An Efficient Least-Squares Design of Two-Channel Quadrature Mirror Filters Using IIR All-Pass Filters

The design of two-channel quadrature mirror filter banks can be constructed by using IIR all-pass filter in the least-squares sense without causing magnitude distortions. The complex nonlinear phase optimization problem is first converted into solve a system of linear equations. Then, the associated matrices involved in the set of linear equations can be further formulated as a Toeplitz-plus-Hankel form such that a matrix inversion is avoided. Simulation results confirm that the proposed method achieves good performance as well as with effectiveness.