12
PT4200
SERVICE MANUAL
6.3.6 DCS TX Signal Wave Shape and Frequency
Adjustment
Under the computer test mode, select
DCS wide band
modulation
and click
adjustment
to enter
Adjust the
potentiometer VR1, and watch the demodulation signals. The wave
shape should be smooth (close to square wave) and then adjust the
figure to set the frequency deviation at 0.35kHz.
6.3.7 CTCSS Frequency Deviation Adjustment
Under the computer test mode, select
CTCSS wide band
modulation
, and click
adjustment
to enter. Adjust the figure to
set the frequency deviation at 0.35kHz.
6.3.8 Receiver Sensitivity
Repeat adjusting L9, L10, L6, and L5 to make the frequencies
at highest sensitivity.
6.3.9 Receiver Squelch Setting
Under the computer test mode, select
the 9th squelch
and
click
adjustment
to enter. Input the receiver with the signals of
1kHz modulation frequency, 3kHz frequency deviation, and -
117dBm level. Adjust the figure to make the green light flash.
Under the computer test mode, select
the 1st squelch
and
click
adjustment
to enter. Input the receiver with the signals of
1kHz modulation frequency, 3kHz frequency deviation, and 124dBm
level. Adjust the figure to make the green light flash.
6.4 Debugging
The above debugging refers to Table3, Table4, and Table 5.
Table 6.3 Voltage Controlled Oscillator (VCO)
Table 6.4 Receiver
Band
Pass
Filter
Spectroan-
alizer/
Item
Test
Condition
Test
Equipment
Test
Point
Adjustment
Part
Require
-ment
Note
Setting
Battery
Power:
7.5V
Multimeter
PD
Locked CH:RX Low
Frequency
C180 1.0V
0.1V
CH:TX Low
Frequency
C181 1.0V
0.1V
Watch
Adjust
-ment
Digital
Power
Item
Test
Condition
Test
Equipment
Test
Point
Adjustment
Part
Require
-ment
Note
Compreh
-ensive
Test
Device
Before
Mixing
Computer
Test
ModePass
Band
25MHz,
smooth
wave
Shape
Not
recom-
mend
the user
to adjust
it!
Audio
Level
Ch: RX
center
frequency
RF OUT
-53dBm
(501
V)
MOD:1kHz
DEV:
3.0
(kHz)
Audio
Load:16
RF Audio
Signal
Generator
Oscillator
Audio
Voltmeter
Distortion
Test Device
/Comprehe
nsive Test
Device
Speak
er
Conne
ctor
(Turn the
volume
knob
clockwise)
Audio
power
0.3 W
Inner
speake
r power
1.2W
High
Frequency
CH:RX
Lower
than 3.5V
Lower
than 3.5V Watch
Adjust
-ment
CH:TX High
Frequency
Item
Test
Condition
Test
Equipment
Test
Point
Adjustment
Part
Require
-ment
Note
CH: MF
Sensit
ivity
CH:LF
CH: HF
RF OUT:
-116dBm
(0.35
V)
MOD:1kHz
DEV:
1.5kHz
(W/N)
RF Audio
Signal
Generator
Oscillator
Audio
Voltmeter
Distortion
Test
Device
/Comprehe
nsive Test
Device
Speak
er
Conne
ctor
Computer
Test Mode
SINAD
12dB or
higher
Ch: RX
Center
Frequency
Squel
ch
Activa
tion
Sensit
ivity
Computer
Test Mode
After
adjustmen
t, squelch
activation
is normal.
Computer
Test Mode
9th
RF OUT:
-117dBm
After
adjustment,
squelch
activation
is normal.
1st
RF OUT:
-124dBm
Item
Test
Condition
Test
Equipment
Test
Point
Adjustment
Part
Require
-ment
Note
Table 6.5 Transmitter
TX
Frequ
ency
Frequency
Meter/
Comprehe
nsive Test
Device
Anten
na
Computer
Test Mode
Within
±
200Hz
Power
Power
Meter/
Comprehe
nsive Test
Device/
Ammeter
Computer
Test Mode
Adjust to
4W
Within
200H
z
±
Maxim
um
Modul
ation
Frequ
ency
Deviati
on
CH: TX
Center
Frequency
AG:1kHz/
70mV
Frequency
Deviation
Meter/
Comprehe
nsive Test
Device
Adjust to
±
4.5kHz
±
200
Hz
Modul
ation
Sensiti
vity
AG:1kHz/
7mV
Checking
frequency
deviation:
2.2kHz~
3.6kHz
Wave
shape is
close to
smooth
square
wave.
DCS
Wave
Shape
(Balan
ce)
Oscillator /
Comprehe
nsive Test
Device
Vr1
Содержание PT4200
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