讲述了现在机械故障诊断中用到的常用时频分析方法，如短时fft 魏格纳维尔分布 小波变换 HHT等，里面含有例子和详细说明，对初学者帮助很大。-Tells the now commonly used in mechanical fault diagnosis frequency analysis methods, such as short-time wavelet transform fft Wigner distribution HHT Louisville, etc., which cont