The Method of Adapting Directional Microphone Function to Hearing Aids

• Main Authors: Chen-Yun Hong, 洪晨耘
• Other Authors: Shuenn-Tsong Young
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/avhpxj

碩士 === 國立陽明大學 === 醫學工程研究所 === 97 === Hearing aids commonly with built in noise cancellation technologies, one of them is directional microphone, which the main purpose is to emphasize the speech signal in front and reduce the noise signal in the back. In this study, there are two purposes, firstly, to develop the adaptive directional microphone function algorithm in hearing aids let the hearing aid users who are in complex sound environment can auto-reduce the noise signal effectively, meanwhile detect the moving source of noise and decrease it. Secondly, developing the algorithm of noise / speech detector system to detect whether the speech signal existed or not in the environment, in order to adjust the on and off control of directional microphone in different sound environment. We burn these two algorithm in the signal processing chip of GA-3280, and fabricate varied elements to complete a hearing aid with adaptive directional microphone function. According to the effectiveness of our directional microphone, the ideal result of ANSI would increase 5~20 dB SPL of signal to noise ratio in each band. In real ear measurement, would increase 4~13 dB SPL of S/N ratio, and in noise / speech detector system measurement, would be above 80% speech identification in different kind of sound environment.