Simple design of oversampled uniform DFT filter banks with applications to subband acoustic echo cancellation

Subband adaptive "ltering, which is the basis of modern acoustic echo cancellation (AEC) systems, is an important application of "lter banks in which critical sampling cannot be used in general because of decimation aliasing e!ects. This leads to the use of oversampling schemes in the "lter bank design wherein the perfect-reconstruction (PR) or near PR property is still required. In this work, a simple design technique for uniform DFT "lter bank with near PR property is presented for the purpose of subband adaptive "ltering. The prototype "lter in the proposed "lter banks is derived simply by performing an interpolation of a two-channel QMF "lter, which can be obtained easily by computation or table look-up. An e$cient implementation of the "lter banks based on a weighted-overlap-add structure is described that allows #exibility in oversampling. The "lter bank design technique presented in this paper is of particular interest in engineering applications, as demonstrated by design examples and experimental results in a real-time subband AEC application. ( 2000 Elsevier Science B.V. All rights reserved.