Dau T, Kollmeier B, Kohlrausch A
Carl von Ossietzky Universität Oldenburg, AG Medizinische Physik, Germany.
J Acoust Soc Am. 1997 Nov;102(5 Pt 1):2892-905. doi: 10.1121/1.420344.
This paper presents a quantitative model for describing data from modulation-detection and modulation-masking experiments, which extends the model of the "effective" signal processing of the auditory system described in Dau et al. [J. Acoust. Soc. Am. 99, 3615-3622 (1996)]. The new element in the present model is a modulation filterbank, which exhibits two domains with different scaling. In the range 0-10 Hz, the modulation filters have a constant bandwidth of 5 Hz. Between 10 Hz and 1000 Hz a logarithmic scaling with a constant Q value of 2 was assumed. To preclude spectral effects in temporal processing, measurements and corresponding simulations were performed with stochastic narrow-band noise carriers at a high center frequency (5 kHz). For conditions in which the modulation rate (fmod) was smaller than half the bandwidth of the carrier (delta f), the model accounts for the low-pass characteristic in the threshold functions [e.g., Viemeister, J. Acoust. Soc. Am. 66, 1364-1380 (1979)]. In conditions with fmod > delta f/2, the model can account for the high-pass characteristic in the threshold function. In a further experiment, a classical masking paradigm for investigating frequency selectivity was adopted and translated to the modulation-frequency domain. Masked thresholds for sinusoidal test modulation in the presence of a competing modulation masker were measured and simulated as a function of the test modulation rate. In all cases, the model describes the experimental data to within a few dB. It is proposed that the typical low-pass characteristic of the temporal modulation transfer function observed with wide-band noise carriers is not due to "sluggishness" in the auditory system, but can instead be understood in terms of the interaction between modulation filters and the inherent fluctuations in the carrier.
本文提出了一个用于描述调制检测和调制掩蔽实验数据的定量模型，该模型扩展了Dau等人[《美国声学学会杂志》99, 3615 - 3622 (1996)]中描述的听觉系统“有效”信号处理模型。本模型中的新元素是一个调制滤波器组，它呈现出两个具有不同缩放比例的域。在0 - 10 Hz范围内，调制滤波器的带宽恒定为5 Hz。在10 Hz至1000 Hz之间，假设采用具有恒定Q值2的对数缩放。为了排除时间处理中的频谱效应，使用高中心频率（5 kHz）的随机窄带噪声载波进行了测量和相应的模拟。对于调制率（fmod）小于载波带宽（delta f）一半的情况，该模型解释了阈值函数中的低通特性[例如，Viemeister，《美国声学学会杂志》66, 1364 - 1380 (1979)]。在fmod > delta f/2的条件下，该模型可以解释阈值函数中的高通特性。在进一步的实验中，采用了一种用于研究频率选择性的经典掩蔽范式并将其转换到调制频率域。测量并模拟了在存在竞争调制掩蔽器的情况下正弦测试调制的掩蔽阈值作为测试调制率的函数。在所有情况下，该模型将实验数据描述在几分贝的范围内。有人提出，在宽带噪声载波下观察到的时间调制传递函数的典型低通特性并非由于听觉系统中的“迟缓”，而是可以通过调制滤波器与载波固有波动之间的相互作用来理解。
