A Fast Nyquist Zone Index Estimation Algorithm for Pulse Radar Signal Based on Non-cooperative Nyquist Folding Receiver

Abstract

Nyquist folding receiver (NYFR) is a novel wideband receiving structure. The NYFR uses the non-uniform sampling to fold the monitoring bandwidth and the input carrier frequency is transformed into an added modulation parameter. The added modulation parameter is called as the Nyquist zone (NZ) index. Under the non-cooperative receiving condition, the NYFR outputs will become hybrid modulated signals because of the unknown NZ index. To simplify the signal processing of the NYFR, a feasible way is to estimate the NZ index directly without the prior information of the signal modulation types and demodulate the hybrid modulated signal using the estimated NZ index. In this paper, a fast estimation algorithm is proposed to get the NZ index directly. The basic pulse radar signals are considered and they are constant frequency signal, binary phase coded signal and linear frequency modulation signal. Compared with the existing algorithm, the simulation results demonstrate the merits of the proposed approach.