A Blind Demodulation Algorithm for MFSK Signals Using STFT-Radon-Wavelet Transform

A blind demodulation algorithm for MFSK (M-ary Frequency Shift Keying) was proposed in the paper. Firstly it exploited STFT to obtain the TFR(time-frequency representation) of MFSK signal. In addition, the Hough transform was applied to extract the modulation parameters, the number and values of carrier frequencies of MFSK signal. Secondly we got M WT plots through the Modified Wavelet transform based on the acquired parameters. Finally, we calculated the code width and demodulated the coding sequence of carrier frequencies according to the derived formulas of code width and hopping laws of modular peaks in WT plots. Extensive Monte Carlo simulation results indicate that the algorithm can complete the parameter estimation and signal demodulation under the premise of no prior information of 2FSK, 4FSK, and 8FSK.