Pipelined adaptive IIR filter architectures using scattered and relaxed look-ahead transformations

Fine-grain pipelined architectures for adaptive infinite impulse response (AIIR) filters are presented in this paper. The AIIR filters are equation error based. The proposed architectures are developed by employing a combination of scattered look-ahead and relaxed look-ahead pipelining techniques. First, a pipelined system identification scenario is developed. Then, the scattered look-ahead technique is applied to the nonadaptive (but time-varying) recursive section. Finally, a relaxed look-ahead technique is applied to the adaptive blocks. Convergence analysis of the pipelined architectures is presented and verified via simulations. It is shown that speedups of up to 8 and more can be achieved with marginal or no degradation in performance.