Saberi K
Massachusetts Institute of Technology, Research Laboratory of Electronics, Cambridge 02139, USA.
J Acoust Soc Am. 1998 May;103(5 Pt 1):2551-64. doi: 10.1121/1.422776.
Interaural-delay sensitivity to high-frequency (> or = 3 kHz) sinusoidal-frequency-modulated (SFM) tones is examined for rates from 25 to 800 Hz and depths of -12 to 18 dB. Comparison is made to thresholds obtained for sinusoidal-amplitude-modulated (SAM) tones for the same observers and modulation rates. Both SAM and SFM threshold-by-rate functions are U-shaped with optimum sensitivity to SFM tones occurring at higher rates (fm = 200-400 Hz) compared to those for SAM tones (fm = 100-200 Hz). Effects of modulation depth were examined for rates from 50 to 300 Hz. In all cases thresholds improved considerably with increasing modulation depth. It is also shown that a hybrid dichotic signal composed of an SFM tone presented to one ear and an SAM tone to the other, can perceptually fuse and be lateralized, with the contingency that both stimuli have equal modulation rates but not necessarily equal carrier frequencies. Using bandpass noise to restrict off-frequency listening, it was shown that for this stimulus, observers can use information from filters either below or above the carrier frequency. Consistent with FM-to-AM conversion from cochlear bandpass filtering, several important differences between the SAM- and SFM-tone data can be predicted from a nonstationary stochastic model of binaural interaction whose parameters are uniquely determined from the SAM-tone data.
研究了在25至800Hz的速率和-12至18dB的深度下，对高频（≥3kHz）正弦频率调制（SFM）音调的双耳延迟敏感性。将其与相同观察者对正弦幅度调制（SAM）音调获得的阈值进行比较。SAM和SFM的阈值-速率函数均呈U形，与SAM音调（fm = 100-200Hz）相比，SFM音调在更高的速率（fm = 200-400Hz）下具有最佳敏感性。在50至300Hz的速率下研究了调制深度的影响。在所有情况下，阈值都随着调制深度的增加而显著改善。研究还表明，由呈现给一只耳朵的SFM音调和呈现给另一只耳朵的SAM音调组成的混合双耳信号可以在感知上融合并被侧向化，条件是两个刺激具有相等的调制速率，但载波频率不一定相等。使用带通噪声来限制偏离频率的聆听，结果表明，对于这种刺激，观察者可以使用来自载波频率以下或以上滤波器的信息。与从耳蜗带通滤波进行的FM到AM转换一致，可以从双耳相互作用的非平稳随机模型预测SAM和SFM音调数据之间的几个重要差异，该模型的参数由SAM音调数据唯一确定。
