A delayless alias-free subband adaptive filter structure

Adaptive subband techniques have been developed to solve complexity and slow convergence problems of the traditional fullband high-order adaptive filters. However, the effect of aliasing associated with the multirate structure, which is a source of error in the modeling of the unknown, system, and the delay introduced in the signal path, are some of the disadvantages often encountered in most of the proposed structures. In this paper, we present two delayless maximally decimated structures where the optimal channel filters are related to the wideband system in a closed form. They make use of a special DFP analysis filter bank where the polyphase components of the prototype filter represent fractional delays such that aliasing is cancelled with no need of adaptive cross-filters