A new critically sampled non-uniform subband adaptive structure

In this paper, a non-uniform subband adaptive structure with critical sampling of the subband signals is derived. With the assumption of non-overlapping between non-adjacent analysis filters, the resulting structure yields exact modeling of an arbitrary FIR system. An LMS-type adaptation algorithm, which minimizes the sum of the subband squared-errors, is obtained for updating the coefficients of the proposed structure, resulting in significant convergence rate improvement for colored input signals when compared to the fullband LMS algorithm. Computer simulations illustrate the convergence behavior of the proposed non-uniform subband adaptive filter in the applications of system identification and acoustic echo cancellation.