使用小波变换去噪，小波母函数选择 sym4 ,lev默认值为8,一般为8级小波去噪， par 为 CDF系数，通常取0.9，signal 列向量。取噪声信号范围，对分解的第lev层到第1层的高频系数进行重构。查看滤波后信号和噪声的小波分量-Wavelet transform denoising, the mother wavelet select ' sym4' , the lev default value is 8, is generally 8 wavelet de-noising, par for the CDF coefficient, usually taken 0.9 Signal column vector. Take the noise signal to be reconstructed on decomposition lev layer to the first layer of high-frequency coefficients. View the filtered signal and noise wavelet components