Rosen S, Baker R J
Department of Phonetics and Linguistics, University College London, UK.
Hear Res. 1994 Mar;73(2):231-43. doi: 10.1016/0378-5955(94)90239-9.
An important aspect of auditory nonlinearity is that psychoacoustically measured auditory filters broaden as the level at which they are measured increases. However, it is not yet clear whether the change in filter shape is controlled primarily by the level of the probe or that of the masker. We have therefore developed a new method for fitting filter shapes to notched-noise data in which filter parameters depend explicitly on signal level (either probe or masker). By applying this technique to a set of notched-noise data in which both fixed-probe and fixed-masker paradigms have been used at a range of levels, we have been able to show that models in which filter parameters depend on probe level are considerably more successful than models in which filter parameters depend upon masker level. The results from this new procedure have enabled us to describe the nonlinear changes in auditory filter shape at 2 kHz with only five parameters. Also discussed are the implications of these findings for the generation of excitation patterns and for the computational implementation of simple, yet reasonably realistic nonlinear auditory filters whose shape depends on their output.
听觉非线性的一个重要方面是，通过心理声学测量得到的听觉滤波器会随着测量时的声级增加而变宽。然而，滤波器形状的变化主要是由探测音的声级还是掩蔽声的声级控制，目前尚不清楚。因此，我们开发了一种新方法，用于将滤波器形状拟合到带噪数据中，其中滤波器参数明确依赖于信号声级（探测音或掩蔽声）。通过将该技术应用于一组带噪数据，在一系列声级下使用了固定探测音和固定掩蔽声范式，我们能够表明，滤波器参数依赖于探测音声级的模型比滤波器参数依赖于掩蔽声声级的模型要成功得多。这个新程序的结果使我们仅用五个参数就能描述2 kHz处听觉滤波器形状的非线性变化。还讨论了这些发现对激发模式的产生以及对形状依赖于其输出的简单但合理逼真的非线性听觉滤波器的计算实现的影响。
