A class of biorthogonal nonuniform cosine-modulated filter banks with lower system delay

In this paper, the theory and design of a class of perfectreconstruction (PR) biorthogonal nonuniform cosine-modulated filter banks (CMFB) is proposed. It is based on a recombination or merging structure previously proposed by the authors [ 13. By relaxing the original CMFB and the recombination transmultiplexer (TMUX) to be biorthogonal. nonuniform CMFBs with lower system delay can be obtained. This increases the possible choices of the prototype filters and greatly reduces the overall system delay of the nonuniform filter bank. A new method is also introduced to suppress the spurious response resulting from the mismatch in the transition bands of the two biorthogonal CMFBs. Design example shows that nonuniform CMFBs with good stopband attenuation, lower system delay and implementation complexity can be realized using the proposed method.