An Implementation Method of Sub-Nyquist Sampling for Spectrum-Sparse Signals

Sub-Nyquist sampling based on Modulated Wideband Converter (MWC) as an innovative low rate sampling theory for sparse wideband signals draws much attention from researchers. However, the research in terms of implementation for this theory is far from satisfactory. In this paper, we present an implementation scheme for complete MWC sub-Nyquist sampling system. The proposed sampling system consists of two parts: a lower machine mainly designed by FPGA and four-quadrant analog multiplier, and an upper machine using computer. Lower machine is responsible for analog signal processing and sampling at a rate far below Nyquist rate, and the upper computer processes the acquired data and recovers the original signals. We exhibit experiment results from the designed system, especially provide waveforms of the pseudo-random sequences, mixed and filtered signals captured by oscilloscope. We give typical recovered results. Experimental results show that the proposed implementation method of MWC system can perfectly recover the original wideband signal from about 1/20 Nyquist rate data by MUSIC algorithm.