Open Access18 band ANSI S1.11 filter bank based on interpolated finite impulse response technique for hearing aids
Author(s) -
S.P. Deepu,
Kini M. Ramesh,
David S. Sumam
Publication year - 2020
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2019.1009
Subject(s) - filter bank , finite impulse response , computer science , hearing aid , filter (signal processing) , digital filter , filter design , decimation , electronic engineering , computer hardware , algorithm , electrical engineering , engineering , computer vision
A low complexity interpolated finite impulse response (IFIR) based 18 band ANSI S1.11 1/3 octave digital filter bank for hearing aid is proposed and implemented using 65 nm UMC technology in this study. ANSI S1.11 specifications for 1/3 octave Class‐2 filters are chosen as design criteria in the proposed method. The strict requirements at lower bands make the hardware implementation of ANSI S1.11 filter bank complex and difficult in a power critical application like hearing aid. In the proposed technique, the maximum margin available in the filter specifications is utilised in both upper and lower band edge specifications to reduce the filter order. IFIR technique was used to reduce the computations at lower bands which can be implemented in hardware efficiently without altering the sampling frequency of the input signal. Compared to other recent architectures, >50% reduction in total number of filter coefficients is achieved and the group delay is kept <10 ms. Hardware implementation of the algorithm was done using 65 nm standard cell libraries and tested the outputs with NAL‐NL2 gain prescriptions. The matching errors are within ± 1.5dB and the core power consumption was obtained as 0.37 mW.