Oxenham Andrew J, Shera Christopher A
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
J Assoc Res Otolaryngol. 2003 Dec;4(4):541-54. doi: 10.1007/s10162-002-3058-y. Epub 2003 Jul 10.
Auditory filter shapes were derived from psychophysical measurements in eight normal-hearing listeners using a variant of the notched-noise method for brief signals in forward and simultaneous masking. Signal frequencies of 1, 2, 4, 6, and 8 kHz were tested. The signal level was fixed at 10 dB above absolute threshold in the forward-masking conditions and fixed at either 10 or 35 dB above absolute threshold in the simultaneous-masking conditions. The results show that filter equivalent rectangular bandwidths (ERBs) are substantially narrower in forward masking than has been found in previous studies using simultaneous masking. Furthermore, in contrast to earlier studies, the sharpness of tuning doubles over the range of frequencies tested, giving Q(ERB) values of about 10 and 20 at signal frequencies of 1 and 8 kHz, respectively. It is argued that the new estimates of auditory filter bandwidth provide a more accurate estimate of human cochlear tuning at low levels than earlier estimates using simultaneous masking at higher levels, and that they are therefore more suitable for comparison to cochlear tuning data from other species. The data may also prove helpful in defining the parameters for nonlinear models of human cochlear processing.
听觉滤波器形状是通过对8名听力正常的受试者进行心理物理学测量得出的，采用了一种适用于前向掩蔽和同时掩蔽中简短信号的带凹口噪声方法的变体。测试了1、2、4、6和8千赫兹的信号频率。在前向掩蔽条件下，信号电平固定在绝对阈值以上10分贝；在同时掩蔽条件下，信号电平固定在绝对阈值以上10分贝或35分贝。结果表明，与之前使用同时掩蔽的研究相比，前向掩蔽中的滤波器等效矩形带宽（ERB）要窄得多。此外，与早期研究不同的是，在所测试的频率范围内，调谐锐度增加了一倍，在1千赫兹和8千赫兹的信号频率下，Q(ERB)值分别约为10和20。有人认为，与早期在较高电平下使用同时掩蔽的估计相比，听觉滤波器带宽的新估计在低电平下能更准确地估计人类耳蜗调谐，因此它们更适合与其他物种的耳蜗调谐数据进行比较。这些数据可能也有助于确定人类耳蜗处理非线性模型的参数。
