Bruel & kjaer 1023 User manual

J

Bruel

&

Kjcer

r-

--~

-----"

"

1023

Sine

Generator

Valid

from

serial

no

.

739

1

57

037

-

0226

BROEL & KJA:R

Nrerum -Denmark

037-0226

Consisting of:

1023

Service

Instruction

Technical Description

Checking Procedure

Adjustment Procedure

ZD

0117

ZD

0118

ZE

0151

ZI

0032

Frequency Counter

Output

Circuits, Power Supply

Oscillator Circuits

810ck

Diagram

with

Parts List

1.79

Service

Instruction

1023

Sine Generator

Valid from serial no.

7391

57

page date

0-1

1.79

0-2

5.75

1-1

5.75

1-2

5.75

1-3

5.75

1-4

5.75

2-1

5.75

2-2

5.75

3-1

5.75

3-2

5.75

3-3

5.75

11.75

1

1.79

2

.79

1

1.79

2

1.79

4-1

1.79

Trouble

Shooting

If any

faults

should occur please check

the

instrument

according

to

the

procedure

outlined

below.

When

a

fault

has been traced and corrected,

the

voltages and adjust-

ments influenced by

the

correction

must

be

rechecked. The complete

in-

strument

should

then

be tested according to

the

Checking Procedure to

make sure

that

all basic

functions

are operative.

The tolerances given in these notes are intended

for

use as a guide for

adjustments.

Before correcting any apparent deviation make sure

that

the

measuring

instrument

has tolerances

small

enough

not

to affect the measurements.

Modifications

Due

to

the constant technical progress the

instrument

will

be modified

from

time

to

time

in

order

to

provide

continously

improved performance.

For

this

reason there may be small differencies

between

the

instrument

and

the

Service Instruction.

However, the local Representative Service is in possession of all informa-

tion

regarding the modifications

that

have been made.

Spare

Parts

Please state type and serial

number

of

the

instrument

when

ordering

spare

pa

rts.

0-1

o

()

(JI

()

2pes. Spes.

o

N

W

Ul

CD

:2

o·

CD

::J

!!l.

2

!l

o·

::J

In

BROEL &

KJA::R

Nrerum

-

Denmark

I

lzl

Modulation Frequency

Hz

tuning

On

Technical Description

1023.1

~

_________________________

~

0032

-,

Var.

Osc.

I

Z40

taZOO

kHz

Tl

..---------_01.1/5

;-

_____

.oIB;:..Z'---+-+o

modulation

Out

JZ

H2

FAZ

PZ-

-

--02

fva-;:-20-22Ok~~n-;3Vp-::p-

C2

Frequency Counter

ffix

10

kHz

TTL

-"---------'

Lin

Turn

Off

120

kHz

sine

Lo

g 240

to

200kHz

TTL

Lin:0,5mV/Hz

Otal0V

Log:

IV/Octave

-1

to

10V

~

__

. _ _

~O

2..

__

AA

3

_________

_

Compressor

General

I

---------

Off

Z 3

+15,4

v----f]

Off

Generator

The Sine

Generator

Type

1023

is a high

quality

signal source

which

covers a frequency range from

10Hz

to

20

kHz.

The

output

signal is produced by mixing a Fixed Oscillator Signal

of

120

kHz

with

a Variable Oscillator signal

of

240

to

200

kHz divided by

2.

The Fixed

Oscillator

signal is produced by a

4,88

MHz Crystal Oscillator

which

is divided by 61 and by 2 and

multiplied

by 3

after

which

the

120

kHz

signal

is applied to the Compressor

Amplifier

where

the ampli-

tude

of

the

signal is controlled by a

DC

voltage proportional

to

the Com-

pressor

input

signal.

The Variable signal is created by a Voltage Controlled Oscillator

with

a

frequency range

of

1,2

to

1 MHz

which

is divided by 5. In order

to

linear-

ize and stabilize the VCO, an

error

feed-back

arrangement

has been

made as explained

later

in the description.

The Variable Oscillator signal can have a

linear

or a logarithmic relation-

ship to

the

DC

tuning

voltage of 0

to

10V.

III Lin. mode the tuning

voltage is

0,5

mV

per Hz and in Log mode 1 V per octave

with

OV

at

20

Hz

and

thus

-1

V at

10Hz.

The

output

signal of the Generator can be modulated by applying a pul-

sating

DC

voltage to the VCO.

Modulation

frequencies

of

1 -

2,5

-

6,3

and

16

Hz

can be selected

while

the

frequency deviation is ±10%

of

the

center

frequency up

to

a

maximum

of

±

250

Hz

which

is remained con-

stant

from

2,5

kHz

to

20

kHz

center frequency.

