线阵波束形成声强缩放方法估算声源的辐射声功率

为了解决波束形成声源识别过程中声源辐射声功率定量计算的问题,给出了阵型简洁、便于组合的线阵声强缩放模型。通过推导线阵的声强缩放系数,建立起线阵波束输出结果与声源辐射声功率之间的换算关系。无论是线阵还是平面阵的声强缩放方法,对于偏离阵列中心位置较远处的声源进行辐射声功率估算时都存在较为明显的误差。通过理论推导和仿真模拟计算,研究了同一单极子点声源在不同位置处的声功率估算偏差随频率、幅度的变化规律,发现该估算偏差只与声源偏离位置有关,而与声源自身的强度信息无关的结论,据此给出了相应的声功率估算修正方法。半消声室实验结果和声压法测量结果对比表明:修正后的线阵声强缩放方法用于中高频声源的辐射声功率计算时,单频声源的估算误差不超过1.0 dB,宽带声源的估算误差不超过1.8 dB。 

Estimation of the radiated sound power by linear array beamforming sound intensity scaling method

A sound intensity model was proposed which is constructed by concise linear array.The quantitatively calculation for radiated sound power can be implemented by the proposed model in the process of sound source identification by using beamforming technology.The sound intensity scaling factor in the linear array was deduced,and the conversion relation between the outcomes of the linear array beamforming and the radiated sound power was further established.For both linear array and planar array,it exists obvious error in estimation of radiated sound power by using sound intensity scaling method when sound sources are located far distance from the center of the array.By using theoretical derivation and simulation calculation,the variation of sound power estimated error for the single monopole point source at different positions was investigated with various frequency and amplitude.It can be concluded that the estimated deviation is only related to the position of the sound source rather than the intensity information of the sound source.The corresponding correction method was proposed accordingly.By comparison between the experimental results of semi-anechoic chamber and the measurement results of sound pressure method,it shows that the developed sound intensity scaling method based on the linear array can be used to calculate the radiated sound source power in medium and high frequency range.The estimated error is limited in 1.0 dB for single frequency sound source,and 1.8 dB for wideband sound source.