INTENSITY ANALYSIS BY THE WAVELET TRANSFORM AND ITS APPLICATION FOR THE MEASUREMENT OF TRANSMISSION OF SOUND THROUGH THE PANEL

Takaaki Musha (Japan) and Tatsuya Kumazawa (Japan)

Received February 16, 2008

Abstract

Conventionally, sound intensity analysis for stationary signals is conducted by using the Fourier transform, but this method cannot be applied for analysing non-stationary signals. Instead of the Fourier transform, the wavelet transform can be applied for analysing non-stationary signals. In this paper, an advantage of the intensity analysis by using the wavelet transform for analysing non-stationary signals is presented. We also present the application of the wavelet intensity analysis for the measurement of a transmission loss of the panel structure in the water. From the wavelet intensity analysis of experimental results, it is seen that the transmission loss for obliquely incident waves to the panel structure can be measured, which is difficult to be measured by the conventional single hydrophone method.

Keywords and phrases: instantaneous sound intensity, wavelet transform, transmission loss.