Gould J3B User manual

'

L.F.

SIGNAL

GENERATOR

J3B

Instruction

M a

nua

I

•}

GOULD

ADVANCE

Roebuck Road, Hainault,

Essex

..

Telephone: 01-500 1000

Telex: 263785

Telegrams: Altenuate Iiford.

FOR

SERVICE

MANUALS

CONTACT:

MAUR!TRON

TECHNICAL

SERVICEf

www

.mauritron.co.uk

TEl.

01844

·

351694

FAX: 0i

844

-

352554

Contents

SECTION

INTRODUCTION

SECTION 2

SPECIFICATION

3

SECTION 3

OPERATION

4

3.1

Switching On 4

3.2 Block Diagram 4

3.3 Selection

of

Frequency 5

3.4 Balanced

Output.

15-0-15v

rms

emf.

5

3.5

Low-Z

Output

3V

rms

emf.

Zo

""

10hm

6

3.6

Low Distortion Output 2.5V

rms

emf.

Zo~5K

Ohm

6

3.7 Square

Output

0

to

+SV Z

Zo<>1K!J

6

3.8

Output

Level

Meter

& Decibel

Scale

6

3.9 Relative Phase 6

SECTION 4

CIRCUIT

DESCRIPTION

7

4.1 Wien Bridge Oscillator 7

4.2

Power

Amplifier

7

4.3

Power Outputs 8

4.4

Square Wave

Output

8

4.5

Power

Supply 8

4.6

Meter

Circuit

9

4.7

Mains

Input

9

4.8

External D.C.

Supply

9

SECTION 5

MAINTENANCE

10

5.1 Removal

of

Covers 10

5.2 Removal

of

Oscillator Box

Cover 10

5.3 Removal

of

Printed Circuit

Board

Assemblies

10

5.4 Setting up

of

Wien Bridge FOR SERVICE MANUALS

Oscillator 10

5.5 Setting up

of

Power Supply

11

CONTACT:

5.6

Setting

up

the

Power

Amplifier

11

MAURITRON

TECHNICAL

SERVICES

5.7

Setting

up Squarer

11

5.8 Distortion 11·12

www

.mauritron.co.uk

TEL:

01844-351694

SECTION 6

COMPONENTS

LISTS

and FAX:

01844-352554

ILLUSTRATIONS

13·18

SECTION 7

GUARANTEE

AND

SERVICE

FACILITIES

22

ILLUSTRATIONS

Fig.1 Power

Supply

Tappings, links,

and Fuse ratings 4

Fig.2 Block Diagram 4

Fig.3

Graph

of

Distortion

and

Frequency

12

Fig.4

Component

Location Diagram 19

Fig.5

Circuit

Diagram

21

'

2

Introduction

The

Gould

Advance

J

38

Signal Generator

is

an

LF

instrument

mcorporating

a high

output

level

from

a balanced, floating

600

n

output.

The

main

output,

which

is

metered,

gives

15V

into

SOC

n

(30V

EMF).

The frequency range

of

10Hz

to 1OOkHz

is

provided

on

four

decade

ranges, and

the

6: 1

reduction

drive

with

capacitor

tuning

gives high resolution

of

frequency

with

minimum

bounce.

Three

additional

outputs

are available, a

lW

low impedance

output,

a

square

wave

output

and

a

low

distortion

output.

The

solid

state

circuitry

results in low

heat

dissipation,

giving a

high

order

of

frequency

stability

and

reliability.

Switched

step

attenuators

give 60dB

of

attenuation

and

the

variable level

control

can

be used

to

provide a

further

20dB

of

attenuation

with

negligible

hum

and

noise on

the

output.

'

Section1

FOR

SERVICE

MANUALS

CONTACT:

MAURITRON

TECHNICAL

SERVICEf

www

.mauritron.co.uk

TEL:

01844-

351694

FAX:

01844-

352554

f

r

I

!

-

f

~-

l

[

Components List and Illustrations

:::f

11)01

..

"''

~104

"

~,'

~ ~

'""

"

,.,.

''"'

~=

' --

I

U•PUT

I

Ron

--·-

I

lO•

...

:>-''~0~0~·-----

lOU

,...

.....

,

•oo

..

; •

''io'"'

~-

0

-~

\G

..

o

I{ICOMO

C>OJ

c

"'

"

Section

.,,.

