Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom.
J Acoust Soc Am. 2010 Oct;128(4):2150-61. doi: 10.1121/1.3478773.
The intelligibility of sentences processed to remove temporal envelope information, as far as possible, was assessed. Sentences were filtered into N analysis channels, and each channel signal was divided by its Hilbert envelope to remove envelope information but leave temporal fine structure (TFS) intact. Channel signals were combined to give TFS speech. The effect of adding low-level low-noise noise (LNN) to each channel signal before processing was assessed. The addition of LNN reduced the amplification of low-level signal portions that contained large excursions in instantaneous frequency, and improved the intelligibility of simple TFS speech sentences, but not more complex sentences. It also reduced the time needed to reach a stable level of performance. The recovery of envelope cues by peripheral auditory filtering was investigated by measuring the intelligibility of 'recovered-envelope speech', formed by filtering TFS speech with an array of simulated auditory filters, and using the envelopes at the output of these filters to modulate sinusoids with frequencies equal to the filter center frequencies (i.e., tone vocoding). The intelligibility of TFS speech and recovered-envelope speech fell as N increased, although TFS speech was still highly intelligible for values of N for which the intelligibility of recovered-envelope speech was low.
对尽可能去除时间包络信息处理后的句子的可理解度进行了评估。句子被过滤到 N 个分析通道中，每个通道信号都被其希尔伯特包络除以，以去除包络信息，但保留时间精细结构（TFS）不变。通道信号被组合以提供 TFS 语音。在处理之前，评估了向每个通道信号添加低水平低噪声（LNN）的效果。添加 LNN 减少了包含瞬时频率大偏移的低电平信号部分的放大，提高了简单 TFS 语音句子的可理解度，但对更复杂的句子没有帮助。它还减少了达到稳定性能所需的时间。通过测量由 TFS 语音过滤的一系列模拟听觉滤波器形成的“恢复包络语音”的可理解度，研究了通过外围听觉滤波恢复包络线索的效果，并使用这些滤波器输出处的包络来调制频率等于滤波器中心频率的正弦波（即音调声码器）。随着 N 的增加，TFS 语音和恢复包络语音的可理解度下降，尽管对于恢复包络语音的可理解度较低的 N 值，TFS 语音仍然具有很高的可理解度。
