Reconfigurable Warped Digital Filter Architecture for Hearing Aid

Abstract

Digital filterbanks in hearing aids employ an array of filters to selectively amplify sound of different frequencies to compensate hearing loss. The use of filterbanks leads to a higher usage of silicon area as there are many filters, each generating a sub-band. Reconfigurable warped digital filter is a Variable Digital Filter (VDF) that can be reconfigured to function as a low-pass, band-pass or high-pass filter with cutoff frequencies that can be varied on-the-go. We propose a system with reconfigurable warped VDF that uses a single prototype filter for generating all the necessary sub-bands. The proposed system automates the generation of the control signals for reconfiguring the filter and pipelines the processing of each sub-band to generate the requisite magnitude response. The proposed architecture is designed to achieve good audiogram matching with minimum matching error.