Ozimek E, Sek A
Institute of Acoustics, Adam Mickiewicz University, Poznań, Poland.
J Acoust Soc Am. 1987 Nov;82(5):1598-603. doi: 10.1121/1.395149.
This article discusses the detection of mixed modulation, i.e., simultaneous amplitude and frequency modulation (MM). The investigations have incorporated both a sine wave modulating signal and an irregular modulating signal, a very narrow noise band, of a specified center frequency. The results revealed that for a sinusoidal low-frequency modulating signal, amplitude and frequency changes that were separately subthreshold could be detected by listeners in mixed modulation. This indicates summation of sensations caused by simultaneous AM and FM modulation. This effect was not observed in the case of the irregular modulating signal. A hypothesis is advanced that the perception of modulated signals is governed by two mechanisms, viz., temporal and spectral. The operation of the two mechanisms depends mainly on the modulating frequency. The type of modulation does not play any significant role in this case.
本文讨论了混合调制的检测，即同时进行幅度和频率调制（MM）。研究中采用了正弦波调制信号和不规则调制信号，后者是具有特定中心频率的极窄噪声带。结果表明，对于正弦低频调制信号，听众能够在混合调制中检测到单独低于阈值的幅度和频率变化。这表明同时进行调幅和调频调制会引起感觉的总和。在不规则调制信号的情况下未观察到这种效应。有人提出一种假设，即调制信号的感知由两种机制控制，即时间机制和频谱机制。这两种机制的运作主要取决于调制频率。在这种情况下，调制类型没有起到任何显著作用。
