BRUEL & KJAER 1022 - Page 13

BRUEL & KJAER 1022

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10

0

/o

0.5

5 0.2

0

~

0.1

0

Gl

10.05

z

---

=

Typical

Distortion

Curves

------

•

Guaranteed

Upper Limit

I

~02

®1+-------------~------------~----------~~-------

10

100

--Frequency

1000

10000

f

C/s

16107,2

Fi

g.

1.3.

Distortion

c

uw

es for d

iff

e

rent

loads.

Tlw

curve

marked

"Att.

10 volts"

is

obtained

from

·

measurem

e

nts

taken

on

the

ATTENUATOR

OUTPUT

terminals

open

circuit.

A

fifth

position

of

the

switch

MATCHING

IMPEDANCE

is

marked

"Alt."

and

connects

the

output

transformer

to

an

attenuator,

variable

in

steps

of

10

dB

from

120

,

ftvolts

to

12

volts,

and

is

operated

by

the

switch

marked

ATTEND-

A

TOR

on

the

front

panel.

With

the

impedance

sw

itch

in

this

position

the

output

circuit

is

connected

to

the

sc

re

e

ned

socke

t

on

top

of

the

front

panel,

the

output

impedance

being

constan

t

and

approximately

50

ohms.

The

overall

accuracy

of

the

attenuator

is

approxima

t

ely

2

%.

The

voltage

on

the

output

terminals

is

indicated

by

a

vacuum-tube

voltmeter

which

measures

the

average

value

of

the

A.F.

voltage.

It

is

calibrated

in

r.m.s.

va

lue

s

of

a

sinusoidal

voltage,

and

the

accuracy

in

the

frequency

range

20'-20ooo

c/s

is

1.5 %

of

full

scale

deflection.

In

addition

to

the

voltscales

there

is

also

a

dB

scale,

and

the

scale

is

ca

librat

ed

in

such

a

way,

that

it

is

possible

to

read

directly

the

level

in

dB

re.

1

volt.

The

sensitivity

of

the

voltmeter

is

automatically

changed

when

the

position

of

the

switch

marked

MATCHING

IMPEDANCE

is

altered.

Full

defle

c

tion

of

the

meter

is

indicated

on

the

switch.

When

the

MATCHING

IMPEDANCE

switch

is

in

position

"Att."

the

output

voltage

available

from

the

Oscillator

will

depend

on

the

position

of

the

A

TTENU

A

TOR

switch,

in

this

case

full

deflection

of

the

meter

corresponds

to

the

value

indicated

by

the

sw

itch

position.

11