This work reviews the human auditory system, elucidating some of the specialized mechanisms and non-linear pathways along the chain of events between physical sound and its perception. Customary relationships between frequency, time, and phase--such as the uncertainty principle--that hold for linear systems, do not apply straightforwardly to the hearing process. Auditory temporal resolution for certain processes can be a hundredth of the period of the signal, and can extend down to the microseconds time scale. The astonishingly large number of variations that correspond to the neural excitation pattern of 30000 auditory nerve fibers, originating from 3500 inner hair cells, explicates the vast capacity of the auditory system for the resolution of sonic detail. And the ear is sensitive enough to detect a basilar-membrane amplitude at the level of a picometer, or about a hundred times smaller than an atom. This article surveys and provides new insights into some of the impressive capabilities of the human auditory system and explores their relationship to fidelity in reproduced sound.
翻译:本文回顾了人类听觉系统,阐释了从物理声音到其感知这一链式事件中的一些特殊机制和非线性通路。通常适用于线性系统的频率、时间与相位之间的关系(如不确定性原理)并不能直接适用于听觉过程。对于某些过程,听觉的时间分辨率可达到信号周期的百分之一,并可延伸至微秒时间尺度。由3500个内毛细胞发出的30000条听觉神经纤维所对应的神经兴奋模式,其变化数量之惊人,揭示了听觉系统解析声音细节的巨大能力。耳朵的灵敏度足以检测到皮米级别的基底膜振幅,这大约比一个原子小一百倍。本文综述了人类听觉系统的一些令人印象深刻的能力,并提供了新的见解,同时探讨了这些能力与再现声音保真度之间的关系。