A Novel RNS Hardware Architecture of FRM Filter Banks for Digital Hearing Aids

This paper presents a novel hardware architecture for Frequency Response Masking (FRM) Filter Bank based on Residue Number System (RNS) arithmetic for Digital Hearing Aids (DHA). FRM is a computationally efficient approach for filter bank design that separates different frequencies based on the Audiograms of a patient. However, filter banks are critical power-hungry elements that require high computational resources. Therefore, the proposed architecture aims to provide an efficient implementation of FRM filter banks, which can improve the value and affordability of DHAs. The proposed architecture employs FIR filters in direct form, linear phase, and poly phase using RNS arithmetic. This approach enables the performance of arithmetic operations in parallel and independently. The concepts are further extended for the efficient implementation of FRM filter bank. The results of the proposed architecture show that direct implementation reduces the delay when the number of taps increases in the FIR filter. However, to reduce computational resources and optimize the area requirement, a Folded RNS architecture is also proposed. The Folded RNS architecture offers hardware savings of 23–27% for a 40-tap FIR filter and 29–31% for a 60-tap FIR filter. Additionally, it improves speed by 13–15% for a 40-tap FIR filter and 16–19% for a 60-tap folded RNS FIR filter. The implementation of FRM filter bank using the folded FIR filter shows the same trend in hardware saving and speed improvement as in the case of FIR filters. These results demonstrate that the proposed hardware architecture has the potential to improve the efficiency and affordability of DHAs while enhancing the listening comfort, which can enhance the quality of life for patients with hearing impairments.