Design of quadrature mirror-image filter banks for low-power applications

A method for the design of quadrature mirror-image filter QMF banks for low-power applications based on the algorithm of Chen and Lee (1992) is proposed. The method entails designing a sequence of cascaded filter sections such that any number of consecutive sections starting with the first one constitute an optimal design for a given set of specifications for the filter bank. The method includes modifications that allow for the increase in vanishing moments with the increase in the number of filter sections and it can incorporate techniques that facilitate control over the stopband attenuation or enable the design of low-reconstruction delay QMF banks. Using a simple adaptive mechanism, the input and output signals are used to determine the minimum number of sections that should be used in order to provide a desired performance. By turning off unrequired sections, power and computational complexity can be minimized