说明：  针对提出的故障信号，利用awgn加噪，对其进行小波软硬阈值降噪，提出一种改进阈值，利用五种自适应阈值函数sqtwolog、rigrsure、heursure、minimaxi和ddencmp中阈值选取原则，对软阈值、硬阈值和改进阈值进行降噪效果对比。
(In view of the proposed fault signal, the wavelet soft and hard threshold de-noising is carried out by AWGN adding noise, and an improved threshold is proposed. The threshold selection principle of five adaptive threshold functions, sqtwolog, rigrsure, heursure, minimaxi and ddencmp, is used to compare the soft threshold, hard threshold and threshold value.)