循环谱密度组合切片分析在近场声全息中的应用研究

Application of cyclic spectral density gathering slice method to the near-field acoustic holography

为减小循环谱密度的计算量以及提高其特征提取的准确性,提出了组合切片法:取循环自相关切片的各峰值频率作循环频率分别计算循环谱密度切片,通过组合切片分析来确定声场信号的特征频率。然后采用循环谱密度取代功率谱密度作为平面近场声全息的重建物理量。实验结果表明,此方法可针对性的提取循环平稳声场的调制特性,全息重建的结果可准确反映噪声源的位置。

The need for reducing the computational complexity and improving the precision of feature extracting of the Cyclic Spectral Density （CSD）, the CSD gathering slice method was proposed, that is the peak frequencies of Cyclic Autocorrelation Function（CAF） slice are chosen as cyclic frequency to calculate a set of CSD slices and the feature frequencies of sound field signal are extracted by the CSD gathering slices. And the CSD, instead of the power spectrum of sound signal is adopted as reconstructed physical quantity in the planar near-field acoustic holography. The experiment results illustrate that modulation characteristics of cyclostationary sound field can be directly extracted and noise source can be exactly localized.