汽车车外噪声声源特性分析与识别

Characteristics and Identification for Vehicle Pass-by Noise Sources

汽车车外噪声信号是非平稳信号,快速、准确地对其声源加以识别比较困难。提出了一种适用于非平稳信号的声源识别方法,利用二进正交小波包将信号无冗余、无疏漏、正交地分解到独立频带内,对车外噪声各声源信号进行特征提取,并应用多维线性方程组求解方法得到各声源对标准测点处噪声的贡献度。研究表明,该方法可揭示噪声信号在时频空间能量的细微变化,定量给出各声源贡献度。

Pass-by noise signal is non-stationary and time variant. It is difficult to identify sound sources accurately by the traditional FFT method. A new noise source identification technique was developed by using the wavelet packet transform. Firstly, the features of noise sources were extracted by the decomposition and reconstruction of the wavelet packet to time variant signals, and then, contributions were got from all kinds of the noise sources to the standard measuring point with the solving process of the multidimensional linear system of equations. Research showed that the technique could clearly distinguish noise energy change in the time-frequency domain and quantitatively identified noise sources.