基于S变换的内燃机噪声信号时频特性

简述了S变换的基本原理,设计了仿真试验,对比分析短时Fourier变换与S变换的时频分析和信号检测能力.结果表明,S变换是一种更加有效的非稳态信号时频分析方法.以某六缸发动机为研究对象,采集机体前端和顶部噪声信号.采用S变换对噪声信号进行时频分析,分析信号能量在时频域内的分布规律及其频率成分随时间的变化情况,结合发动机的结构特点,分析噪声信号中比较突出的频率成分产生原因.S变换比较适合于发动机噪声信号时频特性研究,研究结果对发动机低噪声改进设计具有一定的参考价值.

Time-frequency characteristics of noise signals based on S transform for internat combustion engine

The basic principles of S transform were briefly discussed.The simulation experiment was conducted to compare the time-frequency analysis and signal detection capabilities of short-time Fourier transform and S transform.Comparisons show that S transform is a more effective time-frequency analysis method for non-stationary signals.Taking a six-cylinder engine as an example,noise signals from the engine front end and top surface were recorded.S transform was adopted to analyze the recorded noise signals in time-frequency domain.The energy distribution laws of noise signals and the variation of frequency components with time were subsequently analyzed.According to the engine structural characteristics,the generation cause of the more prominent frequency components was discussed.The analysis showed that S transform is more suitable for investigating the time-frequency characteristics of noise signals.