Research on Fractional Delay Filter and Mismatch Feature Based on Least Mean Square Rule for CI Device

Cochlear implant was traditionally equipped with one omni-microphone, and directional microphone has been applied in present papers and products. Microphone array based methods use space information to differentiate the desired signal and ambient noise. Delay value is an important parameter in beamforming, which determine the beam pattern. In the application of cochlear implant front-end signal acquisition, we need to solve the fractional delay problem as small distance between microphones. The proposed least mean square error rule can minimize the average error for the whole frequency band. And the fractional delay filter characteristic and mismatch are analyzed to help to further algorithm application in front-end beamforming for cochlear implant.