••o•

~~~·

11101

11"0

IIIII

••u

••••

"'

••u

••·l

..

,

.

..

,

""

:11

coot C•o•

c•o•

co

11

"

Cl

CJ

C•

CH

Clo

TAIO)

roou

TRilJ

1',-,,o,~--~1.-oo-,---

rt"o~-,---------

~

_k

11101

:!:·

·:;

_r,_,_

-\:5

Cl1l

.

"'"

"'I'

'

L--

_..J

L

_______

_

Jstrations

Section

6

co•

0~

()ISTQQTOQ><

0/P

S~~

SKG

l

::

I

FHO&ACl

A•H

"'·I

,.,.

•.

anJ

••17

••10

~111

"''

•o

AMPLIFIER

(IR(UIT

!

~·

-I

""

Ant

~1'\

-4S

~

...

"'"'

An

...

IT(

A

....

-·~0~~--.~.~

..

~-----c

••

~.~

••

~~.~

..

~.~~.~

..

-.-.-,~----~

lQI$1

TR06)

TAIU

0111

OoU

METER

Clfi.CUI

I

"'ill

POWER

SUPPLY

CIRCUIT

r

AI&•

TIIIU

I .

..~

_t

~-,

ttl....

:::

!~n.~.~~

~

~~~=======i~·f·~~-~·=~~===j~-~'~

.__

,.

r--.

~

~::

·~

....

§5.i

....

r

r·

-1

:

~~~::"

'"

~

f''~

I

i•

•

f--1

.AIOoTHl

CI"CUFT

.OAAO

AU(-I.T

-

lltlJ

i

....

+--l-J+l---------1 l 'o•

""

""'

l,i

' L___'

"" ""

'""

~""

~

..

I:·

~-

..

:~"-_--

_

_._...J_'-_-_

-~L-_----'

__

"-_-T=

..

=t-=+_

,=_

G~u~,,~,_=_l'~'

....

_

-_-_-_-_--!:_==_==_==_==_=_=_=_==~~====~~=f--J.-;;,

..

;;;,;;;=d---t

I

I ' - - - - - - - - - - - -

--

-

--

_.,,_,__•

-

I , . ,

••

, ,

~

'

L';.'~"

~

. .

~,oe---·

I

"'

'1-

.

=-~~--,-----~~~~.·

i -

.·~·

.1:~--

~~-==-~--

=::====~"'====-======~·'

1:--

""'

~

,---<:':':j.--Li-1

.....

-

--

,----_-r--------r---_-_-_-_-_-

__

-

__

-_,-r---,-----;----f~.~-_,----~-~·;;;~-c::-o-1'

'

J;:r1.,.

1.,.

...

\;' •,

.1

"'

c:tJ

•"

d

~·

,-----1----------J

1:u

~

,i

"'

~

·:5

r---l

lc

._,,

~-

--~-----------~

...

,-L-, I

' ' L -

"'

•ouNTtD

CIAC\IIT

IOAOO

AISIIWILT

N•.

10011

.,

---------1.

6

.........

Ani

...

,

"'

'!.)_4

..

-,-01

'~

~·-;

c

'"

c

'09

''"

1CJJ

"'

'"

-

()I')

I

OIOJ

UoQ4

0•>•

'"

'"'

·~

Rl10AIJI

.',,

""'

AoH

"''l

""'

"'

...

..

,

"'

'"

...

'"

'"'

"'•

'"'

c

"'

'"

"'

c

~0

OIQJ

•••ot

:»o•

OtOI

!RoOT

TIIIOI

'"

WilT(

A

""'"'fD

''"'"''

~o<>•Ao

IIU-~T-

JltZJ

'"

....

"'"'

...

"'"

C•oJ

.....

"

'"'"

...

-

..

f:-

.....

ur

"'

,,

••u

...

UIU

TAou

•

114

....

•••o

""'

"'

...

,,

..

,,,,

,,

..

0111

o•n

··~

Oil)

DIU

...

Ill

,------,

METER

CIRCUIT

()'··

1

f.---J'~

I

.,

..

+

CIU

II.IU

I

.

I

J I

I

I I

'

I

0::.'"~'

L~t'J""

r:J-~+-"'~

~

....

'

r·

I

... ...

2~

~

Q

j...

..

~

...

;;,:.

~~~

~r---

1"''11

,J.,

r.

'"

r

! f

.,,.

••o

'"

-

"'

--.

.

