Online secondary path estimation in active noise control systems using a scheduled step size algorithm

Abstract

In an active noise control (ANC) system, a fast and robust estimation of secondary path filter is important for reducing a primary noise effectively. A destructive interference signal of the noise generated by the actuator can effectively remove the primary noise at the target point when the secondary path filter is estimated quickly and precisely. In this paper, a scheduled-step size NLMS (SS-NLMS) algorithm is applied to estimate the secondary path filter in the ANC system. Analyzing the curve of mean square deviation (MSD) geometrically, it is divided into a transient stage and a steady state stage. In a specific value of a step size, the value of MSD is decreased in the transient stage and is kept in the steady state stage. Using the analysis, the step size in the interval (0,1) was scheduled in each iteration for fast convergence speed and low steady state error. An advantage of the proposed system is not required to additional computations for fast and robust estimation of the secondary path filter. In the ANC system, the SS-NLMS algorithm is an innovative algorithm which has not existed. Show more