为了澄清畸变产物耳声发射(DPOAE)产生源的机制,本研究首先采用固定刺激声频率比,交替加抑制声和对没有抑制声作用下的DPOAE信号进行分解的方法进行对比研究,得出DPOAE的产生源至少具有两个或两个以上,并具有不同的产生性质的初步结论。在此基础上,采用固定刺激声频率f2和扫描刺激声频率f1,逐步改变抑制声强度的方法。结果证明:DPOAE信号是由双源产生的,并且分别具有两种不同的性质。位于刺激频率f1和f2的最大交叠区且靠近f2位置处的产生源是主要的源并具有非线性相位的性质,产生具有较短潜伏期的信号。位于2f1-f2频率附近有另外一个产生源,该源产生的DPOAE信号具有线性相位性质,并具有较长的潜伏期。耳道中检测到的DPOAE是由两个不同的源所产生的DPOAE信号之和。
This paper studied the generation source mechanism of the distortion-product otoacoustic emissions (DPOAE). Firstly, two methods were used for comparing. One method was fixing the stimulus frequency ratio and the suppresser tone was presented alternately. The other one was decomposing the DPOAE signal without suppressor tone. The essential results showed that there are at least two generation sources for the DPOAE signal and with two different characteristic. Secondly, on the basis of these results, the paradigm of fixing the stimulating frequency and sweeping stimulating frequency, changing the level of the suppressor tone was used. All results supported the following hypothesis that the DPOAE was generated by two sources and with different characteristic separately. The main source locating at the region of the interaction area of f1 ,f2 and near the f2 peak had nonlinear characteristic and with short latency. Whereas, the source locating closely to 2f1 -f2 has linear characteristic and longer latency. The DPOAE measured in the ear canal were generated by two different sources and mechanism.