A Digital Demodulation Method for Amplitude Modulated Signal Based on Sub-Nyquist Sampling

摘要

Digital demodulation technology confronts the pressure from sampling rate due to the wide bandwidth of radio transmission. The recent development of compressive sensing theory enables sub-Nyquist sampling. In this paper, we utilize an implementation approach of sub-Nyquist sampling--Modulated Wide Converter (MWC)--to demodulate a given frequency band from multiband signal of radio transmission. The paper analyzes the behavior in frequency domain of MWC sampling and reveals the essence of sampling process as spectrum segmenting. Considering demodulation of multiband signal, we optimize the spectrum segmentation through choosing optimal parameters for MWC to reduce the impact of nonideal analog lowpass filter. The numerical experiments demonstrate that the MWC with the improved configuration can eliminate the impact of analog filters and achieve perfect demodulation performance.