Abstract
An important issue in noise suppression of structures, machinery such as automobiles and aircrafts is found by the precise information on source locations and noise radiation characteristics and to work out the countermeasure plans effectively. In the point of view of noise reductions, noise source identification has to be the basic issue. Experiment data of Nearfield Acoustical Holography (NAH) include all kinds of noise. Therefore it is impossible to get precise result without removing noise. In this paper, the basic theory of discrete wavelet analysis and techniques to identify the multiple noise sources are investigated. And the validity of the system of NAH method are made sure by comparison of Hanning Window method with Fast Wavelet Transform (FWT).