I~

- I

'

~"'

OSCILL.TQA

'"IIHlO

CI.CUIT

IOA•O

oU~WILT

.....

1091\

.----,

I

,

-L

I

:

"'"

I

--

- - - - -

--

- - -

-i;-~:-

-

_J

+

...

..

"'

f"

+

JJV

OOOTU

1.(4

..OT

,ITT€0

Of< ...,_L UOU

J.

Cl

IS

A

~l...;T

..

o•

COOU.IAI

C

FOR

SERVICE

MANUALS

CONT/,CT:

MAURITAON

TECHNICAL

SERVICE/:

www

.mauritron.co.u\;;.

TEL: 01844 · .':\51694

FAX:

01844

·

352554

21

F1g.

5

Circuit

Otagram

Specification

FREQUENCY

Range:

10Hz

to

100kHz

in 4

decade

ranges.

Common

320°

circular

scale

for

all

ranges.Scale:

Setability:

To

1

part

in

10

4

Accuracy:

2%

of

reading

+

1HZ

Typically

1%

+1

HL

OUTPUTS

1)

MAIN

OUTPUT

30V

r.m.s.,

e.m.f.

(15-0-15V)

from

balanced floating

output

of

impedance

300-0-300

Ohms

(15V

r.m.s.

into

600

~!load).

Output

Impedance

tolerance:

5%-

Balance 3%

Balanced

Attenuator:

20dB and 40dB (60dB

total).

Accuracy:

0.3dB

and

0.5dB

respectively,

each

half.

Fine level

control,

from

0

to

full

output

(Common

to

Outputs

1,2 and 3).

2)

LOW

IMPEDANCE

OUTPUT

3)

41

3V

r.m.s.,

e.m.f.

from

approximately

1

Ohm.

With

Output

1

fully

loaded,

Output

2

will

deliver

a

typically

of

1

Watt

into

5

Ohms.

LOW

DISTORTION

OUTPUT

(at rear

of

instrument).

typically

2.5V

r.m.s.

from

approxir:1ately

5k

~!.

Overall flatness

0.3

dB.

SQUARE

WAVE,

0

to

+5V,

independently

controlled.

Source

Impedance

approximately

lk~!.

Rise

and

Fall

times

better

than

1>-<s

into

less

than

lOOp F. Mark-

space

ratio

better

than

1.1:

1.

NOTE:

Section

2 3

OUTPUT

LEVEL

METER

Scaled

0-30V

r.m.s.

Open

Circuit

for

Output

1.

Scale

also

common

to

Output

2.

Decibel

scale,

referred

to

+20dBm

into

600

il

The

meter

accuracy

is

3%

ofF

.S.D.

DISTORTION

1I

2)

Outputs

1

&2:

less

than

0.1%

above

100Hz

rising

to

less

than

0.5%

at

1OHz.

Typically

better

than

0.05%

from

200Hz

to

100kHz

Low

Distortion

Output:

Typically

better

than

0.02%

above

200Hz

rising

to

0.2%

at

10Hz.

PROTECTION

All

outputs

rated

for

full

load

simultaneously

All

outputs

Short-Circuit

proof.

Visible

indication

of

overload

on

Output

Level

Meter

(Intermittent

reading).

SUPPLY

VOLTAGE

85-130V

and

170-255V

40-400Hz,

approximately

20VA.

Also

42-52V

.

DC/300mA

Max.

OPERATING

TEMPERATURE

RANGE:

DIMENSIONS

27 x 27 x 13 ems 110.7 x 10.7 x 7.2 in.)

WEIGHT

6kg (131bs.)

All

outPut

levels

are

flat

within

ldB

over

the

full

frequency

range.

Below

30Hz

the

maximum

output

level

may

not

be

available

on

full

lead,

on

outputs

1 & 2

(typically

20V

available

at

1OHz).

FOR SERVICE MAI\IUALS

'

MAURITRON

T!?Cf!~ICAL

SERVICES

www.mauri"lron.co.uk

TEL:

0184A

351694

FAX:

01844-352554

4

Operation

3.1

SWITCHING

ON

(i)

Make

sure

that

the

voltage

supply

tap

on

the

transformer

is

set

correctly,

and

that

the

correct

fuse

is

used.

The

transformer

is

accessible

upon

removal

of

the

top

cover

of

the

instrument.

(see

5.1).

