Increasing the Robustness of a Preconditioned Filtered-X

Abstract—This letter presents a robustification of the precon-ditioned Filtered-X LMS algorithm proposed by Elliott et al.. The method optimizes the average performance for probabilistic un-certainty in the secondary path and relaxes the SPR condition for global convergence. It also prevents large amplification in the pre-conditioning filters due to secondary path zeros on and/or close to the unit circle, which may yield overactuation in practical applica-tions. Index Terms—Acoustic noise, adaptive control, adaptive signal processing, feedforward systems, robust filtering. I