小波分解重构，可以作为研究小波频率的一个重要参考，但是注意，该代码分解出来的高低频系数不能完全当作滤波器使用，只是参考。(Wavelet decomposition and reconstruction can be used as an important reference for studying wavelet frequency, but attention is paid to the high and low frequency coefficients decomposed by this code, which can not be used as a filter only.)