Phase estimation of asynchronously sampled signal using interpolated three-parameter sinewave fit technique

This paper proposes an interpolated three-parameter sinewave fit method for estimating asynchronously sampled signal phase. The proposed method provides improved phase estimation of harmonically distorted signal compared to conventional three-parameter sinewave fit method with or without truncation to the closest integer number of cycles, especially when estimating phase from small number of sampled signal cycles. It is shown that the phase estimation accuracy strongly depend on the accuracy of the frequency used in the phase calculation. Measurement results confirm the simulations.