Analysis of the harmonics contribution on the three-point interpolated DFT frequency estimator

In this paper the contribution of harmonics on frequency estimation obtained by the classical three-point interpolated Fourier method is investigated in the case when noisy and harmonically distorted complex sinusoids are analyzed. To this aim the expressions for the frequency estimation error due to harmonics and the approximated combined variance of the frequency estimator due to both harmonics and wideband noise are derived. Using the obtained expressions the contributions of each harmonic and wideband noise on the frequency estimation error are then compared. The accuracies of the derived expressions are verified through computer simulations.