Verweij C, Rodenburg M
Audiology. 1977 May-Jun;16(3):241-51.
Responses of the guinea pig cochlea to amplitude-modulated stimuli were measured with the aid of a gross electrode. The dynamic characteristics of this part of the auditory system was studied by varying several parameters of the applied signal. The signals used as carriers in our experiments were either white noise or pure tones of 1 and 4 kHz. The modulation frequency, dynamic and intensity characteristics were determined by varying the modulating frequency, the modulation depth and the intensity of the applied signal. To get an idea about possible non-linear aspects of the system under investigation, we always computed the Fourier transform of the response data and plotted the amplitude of the various harmonics and the phase of the fundamental separately as functions of the signal parameter in question. The greatest response was always found at a modulation frequency of about 200 Hz, with a relatively gradual rise up to this frequency and a sharper drop above 200 Hz. The phase of the fundamental changes very rapidly at frequencies above Hz. The distortion is mainly second-harmonic and has a maximum about 1 octave lower than the fundamental. The carrier frequency and the intensity of the stimulus were not found to have a great influence on the frequency characteristic. For small modulation depths, the system is nearly linear; at higher intensities and modulation depths saturation occurs, coinciding with a relative increase in the intensity of the second harmonic with respect to the fundamental.
借助粗电极测量了豚鼠耳蜗对调幅刺激的反应。通过改变所施加信号的几个参数，研究了听觉系统这一部分的动态特性。在我们的实验中用作载波的信号要么是白噪声，要么是1kHz和4kHz的纯音。通过改变调制频率、调制深度和所施加信号的强度来确定调制频率、动态特性和强度特性。为了了解所研究系统可能存在的非线性方面，我们总是计算响应数据的傅里叶变换，并分别绘制各种谐波的幅度和基波的相位作为相关信号参数的函数。最大响应总是在约200Hz的调制频率处发现，在该频率之前上升相对平缓，在200Hz以上下降更陡。基波的相位在高于该频率时变化非常快。失真主要是二次谐波，其最大值比基波低约1个倍频程。未发现载波频率和刺激强度对频率特性有很大影响。对于小调制深度，系统几乎是线性的；在更高强度和调制深度时会出现饱和，同时二次谐波相对于基波的强度相对增加。
