| 摘要 |
The retransmitter according to the invention is particularly designed to afford bidirectional radio beam links between a first station, such as a telecommunication relay station, and a plurality of mobile second stations, such as vehicles. It comprises two duplexers with filters 4, 4a connecting first and second unidirectional paths S1, S2 in the retransmitter to first and second antennas AS, AM directed towards the first and second stations respectively. Each path comprises a circuit 1, 2 for channel-by-channel filtering and for amplification. The amplification of the signals is carried out at the high transmission frequencies. In the direction of transmission S2 from the second stations to the first station, for each communication channel C21 to C2N, there is provided a noise attenuator and level limiter circuit 251 to 25N for minimising the cross-modulation between the various channels. <IMAGE>
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