DESIGN FOR STABLE IIR PERFECT RECONSTRUCTION FILTER BANKS USING ALLPASS FILTERS

This paper presents a new method for designing two-channel IIR linear phase filter banks that satisfy both the perfect reconstruction and st ability conditions, using allpass filters. Using the perfect reconstru ction condition for filter banks, we first offer a class of structural ly perfect reconstruction implementations. Since the proposed filter b anks must satisfy the perfect reconstruction condition even though the filter coefficients are quantized, the design problem becomes the des ign of half-band filters using a delay section and an allpass filter. Therefore, stable IIR perfect reconstruction filter banks can be easil y obtained by approximating the phase responses of just the allpass fi lters. From the viewpoint of wavelets, a new method is presented for d esigning half-band filters with arbitrary flatness based on the parall el connection between the delay section and the allpass filter. Furthe rmore, by using two different allpass filters in the filter banks, the magnitude responses of low- and high-pass filters can be designed arb itrarily. (C) 1998 Scripta Technica.