Multi-channel active noise control for periodic disturbances

The paper presents a multichannel active noise control algorithm that is designed to reject periodic noise signals of unknown frequency. The algorithm is the extension of a previously-proposed disturbance rejection algorithm in which the frequency of the disturbance is estimated through an adaptive notch filter and the estimate is used in a feedforward disturbance rejection scheme. Improvements over the earlier approach include a better frequency estimation scheme and an extension to multichannel systems. Experimental results on an active noise control testbed demonstrate the validity of the analytical results and the success of the method in a practical environment.