Recursive least squares generalized FIR filter estimation for active noise cancellation

A feedforward control algorithm for active noise control based on the recursive estimation of a generalized finite impulse response (FIR) filter is presented in this paper. Recursive least square estimation (RLSE) with variable forgetting factors is applied to a commercial air ventilation silencer to provide the online estimation of the generalized finite impulse response (FIR) filter to obtain active noise compensation in an airduct. The advantage of the generalized FIR filters lies in the possibility to include prior knowledge of system dynamics in the tapped delay line of the filter. It is shown that a significant improvement in noise cancellation is obtained with the implementation of generalized FIR filter for feedforward ANC.