Dynamic behavior of a digital phase estimator

A frequency-domain estimator for the phase of a sinewave with respect to an arbitrary time reference is presented. The behavior of the estimate is analyzed when the unknown phase is a time-varying function. No information on the signal frequency is required, and highly accurate results are provided even when the signal is distorted by other spectral components (harmonics or spurious tones). The effect on the estimate of an instantaneous phase with a step, linear or sinusoidal time behavior is reported, and the influence of small phase fluctuations and of spurious signal disturbances is taken into account.<<ETX>>