DESIGN AND IMPLEMENTATION OF QUADRATURE MIRROR FILTER

Abstract

Quadrature mirror filter is aliasing cancellation filter banks. In general, analysis/reconstruction filter banks introduce, to some degree, aliasing, amplitude distortion and phase distortion to the reconstructed signal. The performance of subband coders relies on the ability of analysis and reconstruction filter banks to provide good isolation between contiguous frequency bands of speech signals. These impairments as well as the overall system delay and implementation complexity are the major issues in the design of filter banks for sub band coding systems. This presents a detailed study of the Quadrature mirror filter banks that deal with the above issues. It includes ideal quadrature mirror filter design using different window techniques and their results. The further study also includes QMF filter banks design using optimization. We have used a practical approach to design QMF filter banks. We have also designed exact reconstruction QMF filter banks using Remez algorithm and using built in function in Matlab and calculated reconstruction error. We have compared the reconstruction error in all above methods.