| 摘要 |
Change over of the sound receiving characteristic of a hearing aid having spaced apart first and second microphone means (Fmic, Bmic) between the omnidirectional characteristic and a directional characteristic is effected by controlled attenuation and time or phase delay of signals derived from the signals (Xfront, Xback) from the first and second microphone means before forming and overall combined signal (Y) to be supplied to the hearing aid signal processor, whereby the overall combined signal (Y) is determined by Y = Xfront * (1 - <i>omni</i> * e<-j omega T>) + Xback * (omni - e<-j omega T>), where <i>omni</i> is an adjustable attenuation control parameter preferably in the range 0 </= <i>omni</i> </= 1 and T is a time delay corresponding to the acoustical delay between the first and second microphone means. In result, the change between the omnidirectional characteristic and any desired form of the directional characteristic is effected as a smooth change-over substantially without affecting phase relationship, time delay and amplitude characteristic of the hearing aid. |
