Recursive least-squares algorithms with improved numerical stability and constrained least-squares algorithms for multichannel active noise control systems

1.0 Introduction This paper deals with the convergence of adaptive FIR filters used for multichannel active noise control (ANC) systems [1]. In a recent paper [2], recursive least-squares (RLS) algorithms and fast-transversal-filter (FTF) algorithms were introduced for multichannel ANC. It was reported that these algorithms can greatly improve the convergence speed of ANC systems, compared to algorithms using steepest descent algorithms or their variants, as expected. However, numerical instability of the algorithms was an issue that needed to be resolved. This paper summarizes some work that has recently been done to address this numerical instability problem. For the full detailed description of the new proposed algorithms, the reader should refer to [3].