Icom IC-RP1620 Service Manual page 29

6-3
TX PLL ADJUSTMENT
Example of setting N-data for transmitting
Transmit frequency : 150.000 MHz
PLL reference frequency : 0.005 MHz (5 kHz)
N-data for
-
transmit frequency
transmitting- PLL reference frequency
150.000
= -
0.005
= 30000
ADJUSTMENT CONDITIONS
Set the transmit frequency
(See below): 150.000 MHz
Connect the RF power meter or a
50 f2 dummy load to the [TX A N 1
connector.
Transmitting
Set the transmit frequency
(See below): 150.000 MHz
Connect the RF power meter or a
50 f2 dummy load to the [TX ANT]
connector.
Transmitting
ADJUSTMENT
Transmit frequency
:
150.000 MHz
PLL reference frequency
: 0.01 25 MHz (1 2.5 kHz)
2
LOCK
VOLTAGE
REFERENCE
FREQUENCY
N-data for
-
transmit frequency
transmitting- PLL reference frequency
150.000
= -
0.0125
=
12000
After adjustment, program the identification frequency.
VALUE
8.5 V
150,000,000 Hz
ADJUSTMENT
POINT
MEASUREMENT
1
1
Set the dip switches (S9, S10) to the values
equivalent to the obtained N-data.
UNIT
TX
(T-VCO)
TX
UNIT
TX
(T-VCO)
Rear
panel
Example of setting the dip switches.
SO
$10
ADJUST
C1
R24
LOCATION
Connect the DC
voltmeter to R15.
Loosely couple the
frequency counter to
the [TX ANT]
connector.
S4
s9
$10
12.5 kHz
Dip N-data
switches value
S10-5
- +
16384
S10-4
- +
8192
S10-3
- r
4096
S10-1
-+
1024
S9-9
+
256
$96
- +
32
S9-5 16(+
Total 30000
Dip N-data
switches value
S10-4
- +
8192
S10-2
4
2048
S10-1
- +
1024
S9-10
+
512
59-8
+
128
S9-7
- +
64
S9-6
- +
32(+
0
L0GIC.A UNIT
TX UNIT
Total 12000
Setting
N-data for-
transmitting
T-VCO UNIT
C1
Lock voltage
adjustment
R24
Reference
frequency
adjustment
R15
Lock voltage
check point