A new unbiased online algorithm for equation error IIR ADF

When an infinite impulse response (IIR) adaptive digital filter (ADF) is formulated using equation error formulation that minimizes directly the mean square equation error, the estimated parameters contain a bias if there is a disturbance signal. In this paper, a new online algorithm for updating equation error IIR ADF is proposed. The proposed algorithm is independent of the white disturbance signal, and hence there is no bias in the coefficient's estimate of the ADF. We also provide the analysis and simulation results which verify this kind of performance. An application of the proposed algorithm to adaptive line enhancer (ALE) is also provided.