Multichannel IIR filter banks composed of all‐pass filters as construction elements

Abstract

AbstractFilter banks are being used in many areas, e.g., voice processing in communication systems; and active research has been on‐going in this field in recent years.This paper describes a method of realizing multichannel IIR filter banks which could divide the frequency range into an arbitrary number of uniform bands. In this method, filter banks are formed by shifting the low‐pass characteristics with the help of variable transformation with respect to ω and a π/2 phase shifting with the help of a Hilbert transformer. Hence, this design procedure becomes similar to the design of linear‐phase all‐pass filters.This IIR filter including the Hilbert transformer can be implemented with the help of an all‐pass filter, and thus low coefficient sensitivity property can be realized. Moreover, the transition band is narrower compared to the FIR structure. Other than the forementioned merits, the design is comparatively simple; and all the coefficients can be obtained in an analytical way using Fourier series expansion.