A DESIGN OF NONUNIFORM COSINE-MODULATED FILTER BANKS

A design method of nonuniform CMF banks ris presented which is derived in association with a uniform CMF bank, In this derived nonuniform CM F bank, each constituent nonuniform filter is formed by merging the re levant uniform filters in the associated uniform CMF bank, The validit y of the derived design is investigated in terms of the band selectivi ty of the nonuniform filters, the alias cancellation among the nonunif orm analysis and synthesis filters, and the distortion function of the overall filter bank, The investigations are done in a rigorous manner via three proved properties, which provide the criterion that the pro posed design method is applicable if, and only if, the upper band edge frequency of each nonuniform filter is an integral multiple of the ba ndwidth of the corresponding band, Design and implementation aspects a re considered for the proposed nonuniform CMF bank, which reveals that the design procedure and the structure of the uniform CMF bank are mo stly preserved in the nonuniform implementation.