Abstract:

Nearfield holography (NAH) measurement usually needs discrete Fourier transform (DFT) for spectrum analysis. When the signal is sampled in a nonsynchronous manner, the DFT spectrum analysis will yield leakage errors, which will reduce the reconstruction precision. A method based on nonprior base analysis is adopted. The base vectors are determined through searching the maximum peak value of the inner product. The covering effect of strong signals can be decreased, and the result is more accurate. This method is introduced to the NAH measurement to analyze the complex sound pressure on the holography surface. After that, the radiation sound field of point source is reconstructed. The result shows that the accuracy of sound field reconstruction is improved.

Key words: acoustics, noise control, nearfield acoustic holography, nonprior base, sound field reconstruction, signal diagnosis

摘要：

在近场声全息(NAH)测量中，需要用离散傅里叶变换（DFT）进行频谱分析。在非同步采样下，DFT频谱分析产生泄露误差，导致重建精度低。基于非先验基的分析方法通过搜索内积的最大峰值来选取基向量，能够减小强幅值信号的掩蔽效应。将非先验基分析方法引入声全息系统，用来分析全息面复声压信号，进而重构点声源的辐射声场。结果表明，该方法能够提高声场重建的精度。

关键词: 声学, 近场声全息, 非先验基, 声场重建, 信号诊断