Method for real-time estimation of phase-shift angle and instantaneous frequency of quasi-harmonic signals

In this paper, a method for estimating the phase shift angle between two quasi-harmonic signals over a small observation interval is proposed and investigated. The developed method allows us to study the dynamics of phase angle and instantaneous frequency in real time. Conditions under which the phase angle estimation is stable in the presence of amplitude and frequency modulation are formulated. Analytical expressions for estimation errors depending on signal parameters and normal noise level are obtained. The proposed method involves a small number of computing operations and can be used in autonomous systems, where computational resources are usually limited.