Unless

labelled

otherwise,

the

J3A

is

delivered

for

234V

+ 10%

(See Fig. 1

for

transformer

taps,

links

and

fuse ratirlgsl.

In

addition,

an

over-voltage

tap

(41V)

IS

available

on

the

secondary

Winding,

which

effectively

extends

the

range

of

effectively

extends

the

range

of

supply

voltage

to

-20%.

(ii)

Set

the

support/carrying

handle

to

the

required

operating

position.

The

handle is released

by

pulling

both

fixing

bushes

outwards,

and

it

can

then

be

turned

to

lock

in

any

one

of

three

positions.

(iii)

It

is

advisable

to

turn

the

Output

Level Fine

control

to

minimum

before

switch·on,to

avoid

large surge

outputs

for

the

few

seconds

that

the

oscillator

takes

to

stabilise.

(iv)

The

Instrument

is

ready

for

use

half

a m1nute

after

switching

on

and

fully

'settled'

within

five

minutes.

No

special

precautions

with

cooling

need

to

be

taken

normally

but

natural

ventilation

should

not

be

restricted

when

operating

at

high

ambient

temperatures.

3. 2

BLOCK

DIAGRAM

The

broad

outlines

of

the

instrument

are shown in

the

block

Diagram in Fig. 2.

Power

is

supplied

by

a Regulated

supply

which

includes

the

protection

circuits.

The

low

distortion

output

from

the

Wien

bridge

oscillator

of

variable

frequency

is

taken

through

a

front

panel

Fine

Output

Level

control

to

-

-II>--

'

POWER

SUPPLY, SERIES REGULATOR

EXT!:

D.C.

So

PROTECTION CIRCUIT

.--

--

9

0/P

+31V

POWER AMPLIFIER

WIEN

BRIDGE

0/P

0/P<r

-

OSCILLATOR

0/P

..

LEVEL

2-

l

Section

3

Fig. 1

Power

Supply

Tappings,

links,

and Fuse ratings

36V Secondary Tap.

195-230V

(170-210)

n;;,

255V

Figures in

brackets

refer

to

use

of

41V

secondary tap.

the

Power

Amplifier,

which

drives

the

transformer·coup!ed

power

outputs

and

the

Meter

circuitry.

The same

oscillator

drives a

Squarer,

the

level

being

adjustable

through

a second

front

panel

control.

L

i Mains METER

N

r-

CIRCUIT

e

r

-

II

<>

f-o300n

II

~

+22V

~

SQUARER

C.T

'--

f-oi/P

0/P()-

-

~

-

~

<>

f-o

JOOn

ATifNUATOR

2:--

~

l

CCNY

OISTORTK>N

0/P

LOW·Z

0/P

=-

O(P

Fig. 2

Block

Diagram

'

I

l

I

r

;

......

l

r

\

'

•

Operation

3.3

SELECTION

OF

FREQUENCY

To

set

frequency,

the

Range

Switch

is

turned

to

the

appropriate range.

The

fine

control

of

Frequency

is

a

circular

dial

which

is

set

at

the

desired

part

of

the decade

in

use.

Although

the

accuracy claimed on the dial calibration

is

typically

1%,

the

resolution

of

the

gang

capacitor

in

the

oscillator

is

essentially infinite and frequency can be

set

to

any required value

to

within

1:

10

4. It

is

often

convenient

to

use

the

independent

square

wave

output

to

monitor

the

exact

frequency

by

a

Timer

Counter.

3.4

BALANCED

OUTPUT

15·0·15V

r.m.s

.•

e.m.s.,

(i)

Output

1

is

mainly

intended

for making balanced

600

n'

line

measurements.

In

such use

the

desired

amplitude

is

set

on

the

Meter-

remembering

that

half

the

Open

Circuit voltage will

appear

across

the

load-

and

the

balanced

attenuators

are used to give

-7-

10

or...;..

100

facilities.

(i

i)

The

balanced

output

can be used unbalanced,

terminated

in 60011 ,

in

which

case Metering and

the

use

of

the

attenuators

is

exactly

as

above. If a low

level

unbalanced

signal from a

600

source

is

required

from

the

J3A-

i.e. less

than

-40dB-

it

is

advisable

to

use

half

the

balanced

output

with

the

centre

tap

at

the

low

impedance

end,

and

use a

300

resistor

in

series

externally

to

make

up

to

600

Q . This avoids

the

pickup

of

sma!l

spurious

signals due

to

the

unbalance

of

the

output,

which

can be significant

at

high

attenuation.

