Cadence ZRS C8 Instrukcje Operacyjne Pobierz pdf (Strona 87)

Band

frequency

and adjust

the

generator

output to

give

10-mrv

outpnt.

NoLe

the

signal

generator

ontput.

This

fig-

ure divided by 10

pv is

the

ratio

given

in

the table

belorv.

Signal Inrage

frequency

frequenc5

(mcl r

Dlc

I

loading

as the

modulating

frequencl-

is varierì.

Note

the

change

in

pou'er

output in

cll,r us

the

modulating

frequency

is varied. The

a-f r.e-

sponse

should be

flat within

3

db

from

1100

to

2,000

cps and within

7 db from 250

to 2,500

cps.

f

.

AVC

Characteristic.

Perform

this

test in

conjunction

with the

sensitivity

test

given

in rr

above.

With

the

PHN.-C.W.-NET-CAL.

su,'itch

52 in the PHN.

position, proceed

as

follorvs:

(1)

Set the

R.F.

GAIN control

at

maxi-

mum

clockwise

nosition.

Adjust

the

signal

generator

to suppll'

a

1.5-pv

signal, modulated

30

percent

at 400

cycles.

Adjust

the

receiver

A.F.

GAIN

con-

trol to

produce

a 10-mw

porÀ,'er

output.

An

increase

of

signal input

to 10

pv

should

not

produce

an

increase

in

power

output

of

more

than

15

db,

ancl

a further increase

in

signal input

to

10,000

pv should not

produce

an addi-

tional increase

in

power

output

of

more

than

3 db.

Image-

rejection

ratio

db

1

3

4

2.7

5.0

9.5

18

3.61

5.91

10.41

18.91

10,000

to

1

3,160 to

1

2,000 to 1

316 to

1

80

70

60

50

e.

Fi,clelity.

This is

a test of the

over-all

a-f

response

of the receiver.

Set the signal

gen-

erator to

5

mc,

modulated

30

percent

and with

the PHN.-C.W.-NET-CAL.

switch in

PHN.

po-

sition;

tune the receiver

to

the signal.

Adjust

the signal

output of the

generator

to 50 pv and

maintain

this

level throughout

the

tests.

Vary

the modulating frequency

from 250

to 2,500

cps;

use the internal

variable-frequency

audio

oscillator or an

external calibrated

oscillator.

Adjust

the

R.F.

GAIN

and

A.F.

GAIN controls

to

produce

a level

at

which

there

is

no over-

(2)

(3)

(4)

AGO 3134

79

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