Adaptive Feedback Active Noise Control (AFBANC) System Equipped with Online Adaptation and Convergence Monitoring of the CancellationPath Estimation (CPE) Filter This papers aims to develop an Adaptive Feedback Active Noise Control (AFBANC) system comprising two adaptive filters. The first adaptive filter is the same as found in the traditional AFBANC systems and is adapted using the classical Filteredx Least Mean Square (FxLMS) algorithm. The stability of the FxLMS algorithm requires filtering the reference signal via a xe2x80x98goodxe2x80x99 estimate of the cancellation path (CP) present between the cancellation loudspeaker and the error microphone. Since the CP may be timevarying in the practical situations, the task of the second adaptive filter is to provide estimation of the CP during operation of the AFBANC system. The CancellationPath Estimation (CPE) filter is excited by a probe signal and is adapted using a delaybased Normalized Least Mean Square (NLMS) algorithm. The proposed system is equipped with a simple strategy to monitor the convergence status of the CPE filter. The developed strategy allows to inject a large (small) probe signal during the transient (steady) state of the AFBANC system. Computer simulation are carried out which demonstrate the effective performance of the developed system.

A robust online secondarypath filter active noise control system for noisy inputs and impulsive noises in sparse systems A robust online secondarypath filter active noise control (ANC) system for noisy inputs and impulsive noises is proposed in sparse systems. The three methods are applied to the online secondary path ANC system. First, xe2x84x92 0 norm cost of control filter is added to the cost function to be a fast convergence rate in the sparse systems. Second, bias compensating term is also applied to the update equation of the control filter for robustness to noisy inputs. Last, threshold parameter is applied to prevent wrong updates from the impulsive noises. The simulation results show that the proposed online secondarypath filter ANC system with the three methods not only has a fast convergence rate and low steady state error but also has robustness for the noisy inputs and impulsive noise in sparse systems compared to other ANC systems.