Sub-Nyquist sampling system for pulse streams based on non-ideal filters

Abstract

Recent developed finite rate of innovation (FRI) sampling framework provides an efficient way for sub-Nyquist sampling of pulse streams, which are widely applied to the fields of radar and wireless communication. Most researches of FRI sampling structure were implemented in hardware based on filter banks. However, the non-ideal effects of the filters would lead to low reconstruction accuracy. In this paper, we propose a two-channel sub-Nyquist sampling system for pulse streams, which significantly improves the reconstruction performance of the system under non-ideal filters hardware environment. The proposed scheme consists of two parallel sampling channels. The pulse streams and its basis signal are modulated and filtered with non-ideal low pass filters, followed by sampling at twice the cut-off frequency. By setting the cut-off frequency of the filter, the number of samples of different numbers is obtained, and the Fourier coefficients of the different frequency bands of these signals are obtained from the obtained samples. Such a technique allows for recovery of an arbitrary pulse with different frequency spectrum, which greatly improves the flexibility of the sampling system. Then we propose a joint parameters recovery algorithm to reconstruct the pulse streams, which can effectively eliminate non-ideal effects. Finally, we design a hardware prototype to verify the feasibility and effectiveness of the proposed system. Simulation and hardware experiments have shown that the proposed system greatly improves the signal reconstruction accuracy.