Multi-resolution Analysis And Modulation Recognition Of Communication Signals

Multi-resolution analysis and modulation recognition of communication signals is the importance and fundamental research subject in modern electronic warfare and demodulation. The wavelet analysis a new effectual method in modem signals processing, it has characteristic and advantage of multi-resolution and multi-scale. Therefore, Based on the wavelet analysis is applied in communication signals analysis, multi-resolution analytic characteristic ,modulation parameter estimation and modulation classification of digital modulation signals is studied in the master thesis. The main work and obtained results can be summarized as follows:l.By expounding basic theory of wavelet transform and communication modulation signals, the wavelet transform features of typical modulation signals are analyzed on the time-scale plane in this paper. Furthermore, The optimum scale factors of different modulation types is deduce in detail.2.The carrier frequency have to be estimated to fix on scale's range of the wavelet transform on studying on modulation parameter estimation of MPSK signals in advance. Then, Based on the optimum scale factors locate the transients produced from phase changes, symbol rate of MPSK signals be able to be estimated. The separation between transients gives a symbol rate estimate. The accuracy of the estimator is 0.03% at SNR=-3dB,best.3.Different modulation signals have remarkably different wavelet coefficients features , their optimum scale factors corresponding with modulation types .Based on these characteristics, three classes modulation signals classifier is designed to classify 2/4/8ASK 2/4/8FSK and 2/4/8PSK signals, The simulation results proved the effectiveof the algorithm proposed in the thesis.4.Based on STFT, the transient characteristic of radio beacon response signals is presented, effectively, Furthermore, the transient characteristic will support automatic classification of different source signals.