Speech enhancement system for hearing aid - uses filters for adjusting speech signal spectral envelope by amplifying signal peaks

摘要

The speech enhancement system improves the comprehension of speech signals, by altering their spectral envelope, so that the amplitudes of the speech wave peaks are amplified and the depths of the troughs between these peaks are increased. The formation and alteration of the speech signal spectral envelope is effected with a min. delay, pref. using adaptive grid filters (9,10,11). The first of these filters (9) is supplied with a set of filter coefficients via an iterative process, with adaptive correction w.r.t. the variation in the speech signals. The remaining filters (10,11) are supplied with filter coefficients which are adjusted in accordance with the first filter. ADVANTAGE - Highly miniaturised, low current consumption and no discernible time delay during envelope adjustments.