The Block Diagram is extremely

helpful

in case of Trouble Shooting as it

contains

information

about signal levels and

waveforms

between the cir-

cuit

boards.

However,

there

are a

cCJuple

of

circuit

details in the

instrument

that

need

a

further

discussion:

5.75

Valid from serial no.

523774

1-1

1023.1

Technical Description

Modulators

Two

different

types of

modulators

are being used

in

the

instrument.

The

drawing

shows

the

type

which

is used

to

provide

20

to

220

kHz

for

the

Frequency

Counter

and

for

the

Frequency

to

Current

Converter

for

stabi-

lizing and correcting

the

linearity

of

the

VCO.

f1

is applied to

the

base

of

Vl

which

acts as an

ordinary

amplifier

stage

as long as

V2

is

turned

ON by a negative f

2.

When

V2

is

turned

OFF by a positive f2.

Vl

will

not

transfer

any signal

at

all

to

the

output.

In

this

way

f1

will

be chopped

by

f2'

and

V3

and

V4

are

inserted

to oper-

ate in

the

same

way

as

Vl

and

V2

thus

creating a balanced

modulator.

Also

the

Constant

Level

Output

Modulator

ZM

0200

which

can be con-

nected to

the

Fixed and Variable Osc.

outputs

is of

this

type,

where

a sta-

bil

output

amplitude

can be obtained as a

fixed

amplification

is deter-

mined by

the

ratio

between

RC

and

RE.

The next

drawing

shows

a

more

sophisticated type

than

the

It

is used

to

mix

the

fixed and variable

oscillator

signals

in order to

produce

the

final

output

signal

of

the

instrument.

The demands here are

low

noise,

extremely

low

distortion

and a band-

width

on the

output

from

10Hz

to

20

kHz.

Servo

Loop

for

VCO

In

order to

obtain

a

frequency

change

proportional to

tuning

voltage as

well

as a

high

frequency

stability,

a feed-back

arrangement

has been

made.

From

the

Frequency

Tuning

potentiometer

a

positive

current

is applied

to

an Integrator

the

output

of

which

is used

to

tune

the

Voltage Controlled

Oscillator.

The

1,2

to 1

MHz

output

signal

from

this

oscillator

is mixed

with

a fixed

frequency

of

1,22

MHz

thus

producing

a signal

from

20

to

220

kHz.

A Frequency

to

Current

converter

supplies a

current

proportional

to

fre-

quency, and it

now

appears

that

the

VCO

will

be

tuned

to

a

frequency

which

causes

the

negative

current

output

from

the

converter

to be ex-

actly

the

same value as

the

positive

tuning

current.

Frequency

to

Current

Converter

The basic

definition

of

this

converter

is

that:

Current

i = charge Q x Frequency f and

charge Q = Capacitors C x Voltage

V.

This indicates

that

the

stability

of

the

system is

given

by

the

charge Q

which

is created

by

means

of

a

very

stabil ref. voltage V

of

-10

V and a

number

of capacitors

C,

which

are

of

different

temperature

coefficient

for max. stability.

1-2

+Ub

-Ub

450mV

ff

ix

-p W

450mV

p-p

400mV

LF

f

yor

TTL

Freq. Tuning

Integrator

1,22

MHz

-10Vref.

V

---~'"'

charge discharge

III

Freq Tuning

~

C

(temp.

comp.)

0-10V

5.75

The

input

frequency

f is applied

to

a Voltage Comparator

which

pro-

duces

the

square wave signal

a.

When

this

signal is at

OV

the capaci-

tors C are being charged to the ref. voltage

of

-lOV.

A charge 0 is

now

available

on

the

capacitors, and a

moment

later a dis-

charge is stated by means of

the

signal

C.

Each charge 0 supplies a certain

current

into

the Integrator and

the

total

current

will

be

proportional to the frequency f.

Lin.lLog

Converter

When

the

instrument

is in Log position, a

Lin.lLog

converter is inserted

between

the

tuning

potentiometer and the VCO.

As

it

appears

from

the simplified diagram, a

number

of transistors are

connected

in

a

row

with

a reference voltage applied to

the

bases. This

reference voltage is increased

by

approx.

0,5

V steps up

the

row,

and

the transistors

will

now

be

turned

on

as

the

Lin.

input

voltage is in-

creased.

In

this

way

a a parabolla is formed like

shown

on

the

diagram, yet hav-

ing

18

steps instead of 3,

thus

providing a good approximation

to

a

true

log curve.

In connection

with

the Lin

.I

Log Converter, a

temperature

compensating

circuit

is used.

