A method for online secondary path modeling in active noise control systems

The paper proposes a new method for online secondary path modeling in active noise control (ANC) systems. The proposed method is a modified version of the basic method, proposed by L.J. Eriksson and M.C. Allie (1989). The objective is to realize improved performance at a reasonable computational cost. The control filter is adapted by using the same error signal as used in the adaptation of the modeling filter. Furthermore, a variable step size (VSS) LMS algorithm is used to adapt the modeling filter. The basic idea of VSS stems from the fact that the disturbance signal in the desired response of the modeling filter is decreasing in nature, (ideally) converging to zero. Hence, a small step size is used initially and later its value is increased accordingly. The computational complexity of the proposed method is comparable to the Eriksson and Allie method, and it gives the best performance among existing methods. Computer simulations are presented to show the effectiveness of the proposed method.