Stability and Bias Analysis for Adaptive Normal State-Space Notch Digital Filters

This paper deals with an adaptive notch digital filter that employs the normal state-space realization of a single frequency second-order IIR notch digital filter. A simplified gradient-descent method is applied to minimize the mean-squared output error of the filter iteratively. The stability and frequency-estimation bias of the adaptive normal state-space notch digital filter are then analyzed. A numerical example is presented to demonstrate the validity and effectiveness of frequency-estimation bias of the adaptive normal state-space notch digital filter.