Reconfigurable digital FIR filter bank for hearing aids using minimax algorithm

In this paper, a reconfigurable filter bank for digital hearing aid in Canonical Sign Digit Space is proposed to reduce the complexity while implementing hardware. The major requirement of hearing aid is that it should be able to provide different sound decomposition schemes in-order to cope with the needs of different patients. In this paper, the filter bank is based on fractional interpolation which enables the realization of the entire system with two different prototype filters, thus reducing the system complexity. A 4-bit control signal is used to alter the subband schemes without modifying the configuration of the filter bank. The gain of each subband is then optimized using Minimax algorithm. The proposed filter bank can achieve satisfactory performance in audiogram matching which is shown by means of examples.