Interpolation in the frequency domain to improve phase measurement

Possibilities of an error reduction of the phase estimation with an interpolated discrete Fourier transform (DFT) for the rectangular window are described. The improvement of the phase estimation from the rough measurement results is achieved with considering the long leakage effects of the window spectrum weighted by the signal components. Properties of interpolations are studied with respect to their ability for correction the systematic effect in a trade of increasing the estimation uncertainty. Uncertainties of the one-point and the two-point phase estimations have been studied. The simulation and experimental results are presented showing the effectiveness of the component phase estimation.