Duplexer - Furuno FM-8800D Service Manual

5.4.4 DUPLEXER

Duplexer is to be installed in FM-8800D. TX is composed in LPF and RX in HPF.
Estimated attenuation of effective frequency range for both from TX range to RX range
and RX range to TX range is approximately -60 to -70 dB. Since RX signal of simplex
channel attenuates in DUPLEXER, FM-8800D receives RX of duplex channels on DUP
RX board and RX of simplex channel on TX/RX board.
Rx RF
PA
SIMPLEX
(JUMPER)
TX FIL part (LPF)
- Frequency Range
- Insertion Loss
- Attenuation of Signal
RX FIL part (HFP)
- Frequency Range
- Insertion Loss
- Attenuation of Signal
TX/RX
05P0774
T/R
SW
J1 : DUP OUT
J2 : DUP IN 1
J4 : DUP IN 2
U2
J3 : ANT
Fig. 5.4.10 DUPLEXER Connection Diagram
: 156.0 to 157.5 MHz
: Within 1.8 dB
: 160.6 MHz/‐59.3 dB, 161.5 MHz/‐66 dB,
162 MHz/‐60.5 dB
: 160.6 to 162.1 MHz
: Within 1.8 dB
: 156 MHz/‐65 dB, 157.5 MHz/‐65 dB
DUP RX
(05P0777)
DUPLEXER
TX FIL
RX FIL
5-16
5.4 Block Description
R/T ANT
R/T ANT