Intermediate complexity adaptive filters in acoustic echo cancellation

The authors report on recent research into the use of so-called fast Newton transversal filters (FNTF) for acoustic echo cancellation. FNTFs are fast transversal filters (FTF) with reduced order predictors. By varying the order of the predictor part, adaptive algorithms extending from low complexity/slowly converging NLMS to high complexity/rapidly converging FTF algorithms are possible. This class of adaptive algorithms thus allows a tradeoff to be made between complexity and speed of convergence