The reassigned smoothed pseudo wigner - ville distribution ( rspwvd ) is introduced , which has less interference and higher resolution than other time frequency distributions like wigner - ville , choi - williams etc . it is used to detect the multi - knocking of engine such as cylinder , piston pin , valve , crank bearing , connecting rod bearing and jib knocking . a new fault diagnosis technique based on the rspwvd for the engine multi - knocking problem is proposed . by comparing the bispectrum and bicoherence of the gear vibration signals , it is demonstrated that bispectrum has an advantage over bicoherence for feature extraction of such signals 第四章首次引入一种重分配方法，得到干扰项少而分辨率高的重分配平滑伪魏格纳维尔分布( rspwvd ) ；对发动机曲轴主轴承响、连杆轴承响、活塞销响、活塞敲缸响、气门响和挺杆响等常见机械异响故障振动信号特征进行了全面地比较分析；通过对各种异响故障特征信号的分析研究，提出基于rspwvd的发动机多异响故障诊断策略，利用该策略可以准确识别不同的发动机异响故障。
