Tx/Rx - Furuno FM-8800D Service Manual

4. TX/RX

4.1 PLL
This adjusts PLL circuit on TX/RX board. Frequency selected is set up as TX/RX
PLL frequency data.
１55.00 MHz
160.00 MHz
165.00 MHz
4.2 AGC
This is not in use. This is only equipped in case adjusting of AGC voltage and
checking AGC functions with "CHANNEL" knob or [▲] [▼] key. Voltage of
J9-#25 on TX/RX board will be changed by this adjustment but since normally this
is function is not in use, 1.1V is always the setup voltage and indicated as below.
1.10V – 3.65V
<■■
4.3 APC
This is not in use.
4.4 STATUS
This allows you to check the TX/ RX status as indicated below.
*** TX/RX STATUS ***
CH
RX IF LEVEL
RX AF NOISE
CH70 RX IF LEVEL
CH70 RX AF NOISE
PLL 1 UL LEVEL
PLL 2 UL LEVEL
EXIT : ENT
4.4.1 CH
Set up the channel to check with "CHANNEL" knob or [▲] [▼] key. The
channel mode is INTL.
** TX/RX PLL **
AGC Test out
> 1.65
EXT : EXT
SIMP 16
2442
18012
2442
18012
0
0
- RX 1st Lo frequency
Fo + 51.2375 MHz
- TX Lo frequency
Fo + 45 MHz
8-13
8.3 T/A, TEST, RESET DSP