V342

is acting as a temperature detector as

the

forward

voltage across

it

is

temperature

dependent. The voltage drop across

V342

is amplified by

V357,

the

resulting

signal being present across

R356.

By means

of

R342

+

355

is

now

to

the

Linear

input

voltage added a volt-

age

which

is proportional

to

the

forward

voltage across

V342

and

thus

temperature compensated.

a

-IS,4V

b

-IOV

a

c

-IS,4V

+ref.

Lin

5.75

Valid from serial no.

523774

Technical Description

1023.1

Lin

input

Log

t----

.....

---

..

Log

out

1-3

1023.1

Technical Description

Frequency Counter

With

"Counting

Time"

positioned at 1 s

the

principle

of

operation is as

follows:

A Preset sets the Decade Counters

to

8000,0

after

which

the Gate is en-

abled and the Control Time Base disabled.

As

the

Counting Time Base is

actually a

10000

divider the Gate

will

be enabled for 1 s.

On

the trailing edge of impulse no.

10000

the Gate is disabled and

the

Control Time Base enabled. Impulse no.

10001

generates a Transfer sig-

nal

which

leads

the

results

from

the

Decade Counters

out

to

the

7-Seg-

ment Display

through

BCD

to

7-Segment

Decoders/Drivers.

The

trailing

edge

of

pulse no.

10003

produces a Preset, and

the

whole

procedure is

repeated.

When

the Decade Counters have been Preset

to

8000,0

instead

of

0000,0

it

is due

to

the

fact

that

a Gate

input

of

20

kHz should read 0

Hz

and

220

kHz

should

read

20

kHz.

And

20

kHz

during

1 s provides exactly

20000

pulses

which

sets the Decade Counters

to

0000,0.

If

f. inst.

the

Gate

input

is

70

kHz,

the

number

of pulses

during

1

swill

be

70000

of

which

the

first

20000

are used

to

set

the

Decade Coun-

ters

to

0000,0

so

the

final

result

will

be

5000,0

Hz

on

the

Frequency

Display.

When

"Counting

Time"

is

at

0,1 s the counting period is

100

ms only

and the Decade Counters

will

be Preset

to

98000

instead.

"Counting

Time"

1 s is possible up

to

approx.

9500,0

Hz

only at

which

frequency a

Time

Base Cross-Over

Circuit

on

ZI

0032

automatically

switches to

"Counting

Time"

0,1 s.

Blanking

Logic

With

"Counting

Time"

at 0,1 s digit 1 is blanked

when

it

reads 0 and di-

gits 2, 3 and 4 are blanked

when

they

read 0 and

when

the more signifi-

cant digit is already is blanked.

At

1 s

"Counting

Time"

only

digits

1, 2 and 3

will

be blanked

if

they

are

o

thus

leaving the

two

least

significant

digits on all

the

time.

All

digits are blanked

when

the frequency is

tuned

out

of range.

Frequency Marking

By means of a

"Frequency

Marking"

selector on the rear panel

it

is possi-

ble to choose marking intervals controlled by

digits

2,

3

or

4.

Outputs from the respective latch are applied to a

Monostable

Multivibra-

tor in the Frequency

Marking

Circuit.

An

inverted and

non-inverted

input

is used to ensure

that

changes

in

both directions

will

trigger

the

Mono-

stable

which

has an

aoutput

impulse of approx.

10

ms.

On the "Frequency

Marking"

socket on the rear panel a

10

ms signal

will

be provided each

time

the

selected

digit

is changing, and a perma-

nent

signal is provided

whenever

the

digit

is

O.

This

output

can f. inst. be used

to

activate

the

"Event

Marker"

of

a Level

Recorder and in

this

way

plot a non-calibrated paper.

There is a

24

V sensing

circuit

which

allows

Frequency

Marking

only

when

a Level Recorder is driving.

1-4

~01

c: c:

.,.-

".:.:

er'-

.,

0

'-~

"-

Count/Stop

Preset/

Transfer

Enoble

Control

Time Bose

Counting Time

=:J'--

___

S_t_o-'-p

__

--'F

Isec.

---

LJLnJ

Transfer

______

~r-l~

____________

__

Preset

5.75

T

,

BROEL & KJA:R

Nrerum

-

Denmark

Ext. 121

Menuel

Lin

=O,SmVtHz 0

to

10V

lo.~

1V!OchlV@ 1

to

10V

Compressor

V31

Moduletion

Freq.

Hz

tuning

Lin

Log

,",,'

:t

Checking Procedure

1023.2

On

ZI 0032

_

~2_

-------

----

_

---

___

I

Ver.

Osc.

