An Improved Approach for the Design of Two-Channel Quadrature Mirror Filter Bank Using Unconstrained Optimization.

In this paper, an improved method for the design of two-channel Quadrature Mirror Filter (QMF) bank with linear phase characteristics is presented. A prototype low-pass filter of the QMF bank is implemented using polyphase components. The design technique optimizes the value of the prototype filter coefficients to match the ideal transfer function of the filter bank using Eigenvalue-Eigenvector approach without any matrix inversion. The optimization is carried out to minimize an objective function which is a linear combination of pass-band error and stop-band residual energy of the low-pass analysis filter of the filter bank, and square error of the distortion transfer function of the QMF bank at the quadrature frequency. The simulation results show that the proposed method requires less computational time and number of iterations with similar performance of Peak Reconstruction Error (PRE) in comparison to already existing methods. [ABSTRACT FROM AUTHOR]