A digital simulation of an active noise control system using the filtered-x LMS algorithm

An active noise control system has been modelled using the free space sound wave expressions and the filtered-x least mean square (LMS) algorithm. The convergence speed, stability and final mean square error of the control system are investigated on the basis of this model as functions of convergence coefficient of the algorithm, disturbances, sampling rate, filter order and the error in the identification of the secondary physical path. This simulation work may provide an understanding of the mechanisms involved in the adaptive control and a guard line for the practical DSP implementation of the filtered-x LMS algorithm for active noise control.