Line spectrum elimination of undesired signal by IIR adaptive digital filter

The authors propose a new method of line-spectrum elimination by making use of IIR adaptive digital filter (ADF) which is constructed of parallel connected second order IIR filters. And a new algorithm to control the poles of the IIR ADF is also proposed. The new algorithm utilizes the converged values of filter coefficients representing zeros of the IIR ADF as the frequency errors of the pole. The effectiveness of the new algorithm is shown in simulation results. Since the proposed algorithm can independently control each second order filter connected in parallel, the proposed IIR ADF can eliminate multiple narrow band signals