Moore B C, Glasberg B R, Stone M A
Department of Experimental Psychology, University of Cambridge, England.
Scand Audiol Suppl. 1993;38:82-91.
This paper describes two experiments in a series evaluating and optimising a hearing aid incorporating two forms of automatic gain control (AGC). The first form is a front-end AGC which is normally slow acting and which compensates for variations in the overall level of speech from one situation to another. The second form of AGC follows the front-end AGC. The signal is split into two frequency bands, and fast-acting AGC is applied in the upper band only. The bands are then recombined. The two experiments described here were aimed at determining the optimum value of the recovery time of the AGC in the high-frequency channel. Speech reception thresholds (SRTs) were measured in the presence of speech-shaped noise as a function of the recovery time, for subjects with mild-to-moderate sensorineural loss. In the first experiment the recovery time was varied over the range 10-80 ms. SRTs tended to be lowest (best) at the shorter recovery times but the effects were small. In the second experiment, the recovery time was varied over the range 5-320 ms. In this case, there was a clear trend for SRTs to increase with increasing recovery time. A recovery time of about 20 ms appears to be optimal.
本文描述了一系列评估和优化一款包含两种自动增益控制（AGC）形式的助听器的实验中的两个。第一种形式是前端AGC，其通常作用缓慢，可补偿不同情境下语音总体水平的变化。第二种AGC形式紧随前端AGC。信号被分成两个频段，快速作用的AGC仅应用于高频段。然后将频段重新组合。这里描述的两个实验旨在确定高频通道中AGC恢复时间的最佳值。对于轻度至中度感音神经性听力损失的受试者，在存在言语噪声的情况下，测量语音接收阈值（SRT）作为恢复时间的函数。在第一个实验中，恢复时间在10 - 80毫秒范围内变化。在较短的恢复时间下，SRT往往最低（最佳），但效果较小。在第二个实验中，恢复时间在5 - 320毫秒范围内变化。在这种情况下，SRT有明显随恢复时间增加而升高的趋势。约20毫秒的恢复时间似乎是最佳的。
