Accuracy of the sine-wave normalized frequency estimation by interpolated DFT method with rectangular window

The paper analyzes the accuracy of the normalized frequency estimator of a sine-wave provided by the interpolated discrete Fourier transform (IpDFT) method based on the rectangular window. The expression for the maximum of the magnitude of the estimation error due to the spectral interference from the image component is derived. The obtained expression is validated by means of computer simulations. Moreover, the influence of the spectral interference on the normalized frequency estimator is compared with the effect of wide-band noise superimposed to the sine-wave. From this comparison it follows that the accuracy of the normalized frequency estimator is mostly affected by spectral interference. Finally, this conclusion is validated by both computer simulations and experimental results.