HEARING-AID MEASUREMENTS WITH SPEECH AND NOISE SIGNALS

An increasing number of hearing aid types include one or more features which are intentionally non-linear. In such devices measurement of fr equency response and distortion using sweep tone measurements are typi cally of little relevance. Five different non-linear hearing aid types were used to evaluate three different broad-band measuring methods. T he results revealed that these methods were meaningful in estimating a verage frequency response obtained with a specific input signal, but n one of the three methods used in the study was able to evaluate separa tely the effects of the most important signal modifications: memoryles s non-linearity like peak clipping, time-varying gain from AGC and add itive internal noise.