| 摘要 |
A satellite communications system includes a feed array and reflector receiving antenna coupled to a dual-mode network, for generating two channels, with independent signals representing two beams, one for each channel. Each output channel of the dual-mode network contains redundant information relating to a plurality of information channels. In the absence of an interfering signal or intrusion, the combined signals are amplified and block frequency-converted, then de-multiplexed into separate channels, which are each applied through selection switches to a transmitter multiplexer for retransmission. An alternate signal is tapped from each of the two received signal channels, phase controlled, and combined, to produce a combined signal representing a receive antenna beam with a null controllable in position in response to phase. The combined signal is demultiplexed into separate information channels. In the presence of an intrusion in one of the channels, the selection switch for that channel is set to an alternate position, in which the alternate signal is selected for transmission. Since the alternate signal includes a null in the receive beam, the position of the null may be set to the location of the intrusion signal to suppress the signal.
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