Performance-weighted blended FxLMS for changing secondary paths

The Filtered-x LMS (FxLMS) algorithm is a linear adaptive filtering approach in active noise control that estimates the signal played from a secondary speaker to cancel the presence of a noise source in a microphone. One of the requirements for this algorithm is the filter coefficients of the secondary acoustic path between the secondary speaker and the error microphone. For scenarios where the secondary path is time-varying, we would require external information to determine the current path at each time step. If the secondary path at any time lies in a finite set of possible transfer functions, we present a performance-weighted blended FxLMS algorithm that is robust to rapid changes within the set. We compare the effects of blending paths with the online selection of a single path in the set. We also compare the blended approach with the noise injection method commonly used in online secondary-path estimation.