畸变产物耳声发射信号的时域分离算法研究

Research of time-domain component separation of distortion product otoacoustic emissions

针对在分离畸变产物耳声发射(Distortion Product Otoacoustic Emissions,DPOAE)不同产生源成分的过程中两成分之间存在交叉干扰的问题,建立了IFFT(Inverse Fast Fourier Transform,IFFT)结合时域窗的成分分离算法模型,结合模型进行了分离误差的分析,并在此基础上给出一种时间窗窗宽选择准则。根据IFFT后的时域波形,利用两成分主峰包络内的信号波形的矩心移动速率的快慢选择两成分之间的合适的分界点,将两成分分离开。对结合了该时间窗窗宽选择准则的时域成分分离算法进行了仿真,并对DPOAE实验数据进行了成分分离。仿真和实验结果表明,结合该窗宽选择准则的DPOAE时域分离算法可以成功地分离两个成分,且有效地减少了因两成分之间的交叉干扰引入的幅度和相位扰动。因此,结合该窗宽选择准则的DPOAE时域分离算法是有效的,可以提高分离不同产生源成分的准确性。

In order to reduce the degree of cross-contamination between the two components of distortion product otoacoustie emissions （DPOAE） during separation, a time-domain separation algorithm model based on inverse fast fourier transform （IFFT） combined with time window was built and separation error was analyzed, based on which a window duration selection method was proposed for the separation algorithm. According to the time-domain waveform after IFFT, the centroids of the waveform under the two main peaks of the signal envelope were caculated. Then selection of a suitable separation boundary between the two components was identified according to the movement speed of the summed centroids to separate them. Simulation of the separation algorithm combined with the window duration selection method was done and DPOAE data from experiment was seperated. Simulation results and actual DPOAE seperation show that the separation algorithm combined with this method can also separate the two components successfully and greatly reduces the amplitude and phase disturbance caused by cross-contamination between the two components. Therefore the component separation algorithm combined with the window duration selection method is effective and it improves the separation accuracy.