Sampling LFM Signal with Stretch Processing based on Finite Rate of Innovation Method.

Linear frequency modulation (LFM) signals exist widely in many engineering applications, such as radar, sonar, wireless communications, and electronic reconnaissance, where stretch processing is commonly adopted to reduce the processing bandwidth. In this paper, a method of sub-Nyquist sampling and parameter estimation of LFM signals is proposed based on the stretch processing and FRI sampling theory. The method first mixes the received LFM signal with its delayed version. Then, the mixed signal is filtered by the FRI sampling kernel and sampled at a low sampling rate. Finally, the parameters of the LFM signal are estimated from the low rate samples. Theoretical analysis proves that at least 13 low rate samples are needed to estimate the amplitude, time delay, time width, chirp rate, and initial frequency parameters of the LFM signal. Theoretical analysis and simulation prove the effectiveness of the proposed sampling structure and method.