Description
2-37
1
2
3
4
5
2.4.5.3
Radio coupling function (duplexer)
The radio function is composed of:
• the LNA function to amplify the RX signal,
• the duplexer function (RX and TX filters),
• the insulator function to protect the PA against reverse inter-modulation,
• the Swrmeter function that provides an alarm during a fault on the antenna, with the
instruction:
- alarm if SWR > 4
- end of alarm if SWR < 2
Figure 2.12
RADIO COUPLING FUNCTION BLOCK DIAGRAM
RADIO COUPLING FUNCTION
CTL
RX out
ANT
TX in
LNA
RX
TX
30dB
50
Ω
Swrmeter
IDR-
IDO
_MC2_
F
O
NC_
RADIO
_S
Y
NO
P_
01_0
1
