A Fast Estimation Method for the Phase Difference Between Two Quasi-harmonic Signals for Real-Time Systems

We propose a new method of phase difference estimation between two quasi-harmonic signals with slowly varying parameters. The proposed method does not require the solution of the overdetermined systems of equations, and it may be calculated in real time. The majority of operations for their calculation can be carried out on fixed-point numbers, and that substantially simplifies algorithm realization on signal processor or FPGA. The method accuracy is near to the Cramer-Rao lower bound within the statistical error for signals with SNR is in the range from 0 to 40 dB. The advantage of the proposed method is the possibility of signal processing with slow frequency and amplitude modulation. We compare proposed method and the method based on sine-wave-fits by numerical simulation.