Analysis of the acoustic signal backscattered by a multi-layer structure with the spectrogram and the wavelet time-frequency methods

Abstract

National audienceThis study is to discuss the efficiency of two different methods, time-frequency representations and frequency spectral method, by comparing their ability to analyse experimentally received signals backscattered by two types of multilayer structures. We will present a study of the propagation of acoustic waves backscattered by two multilayer structures with a resonant plate "aluminum or glass" and a less resonant plate "plexiglas" separated by a water layer. The backscattering experiments have been performed in a water immersion tank. The wavelet transform and the spectrogram time-frequency representations are used in this work. The images obtained by these representations are compared to the frequency spectral method. The results obtained by the time-frequency analysis are interesting