Title :
Cochlear filters design using a parallel dilating-biquads switched-capacitor filter bank
Author :
Lin, Jyhfong ; Ki, Wing-Hung ; Thompson, K. ; Shamma, Shihab
Author_Institution :
Maryland Univ., College Park, MD, USA
Abstract :
A parallel filter bank is proposed to implement cochlear filters using very-large-time-constant switched-capacitor (SC) biquads. Significant hardware reduction is achieved in three ways. First, the number of biquads is reduced by biquad-sharing such that each channel consists of three biquads in parallel, and a n-channel filter bank requires only n+2 biquads and n sum-gain amplifiers for implementation. Secondly, area-efficient SC biquads are used, and the capacitor spread of each biquad is approximately 1/√Ω0T, where Ω0 is the pole frequency and T is the sampling period. Finally, a lowpass notch biquad is used to avoid a zero at z=-1, which results in a very small capacitor in each biquad. Simulation results for a 32-channel filter bank are given to demonstrate the validity of this design
Keywords :
active filters; speech analysis and processing; switched capacitor filters; area-efficient SC biquads; biquad-sharing; capacitor spread; cochlear filters; hardware reduction; lowpass notch biquad; parallel dilating-biquads switched-capacitor filter bank; pole frequency; sampling period; sum-gain amplifiers; Band pass filters; Capacitors; Channel bank filters; Educational institutions; Filter bank; Filtering theory; Frequency; Hardware; Sampling methods; Transfer functions;
Conference_Titel :
Circuits and Systems, 1992. ISCAS '92. Proceedings., 1992 IEEE International Symposium on
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-0593-0
DOI :
10.1109/ISCAS.1992.230371
