Design of digital allpass‐based two‐channel quincunx QMF banks
Ju-Hong Lee, Yi‐Lin Shieh · International Journal of Circuit Theory and Applications · 2012
ABSTRACT This paper presents a novel structure for constructing two‐channel quincunx quadrature mirror filter (QQMF) banks. The analysis and synthesis filters of the QQMF bank are composed of two‐dimensional (2‐D) recursive digital allpass filters with symmetric half‐plane support regions. Using the 2‐D doubly complementary half‐band property possessed by the analysis and synthesis filters, we facilitate the design of the digital allpass‐based two‐channel QQMF banks. For finding the coefficients of the 2‐D recursive symmetric half‐plane digital allpass filters, the design problem is appropriately formulated to result in an optimization problem that can be solved by using a weighted least‐squares algorithm in the minimax (L∞) optimal sense. The novelty of the proposed design method is that the designed 2‐D QQMF bank achieves perfect magnitude response and possesses satisfactory phase response without requiring extra phase equalizer. Simulation results are also provided for illustration and comparison. Copyright © 2012 John Wiley & Sons, Ltd.