一种改进的基于小波变换的包络提取算法研究

结合“模极大值小波域去噪”原理，提出了一种基于小波变换和希尔伯特变换的包络提取算法。首先用小波变换作为包络分析的前置处理手段，再利用希尔伯特变换对处理后的信号进行包络提取。针对希尔伯特变换解包络的不足，采用模极大值小波域去噪算法对包络信号进行消噪，从而解决了一般算法难以解决的由于随机噪声的干扰造成的提取的包络轮廓信息粗糙的难题。实验结果表明，该方法可以精确提取信号的包络并通过包络细化谱分析全面获得信号所隐古的故障特征。

Study on an Improved Envelope Extraction Algorithm Based on Wavelet Transform

Envelope analysis is an efficient approach to analyze the compound signal which is common in machinery fault signal.A novel denoising algorithm based on modulus maximum wavelet field is combined with Hilbert transform to present an envelope extraction algorithm based on wavelet transform.Firstly,the compound signal is decomposed in different frequency bands with wavelet transform and then the signal of needed frequency band is reconstructed,secondly,by Hilbert transform of the reconstructed signal the envelope information is extracted,thirdly,a novel denoising algorithm is introduced to overcome the limitation of Hilbert transform in which the extracted outline of envelope is rough which is resulted from the interference of random noises.The results of experiment show that this approach can extract the envelope information accurately and obtain the overall fault characters of signal efficiently.