Novel approach to the design of weighted minimax quadrature mirror filters

The weighted least squares (WLS) algorithm is widely employed for designing quadrature mirror filters (QMF) in the frequency domain. The equiripple nature of the WLS design and its performance near the filter band edge have been reported to be better than that of the least squares (LS) design. It is known that these design techniques suffer from pass-band anomaly under different stop band frequencies. We have proposed an algorithm to eliminate pass-band anomaly of LS design. In this paper, we show that WLS can be modified in way similar to that proposed for the LS design. The characteristics of the resulting filters satisfy the stop band requirements and do not show anomaly in the pass band region.