Frequency estimation by adaptive notch-filtering in cascade/parallel form

A novel algorithm is presented for frequency estimation of sinusoids in noise. A priori knowledge of relations between the sinusoid frequencies (e.g. harmonics) is incorporated into the procedure, resulting in a single parameter estimation. The special ARMA system used-the notch filter-is implemented in cascade/parallel form with independent second-order sections. The update for each section is done by the recursive prediction error method. Simulation results are presented and compared to results obtained with the direct-form implementation of adaptive notch filters