Modulation Identification of Digital Signals Based on Wavelet Transform
Xiaoqiu Liu · Telecommunication Engineering · 2006
Wavelet transform(WT) is suitable for detecting transient signals.Instantaneous features of digital signals will be presented when the symbols change.This paper discusses the wavelet transform of the signals with and without the amplitude normalization,then extracts the ratio of the variance to the square of mean as the key feature,and finally an artificial neural networks(ANN) classifier is proposed to identify three digital modulation signals: ASK,FSK and PSK.Simulations show that the algorithm is very effective at low SNR of 5 dB.