循环平稳声场的声源定位研究

旋转机械产生的辐射声场具有循环平稳特性,传统的平面近场声全息技术无法准确反映其调制特性,往往在边频带上出现虚假的能量的分布. 采用循环谱密度取代功率谱密度作为重建物理量,则可准确提取循环平稳声场的调制和载波信息. 考虑到循环谱密度的计算量以及特征提取的准确性,提出了循环谱密度组合切片分析法,并分析了加性白噪声对重建的影响. 仿真分析及实验结果表明,此方法有较强的噪声抑制能力,全息重建的结果可准确反映声源的位置. 关键词： 循环平稳声场 近场声全息 噪声源定位

Using delayed feedback to control the band of saturation control in an auto-parametric dynamical system

We investigate the band of the saturation control in an auto-parametric dynamical system by using the delayed feedback. In an original system without delay feedback, some unstable regions may occur in the band of the saturation control for some internal resonance detuning parameters. The band of the saturation control is distributed unreasonably. The delay feedback control is used to control the distribution of the band for saturation control. The effects of the gain and delay on the band of the saturation control are studied. The results show that the unstable regions of the saturation control can be eliminated by choosing the values of the gain and delay appropriately. Moreover, the bandwidth of the saturation control does not narrow. Consequently, the distribution band of the saturation control can be improved by using the delay feedback control.