FPGA-based implementation of comb filters using sequential multiply-accumulate operations for use in binaural hearing aids

Abstract

Sensorineural hearing loss, caused by damage to the cochlea in the inner ear or to the auditory nerve, is associated with reduced dynamic range and increased spectral and temporal masking and results in degraded speech perception. For listeners using binaural hearing aids, spectral splitting of the speech signal can be used to reduce the effects of increased intraspeech spectral masking thereby improving speech perception. It has been reported that a pair of linear-phase comb filters, with auditory critical bandwidth based complementary magnitude responses selected for perceptual balance of loudness, resulted in a significant improvement in speech perception without affecting localization of broadband sound sources. The paper presents an investigation for FPGA-based implementation of these comb filters for use in binaural hearing aids. It is shown that a processing architecture employing sequential multiply-accumulate operations results in an efficient implementation.