Abstract: The interior noise of a car in different conditions is tested according to our national standards. Using Fourier transform, the spectrum analysis is done for the signals and the critical frequency is obtained. It is found that in rapidly accelerating conditions, Fourier transform can only yield overall trends of the interior noise variation, and the detailed information cannot be obtained. Then, the “adaptive changes” time-frequency window structure of wavelet transform is used to gain the details of the signals and more frequency information.

Key words: acoustics, car interior noise, noise test, Fourier transform, wavelet analysis

摘要： 依据国标规定，对某车车内噪声进行测试。利用傅立叶变换对在不同转速工况下测得的噪声信号进行频谱分析，得到其关键频率。在对急加速工况分析的过程中发现虽然傅立叶变换可以分析出整体的变化规律，但不能得到其细节信息。由此采用小波分析对其进行补充，利用小波变换的“自适应变化”的时频窗结构得到信号的细节，并加以处理得到更多的频率信息。

关键词: 声学, 车内噪声, 噪声测试, 傅立叶变换, 小波分析