Abstract：Wavelet transform is a new method that can he used to achieve part signal analysis simultaneously in time (or spatial) domain and frequency domain. Its major superiorities lie in good part characteristics in both time (or spatial)domain and frequency domain,as well as focusing attention to any signal details due to increasingly shorter time (or spatial)domain sampling step size for high frequency contents.In principle,any operation in which Fourier transform is performed can he replaced by the wavelet transform,without the limitation of short time window.This method consists of the steps:(1)forming scale function and wavelet function to obtain corresponding frequency response;(2) making"cone decomposition" of signals by Mallat's algorithm;(3) telling effective signals from noises according to their spectrum difference,and;(4)zeroing noises and acquiring signals by adopting Mallat's reconstruction algorithm.
