On the design of 2-band FIR QMF filter banks using WLS technique

In the digital filter bank context, many design methods have been proposed. Most of them are for 2-band QMF FIR filter banks. The paper considers the design of (QMF) quadrature mirror filter banks using the iterative method proposed by Chang-Kann Chen and Ju-Hong Lee (1992). Simulations show that the Chen and Lee method needs much iteration. It was examined and improved by using certain modifications based on the weighted least squares (WLS) updating scheme proposed by S. Sunder et al. (1994) to design two channel QMF filter banks. As the current weighting function is adjusted from iteration to iteration, QMF bank design with equiripple reconstruction error and stopband error can be achieved. Computer simulation shows that the proposed approach produced better results than those reported previously by author Chen and Lee. The paper concludes with design examples that illustrate the effectiveness of the approach on the efficiency and performance. Furthermore, the proposed approach requires less iterations compared with existing methods and leads to filter bank design with improved performance. The resultant filter banks are efficient in terms of computational requirements.