240

to

200 kHz

162

.---

_______

~Xl/S~----"9:"----..--~

modulation

TTL

1

!A2

FA2

Pi

----02-

fVOr20-:i20kH-;~n-;3Vp-p-

--

---

-

C2

-

--

-

---

ffix

10

kHz

TTL

Frequency

Counter

120

kHz

sine

Turn

Off

I'll

240

to

200

kHz TTL

I

1

Power 5upp

ly

I

1

_______________

-

__

-

_____________

I

ZE

0151

Fixed

Osc.

-~

120 kHz sine

150

mV

RMS

Load

-~

Generator

Generator:

"On"

Ref. Signal:

"Off"

Sweep Control:

"Manual-Log"

Compressor Speed:

"Off'

Output

Voltage:

"5"

Modulation

Frequency:

"Off"

Output

Attenuator:

"Load"

Counting Time:

"1

s"

rear Frequency Range

Adj.

"Full"

Ref. Signal

to

"On"

Ref. Signal

to

"Off"

Sweep Control

to

"Manual-Log"

5.75

Set Frequency Dial

to

exactly

10Hz

and adjust Scale

Alignment

for

10.0

Hz

on

the

Digital

Frequency Display.

The Display should

now

correspond to

the

position

of

the

Frequency Dial

within

a tolerance

of ±3% of reading

through

the

whole

range.

At

approx.

9500,0

Hz

the

Counting Time is

automatically

changed

to

"0,1

s"

and the deci-

mal

point

disappears.

With

Sweep Control in

"Lin."

mode

the

accuracy between Frequency Dial and Display should

be ±

200

Hz

through

the range.

The Frequency Display should

now

read between

970

and

1030

Hz.

Turn

Frequency Dial

out

of range and check on the

Meter

that

the

Output

signal disappears

and

that

the Frequency Display is blanked.

Connect an RMS reading

Voltmeter

to

"Load"

and adjust

Output

Voltage

for

10

V RMS at an

output

frequency of approx.

1000

Hz.

The

1023

Voltmeter

should

now

read

full

scale ± 2%.

Reduce

Output

Voltage

to

a reading

of

f. ins!.

-2

dB and check the frequency response

to

be

within

±

0,2

dB referred

to

1

kHz

from

10Hz

to

20

kHz.

Turn

Output

Volta~

to

read

10

V RMS deflection

on

the

1023

Voltmeter

at a frequency of

1 kHz.

Connect a

150/10W

resistor

to

the

"Load"

terminals

and check

that

the

output

voltage

does not drop more

than

0,2

dB.

Increase

Output

Voltage and check

that

the

Distortion lamp comes on

at

an

output

voltage

of

. approx.

11,5

V RMS

into

150

corresponding to

an

output

current

of

0,76

ARMS.

Valid

from

serial no.

523774

2-1

1023.2

Checking Procedure

Generator to

"Off'

Compressor Speed to

"30

dB/s"

Compressor Speed

to

"10

dB/s"

Compressor Speed to

"Off"

Modulation

Frequency to

"1

Hz"

Modulation

Frequency

to

"16

Hz"

2-2

Disconnect the

15

n resistor and check the distortion

with

a Frequency Analyzer like f.

inst.

Type

2010.

With

10

V RMS on

"Load"

output the second and third harmonics should remain

at

least

60

dB

below

10

V corresponding to

0,1%

of

distortion. (At frequencies from

20

Hz to

20

kHz,

and

0,15%

at

10Hz).

The remaining noise on

"Load"

output

should be at least

70dB

below

10V

RMS.

Connect

"Load"

output

to the

input

of a

Voltmeter/Amplifier

and AC

output

of

the

Voltmeter

to

"Compressor

Input"

on

1023.

Adjust

Output

Voltage

for

a

19dB

deflection on the

10V

range

of

the

Voltmeter/Amplifier.

Adjust

Compressor Voltage for the same 19 dB deflection corresponding to 0 dB compres-

sion,

When

increasing the

amplification

of

the

Voltmeter/Amplifier

by

10

steps

to

60dB,

the de-

flection on the

Voltmeter/Amplifier

should

remain

at

19

dB.

At

60dB

of

compreSSion the noise

from

the Compr.

Amplifier

will

cause a

slight

instable

reading

which

can be avoided by using a selective

Voltmeter/Amplifier.

Select

60

dB

of

compression.

When

the plug

for

"Compressor

Input"

is taken out, the

Voltmeter

on 1

023

will

move

slowly

up

to

a final deflection

of

approx.

-1

dB, at it should take 4

to

5 s

to

reach

this

final deflec-

tion.

