Bias free adaptive notch filter based on SSCF algorithm with decorrelation parameter

An adaptive notch filter based on a second order IIR all pass filter uses a steepest descent algorithm whose cost function is the mean square of the error signal. However, there is a problem that bias error occurs in case that a broadband signal is color. In order to reduce the bias error for a FIR filter. SSCF (square sum of correlation function) adaptive algorithm has been proposed. This algorithm takes advantages of different auto correlation function between a narrowband signal and a broadband signal. By using a delayed input signal as an input signal of a cost function. In this paper, we introduce the SSCF algorithm into an adaptive IIR filter. In addition we consider the convergence condition of the SSCF algorithm for a second order IIR filter.