CT Systems Wavetek 2500 - Page 46

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3.4.6

CTCSS

Decoder

Sensitivity

Test

This

test

determines

the

amount

of

subtone

deviation

that

is

required

to

un5quelch

the

CTC88

decoder

of

a

receiver

under

test.

Refer

to

Piqure

3-8

for

the

following

test

procedure.

1)

Connect

the

RF

input

(antenna

port)

of

the

receiver

under

test

to

the

"RF IN\OUT"

jack

on

the

Model

2500.

2>

Select

GEN

mode

and

set

the

RF

output

level

well

above

the

receiver

squelch

threshold.

3)

Select

AUDIO

SYNTH

mode.

4)

Set

the

audio

synthesizer

to

the

subtone

frequency

in

Hz

using

the

numerical

keys

followed

by

the

Enter

key.

5)

Put

the

receiver

under

test

into

the

decode

mode

and

adjust

its

squelch

for

threshold.

6)

Turn

off

the

audio

synthesizer

by

toggling

the

AUDIO

SYNTH

key.

7)

Activate

1 kHz

and

adjust

level

to

3 kHz

deviation.

8)

Toggle

AUDIO

SYNTH

back

on.

9)

Starting

:

at

minimum

audio

synthesizer

deviation,

slowly

increase

the

synthesizer

deviation

until

the

decoder

unsquelches

the

receiver.

10)

The

audio

synthesizer

deviation

at

this

point

is

the

d~coder

sensitivity.

2500-MANUAL

PAGE

34

SECTION-3