| 摘要 |
A system for polyphase encoding transmitted pulses of energy and for decoding the received signals to enhance returns from the range interval being examined during a particular processing period and attenuate returns from contiguous range intervals (pulse compression). The system includes a decoding device which comprises a delay circuit having N distributed outputs including its input for producing a uniform delay between adjacent outputs corresponding to N inputted elements of a received phase-coded signal of length N2; a conjugator circuit coupled to the first N/2 successive outputs of the delay circuit; a first signal-combining circuit coupled to the conjugator circuit and to the last N/2 successive outputs of the delay circuit; a multiplier circuit coupled to the first signal-combining circuit; and a second signal-combining circuit coupled to the multiplier circuit. The decoding device provides a decoding phase shift - DELTA phi k,p to the signal elements of the phase-coded signal wherein DELTA phi k,p=-(2 pi /N)[k-(1/2)(N-1)][p-(1/2)(N-1)] is the phase of the pth code element in the kth subgroup and k=0,1,2, . . . , N-1 and p=0,1,2, . . . , N-1, with N an even integer, and thereafter adds the phase-shifted signal elements at the same time to produce a narrow pulse with an accompanying increase in effective peak signal.
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