Complex adaptive notch filter for detection of real sinusoid

This paper presents a new realization of adaptive notch filter based on a cascade of complex first-order notch filters. Unbiased frequency estimation of a real sinusoid has been achieved by thinning the notch bandwidth. It has been shown that the simple closed form of mean square error (MSE) for frequency estimation is given by using the results for first-order complex notch filter and its robustness to the frequency of input sinusoid has been shown. Computer simulation results are presented to validate the analysis.