Tunable non-uniform filter bank mixing cosine modulation with perceptual frequency warping by allpas

A novel nonuniform cosine modulated filter bank is presented, mixing the concepts of warped DFT (Discrete Fourier Transform) filter bank and pseudoQMF system (Quadrature Mirror Filter). Unequal bandwidths are achieved by allpass transformation of uniform polyphase system. The cosine modulation results in real valued channel signals, and hence simplified subband processing. The considered filter bank can well approximate popular psychoacoustic scales, and moreover dynamically change its frequency characteristics. Key-words: time-frequency analysis, signal representations, filter banks, multirate processing, allpass transformation, nonuniform cosine modulated filter bank, perceptual frequency warping *) This work was supported by Białystok Technical University under the grant W/WI/3/02

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