(iii)

Half

the

balanced

output

can also be used. If

terminated

with

300n,

again

the

Metering and use

of

attenuators

remain

unchanged,

but

of

course

only

half

the

output

voltage

is

being used, i.e.

the

output

is

a

quarter

of

the

e.m.f. indicated.

(iv)

In

addition,

the

balanced

output

can be used

in

any

of

the

above

ways

without

matched

termination,

i.e.

operated

into

any

load

between

open

and

short

circuit

It

would

then

behave like an e.m.f. with a source

impedance

of

600

or

300

n ,

depending

on

whether

the

whole

or

half

the

output

is

used. The

attenuators

remain

operative.

(v)

Finally,

there

is

no

reason

why

different

loads

should

not

be used

on

each half

output,

remembering

that

they

will be in phase

opposition,

and

the

resultants

either

measured

or

calculated.

(vi)

The

e.m.f.

from

the

bifilar

transformer

secondaries

is

essentially

balanced.

The

output

resistances

at

the

terminals

are

balanced

to

within 3%. Each

attenuator

may

introduce

unbalance

of

3%

in

e.m.f.,

but

the

unbalance

of

output

impP.dance remains unchanged,

at

a

maximum

of

3%.

Section

3 s

Warning:

1.

The

maximum

voltage applied

between

the

balanced

output

and

ground

must

not

exceed

500V

d.c.

or

peak

a.c.

2.

The

passage

of

direct current

through

~he.

balanced

output

must

be

restricted

to

less

than

50mA,

to

prevent

damage

to

the

output

resistors. A

muci"J

smaller

current

than

this, however, can

saturate

the

output

transformers-and

severely increase

distortion.

If

some

d.c.

must

be passed, it

is

an advantage

to

use

the

attenuators

which will effectively reduce

the

current

reaching

the

transformer

by

the

same ratio.

The

permissible d.c.

is

a

function

of

frequency

and

acceptable

distortion,

and can best

be

found

by

experiment.

3.5 LOW·Z OUTPUT

3V

r.m.s., e.m.f. Z0

<>1

Ohm

(i)

This can

be

used

unloaded,

and

the

e.m.f. can be read

as

1/1 Oth

the

Meter reading.

The

response

is

flat and

the

distortion

less

than

at

the

Balanced

Output.

The

full range

of

amplitude,

i.e.

3V

r.m.s.,

e.m.f.,

is

avail-

able when

output

2

is

loaded by 5 Q

or

more,

simultaneously

with

normal loading

of

output

1.

[f

cutput

1

is

unloaded

and

unattenuated,

the

load

on

output

2 can be generallv

reduced

to

3

Qat

full

output.

Loads smaller

than

3 Q may cause

the

protection

circuit

to

operate,

unless level

is

reduced.

Under

near

short

circuit

conditions

the

maximum

current

available

from

output

2

is

approximately

0.9A

r.m.s.

Below

30Hz

and

at

full

cutput/loading,

the

protection

circuit

may be

trigg~red

at

the

peak

of

a cycle.

Note

When

the

protection

circuit

operates

because

of

excessive loading,

the

output

level

automatically

'cycles

on

and

off'

at

intervals

of

about

2 seconds

This

is

indicated by a

corresponding

swing

on

the

output

Meter.

3.6 LOW

DISTORTION

OUTPUT

2.5V

r.m.s., e.m.f.

z0

<>5k

Ohm

(i)

This

output,

directly

from

the

oscillator,

is

taken

from

the

slider

of

the

Fine Level

Potentiometer

through

a

buffer

resistor.

It

can

be

loaded

without

detriment

to

the

performance

of

the

other

outputs,

although a

change

of

loading reflects

on

the

output

levels.

(ii) An

external

signal from

another

Generator

can be

injected

into

this

output

and

be resistively mixed

with

the

low

distortion

J3A

signal.

The

mixed

signal

is

then

available at. amplified

outputs

1 and 2

to

permit

intermodulation

measurements

on

amplifiers,

etc.

However, leads

left

attached

to

this

output

can pick

up and inject

unwanted

signals and noise

into

the

J3A.

60peration

It

should

be

noted

that

maximum

injection

occurs

with

the

Fine Level

control

at

its mid seuing.

Gould J3B User manual

Popular Portable Generator manuals by other brands