Eddins David A, Bero Eva M
Department of Otolaryngology, University of Rochester, Rochester NY 14642, USA.
J Acoust Soc Am. 2007 Jan;121(1):363-72. doi: 10.1121/1.2382347.
The present study investigates the nature of spectral envelope perception using a spectral modulation detection task in which sinusoidal spectral modulation is superimposed upon a noise carrier. The principal goal of this study is to characterize spectral envelope perception in terms of the influence of modulation frequency (cycles/octave), carrier bandwidth (octaves), and carrier frequency region (defined by lower and upper cutoff frequencies in Hz). Spectral modulation detection thresholds measured as a function of spectral modulation frequency result in a spectral modulation transfer function (SMTF). The general form of the SMTF is bandpass in nature, with a minimum modulation detection threshold in the region between 2 to 4 cycles/octave. SMTFs are not strongly dependent on carrier bandwidth (ranging from 1 to 6 octaves) or carrier frequency region (ranging from 200 to 12 800 Hz), with the exception of carrier bands restricted to very low audio frequencies (e.g., 200-400 Hz). Spectral modulation detection thresholds do not depend on the presence of random level variations or random modulation phase across intervals. The SMTFs reported here and associated excitation pattern computations are considered in terms of a linear systems approach to spectral envelope perception and potential underlying mechanisms for the perception of spectral features.
本研究使用一种频谱调制检测任务来探究频谱包络感知的本质，在该任务中，正弦频谱调制被叠加在噪声载体上。本研究的主要目标是根据调制频率（每倍频程的周期数）、载体带宽（倍频程）和载体频率区域（由赫兹的下限和上限截止频率定义）的影响来描述频谱包络感知。作为频谱调制频率的函数测量的频谱调制检测阈值会产生一个频谱调制传递函数（SMTF）。SMTF的一般形式本质上是带通的，在2至4个周期/倍频程的区域内具有最小调制检测阈值。SMTF并不强烈依赖于载体带宽（范围从1到6倍频程）或载体频率区域（范围从200到12800赫兹），但限于非常低音频频率的载体频段（例如，200 - 400赫兹）除外。频谱调制检测阈值不依赖于随机电平变化的存在或跨区间的随机调制相位。这里报告的SMTF和相关的激发模式计算是根据频谱包络感知的线性系统方法以及频谱特征感知的潜在潜在机制来考虑的。
