig

3.2.

The

amplifier

A

amplifies

VR'

by

X3,

to

provide

5ine-5Quare

Oscillator

550603

SECTION 3

the

voltage

V I

to

maintain

oscillation.

The

phase

and

gain

relationship

of

the

network

RCR'C'

is

very

similar

to

that

of

the

active

side

of

the

well-known

Wien Bridge.

1

The

resonant

frequency

is

f

'"

---

where

R

'"

R'

27TRC

and

C

'"

C'.

vc'~7

VR/

Fig

3.2

Phasor diagram

The

amplitude

of

oscillation

is

maintained

by

controlling

the

gain

of

the

oscillator

loop

by

means

of

a

thermistor.

3.2

RC

Oscillator Amplifier

Fig

3.3

shows

the

amplifier

used

to

maintain

oscillation

in

the

RC

network.

The

FET's

TR9a

and

TR9b

provide

suitable

high

impedance

inputs

for

connection

from

the

RC

network.

The

differential

input

stage

TR9-11

has

two

outputs.

One

output

is

used

for

feedback

to

the

RC

network

via

the

thermistor

and

the

emitter

follower

TR

14

while

the

other

output

goes

to

the

output'

circuit

which

includes

the

Schmitt

trigger.

The

gain

of

the

9

feedback 550603 Manuel utilisateur

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