Application of wavelet transform in laser detection of underwater acoustic signal

Abstract

This article analyses the characteristic of time frequency distribution of laser detection signals of underwater acoustic signal, we discover the regularity of wavelet ridges distribution of laser interference signal: some wavelet ridges distribute on the scale-time curve which is corresponding with the frequency of underwater acoustic signal, or symmetrically distribute in the upper and lower sides. According to this regularity, a method for estimating the instantaneous frequency of underwater acoustic signal using wavelet ridges is put forward. Detection experiments of underwater acoustic signal with stable-frequency and the linear frequency modulation are both carried out using wavelet transform, and the results prove the correctness of this method.