A Modified Structure for Feed forward Active Noise Control Systems with Improved Performance

Several approaches have been introduced in literature for active noise control (ANC) systems. Since FxLMS algorithm appears to be the best choice as a controller filter, researchers tend to improve performance of ANC systems by enhancing and modifying this algorithm. In this paper, the existing FxLMS algorithm is modified which provides a new structure for improving the noise reduction and convergence rate. Here the proposed method uses two variable step sizes, one for control filter and another for modelling filter. The control filter step size is varied based on the secondary path threshold signal ˆδ_λ. The modelling filter step size is varied based on error signal f (n) . It is shown that in the proposed method ANC system noise reduction rate and convergence rate are improved dynamically than the FxLMS variable step size methods. The computer simulations results indicate effectiveness of the proposed method.