TY - JOUR
T1 - 11.25-ms-group-delay and low-complexity algorithm design of 18-band quasi-ANSI S1.11 1/3 octave digital filterbank for hearing aids
AU - Lai, Shin Chi
AU - Liu, Chih Hao
AU - Wang, Ling Yi
AU - Chen, Shin Hao
AU - Chen, Ke-Horng
PY - 2015/6/1
Y1 - 2015/6/1
N2 - This paper presents a novel algorithm and architecture design for 18-band quasi-class-2 ANSI S1.11 1/3 octave filterbank. The proposed design has several advantages such as lower group delay, lower computational complexity, and lower matching error. The technique we developed in this paper can be summarized as follows: 1) a simple low-pass filter (LPF) and discrete cosine transform (DCT) modulation are utilized to generate a uniform 9-band filterbank first, and then all elements of ${\rm z}-1 are replaced by all-pass filters to obtain a non-uniform filterbank; 2) a fast recursive structure and variable-length algorithm is further developed to efficiently accomplish DCT modulation. Thus, the spectrum of LPF can be easily spanned and flexibly extended to the location of the desired central frequency; 3) after employing the multi-rate algorithm, an 18-band non-uniform filterbank is generated from two 9-band sub filterbanks by following the proposed design steps and parameter determinations. Compared with the latest Liu 's quasi-class-2 ANSI S1.11 design, the proposed method-I (Proposed-I) totally has 72.8% reduction for multiplications per sample, 11.25-ms group delay, and 59 additions decreased per sample. Moreover, the maximum matching error of the proposed method-II (Proposed-II) is averagely equal to 1.79 dB much smaller than that of the latest Wei 's design. For the proposed variable-length DCT modulation, only 2 adders, 2 multipliers, 2 multiplexers, and 5 registers are required for hardware implementation after applying VLSI retiming scheme. Overall, the proposed filterbank design would be a new solution for future applications in the area of hearing aids.
AB - This paper presents a novel algorithm and architecture design for 18-band quasi-class-2 ANSI S1.11 1/3 octave filterbank. The proposed design has several advantages such as lower group delay, lower computational complexity, and lower matching error. The technique we developed in this paper can be summarized as follows: 1) a simple low-pass filter (LPF) and discrete cosine transform (DCT) modulation are utilized to generate a uniform 9-band filterbank first, and then all elements of ${\rm z}-1 are replaced by all-pass filters to obtain a non-uniform filterbank; 2) a fast recursive structure and variable-length algorithm is further developed to efficiently accomplish DCT modulation. Thus, the spectrum of LPF can be easily spanned and flexibly extended to the location of the desired central frequency; 3) after employing the multi-rate algorithm, an 18-band non-uniform filterbank is generated from two 9-band sub filterbanks by following the proposed design steps and parameter determinations. Compared with the latest Liu 's quasi-class-2 ANSI S1.11 design, the proposed method-I (Proposed-I) totally has 72.8% reduction for multiplications per sample, 11.25-ms group delay, and 59 additions decreased per sample. Moreover, the maximum matching error of the proposed method-II (Proposed-II) is averagely equal to 1.79 dB much smaller than that of the latest Wei 's design. For the proposed variable-length DCT modulation, only 2 adders, 2 multipliers, 2 multiplexers, and 5 registers are required for hardware implementation after applying VLSI retiming scheme. Overall, the proposed filterbank design would be a new solution for future applications in the area of hearing aids.
KW - ANSI S1.11
KW - digital hearing aids
KW - discrete cosine transform (DCT) modulation
KW - filterbank
UR - http://www.scopus.com/inward/record.url?scp=85027934893&partnerID=8YFLogxK
U2 - 10.1109/TCSI.2015.2411795
DO - 10.1109/TCSI.2015.2411795
M3 - Article
AN - SCOPUS:85027934893
VL - 62
SP - 1572
EP - 1581
JO - IEEE Transactions on Circuits and Systems I: Regular Papers
JF - IEEE Transactions on Circuits and Systems I: Regular Papers
SN - 1549-8328
IS - 6
M1 - 7083730
ER -