Connect an Oscilloscope (Time Base

0,5

ms)

to

monitor

the

output

signal

from

1023

which

should be

tuned

to appr

lX.

1000

Hz.

The Oscilloscope should

now

show

a sine wave signal

which

is changing in frequency + and

-10%

referred

to

the

center

frequency of

1000

Hz.

The ± 10% frequency deviation should remain

but

with

a

much

faster repetition.

5.75

BRUEL & KJA:R

Nffirum

-

Denmark

Power:

"On"

Output

Voltage

to

"0"

Ref. Signal:

"Off"

Sweep

Control:

"Manual-Lin."

Modulation

Frequency:

"Off'

Counting

Time:

"0,1

s"

rear

Freq. Range Adj.:

"Full"

5.75

Adjustment Procedure

1023.3

If any

adjustment

is

found

necessary

the

voltages

from

the

stabilized

power

supply

should

be

checked as these are a basis

for

correct

adjustment.

However,

it

should

be taken

into

consideration

that

if

the

+

15.4

V

supply

is adjusted a

com-

plete

adjustment

procedure

of

the

item Frequency and Scale

must

be carried

out.

In

many

other

cases as

well,

adjustment

of

one

circuit

will

cause

the

necessity

of

other

ad-

justments.

Therefore

the

procedure is parted

into

main

sections

with

a

certain

order

which

must

be

followed

in

adjustment

as

well

as knob positions.

Throughout

the

measurements

the

common

lead

should

be connected to

ground

as close to

the

measuring

point

as

possible

in

order

to avoid

errors

due

to

currents

in

the

ground

wiring.

It should be noted

that

components

with

100

numbers

will

be

found

on Frequency Counter

ZD

0118,

200

numbers

on

Oscillator

Circuit

ZI

0032,

300

numbers

on

ZE

0151

while

all

400

numbers

are chassis

mounted.

DC

VOLTAGES

Remove top and

bottom

plate

of

the

instrument,

but

leave

the

circuit

boards

in

place.

-19V:!:O,6V

no

adjustment

o 0

Mains

Transformer

+19V±O,3

V l&mV

±2mV

(see

text)

Check +

19

V ±

0,3

V and

adjust

P306

if

necessary.

-lS,4V!O,3V

no

adJ

ustment

Check

--19

V ±

0,6

V (no

adjustment

possibility,

but

affected

by

+

19

V).

Check +

15.4

V ±

30

mV

and adjust

P307

if

necessary.

Check

-15.4

V ±

0,3

V (no

adjustment

possibility,

but

affected by +

15,4

V).

Check + 5 V.±

0,25

Von

the

supply rail on

the

Frequency

Counter

board.

Connect

the

Voltmeter

to

the

two

resistors as

shown

and

adjust

P305

if

necessary for

16

mV

± 2

mV

(avoid a

common

ground

connection

between

1023

and

the

Voltmeter).

Connect the

Voltmeter

to

the

"Load"

terminals

and

adjust

P304

for

0 V ±

10

mV.

FIXED AND VARIABLE OSCILLATORS

The Fixed

Oscillator

is Crystal

controlled

and

not

adjustable,

while

the

Variable Oscillator is a

voltage controlled

LC

oscillator

where

the

adjustment

of

L

determines

only

the

range

of

the

oscillator. and

not

the

output

frequency and stability.

Thus

the

following

procedure

for

adjusting

the

range of

the

VCO

should

be used

only

if

a

fault

has been repaired

in

one

of

the

two

oscillators.

Position

the

instrument

on its

right

end

with

the

front

towards

the

operator and

ZI

0032

swung

out

on

the

table.

Connect

a Frequency Counter

to

"Fixed

Osc."

socket on

the

rear

panel and

chec~

the

fre-

quency

to

be

120

kHz ± 5 Hz.

Turn

P208

fully

clockwise

(from

component

side)

in

order

to enable a Frequency Display be-

low

5Hz.

Connect

a DiWital

Voltmeter

to

ES2

point

on

ZI

0032.

Turn

Frequency Dial

down

to approx. 0

Hz

on

the

Lin. Scale, and

fineadjust

for

0 - 2

Hz

on

the

Digital Frequency Display (Use Scale

Alignment

for

fineadjustment).

The

DVM

should

now

read 8 V ±

50

mV

and

if

not

adjust

L201

from

the

bottom

side

of

ZI

0032

to

such a

position

where

8 V ±

50

mV

is

obtained on

the

DVM

with

0 - 2 Hz on the

Digital Display. (Fineadjust Frequency Dial and Scale

Alignment

if

necessary).

Valid

from

serial no.

523774"

3-1

BRUEL & KJAER 1023 User manual

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