Adaptive Online Frequency Estimation of Sinusoid with Unknown Frequency

In this short paper the problem of continuous time online estimation of frequency of a mixture of sinusoidal signal is considered. A simple estimator based on minimization of a Lyapunov function is suggested for the solution of this problem. For given a sinusoid signal consisting of many frequencies, the results show that estimator is globally convergent which can be applied for any initial condition and frequency values.