| 摘要 |
A radar system having a radar transmitter and a radar receiver. The radar receiver includes a "local" receiving station and a "remote" located antenna station. A feedthrough nulling system is provided. The nulling system includes a "remote" combiner for providing an feedthrough null residual signal representative of the difference in power between a signal received by the antenna station and a feedthrough nulling signal. A "remote" downlink modulator, disposed at the antenna station, produces an optical signal representative of the feedthrough null residual signal. A "local" downlink optical detector, disposed at either the receiver station or the transmitter, detects the optical signal representative of the feedthrough null residual signal. A variable attenuator-phase shifter is fed by a signal from the transmitter and the detected optical signal representative of the feedthrough null residual signal and changes the gain and phase shift of the signal from the transmitter in accordance with the signal detected optical signal to produce a replica of the transmitted signal with proper gain and phase shift to null feedthrough signals received at the antenna station. An "local" uplink laser modulator, disposed at the receiver station or the transmitter, produces an optical signal representative of the replica of the transmitted signal with proper gain and phase shift to null feedthrough signals received at the receiving antenna station such fed signal. An "remote" uplink detector, disposed at the antenna station, detects the optical signal produced by the uplink laser modulator, and produces the feedthrough nulling signal. A "local" noise degeneration system is also provided.
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