Active noise control with online feedback-path modeling using adaptive notch filter

The feedback path (FBP) compensation has been a research topic in the field of active noise control (ANC) for decades and a number of offline and online FBP modeling techniques have been proposed in the literature. In this paper, a novel ANC system equipped with an online FBP modeling (FBPM) and neutralization (FBPMN) subsystem is proposed. The new system consists of three adaptive subsystems, namely 1) ANC controller with only two weights for each frequency target, 2) second-order adaptive IIR notch filter, and 3) an FBPMN filter. It yields very promising performance for narrowband noise signals generated by rotating machines such as fans, motors, large-scale strandcutters, etc. An auxiliary white Gaussian noise is injected into the ANC system to implement the FBPMN, which is scaled by a function of the residual noise to reduce its contribution to the residual noise power. Extensive simulations with synthetic/real secondary paths reveal that the proposed ANC scheme ensures excellent noise reduction performance as well as practically attractive computational efficiency.