5.4 Block Description
5-11
The 05P0774A is installed in FM-8800S and the 05P0774B is installed in FM-8800D.
Both of them have almost the same circuit and their difference is recognized by the
availability of DUPLEX input/output connector.
RX circuit converts a signal to 2
nd
IF and outputs it into CPU board.. TX circuit consists
of MIXER, PA, and APC circuit. PLL circuit is used for both TX and RX. However,
FM-8800D carries out DUPLEX RX on DUP RX board. The self-test of TX/RX PCB
detects Un-Lock/Lock signal by assessing the efficiency of PLL circuit of 1
st
Local on
this board. The specifications are below.
Table 5.4.3 Main Specification of TX/RX PCB
Item Specification
Antenna input/output (J3)
Impedance
50 ohm
RX frequency
Simplex: 155.000 to 163.600 MHz
Sem-Duplex: 155.400 to 158.000 MHz
160.000 to 163.600 MHz
Duplex: 160.600 to 162.100 MHz
1
st
RX
IF frequency 51.2375 MHz
2
nd
RX
IF frequency (RX IF OUT) 37.5 kHz, -60 to +10 dBm output
RX 1
st
Local frequency
Fo + 51.2375 MHz TP1 level: +4 to +6 dBm
VCO control voltage (TP2):
165 MHz: 4.5 to 6.2 V
155 MHz: more than 3.1 V
RX 2
nd
Local frequency 51.2 MHz (0 dBm, 50 ohm) TP4 level: +4 to +6 dBm
RX sensitivity Input level of SINAD 20 dB is below 0 dBuV
TX frequency
Simplex: 155.000 to 161.475 MHz
Sem-Duplex: 155.000 to 158.000 MHz
Duplex: 156.025 to 157.425 MHz
TX 1
st
Local frequency Fo + 45 MHz
Maximum TX output Over 40W (board output)
APC Controls from 0 W to the maximum
Maximum frequency division Within 5 kHz
Spurious Emission Less than 0.25 uW (9 kHz～2GHz)
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