Estimation of the squared amplitude in the frequency domain

The paper presents and compares the possibilities to estimate the square of the amplitude for better estimation of the signal component power. It has been pointed out the advantage of the weighted DFT interpolations for the amplitude square estimation. Using the Hann window, for which the frequency spectrum is well known, and the three largest local amplitude DFT coefficients gives lower systematical errors in squared interpolated approach or in interpolated squared approach than the energy based approach although the frequency has to be estimated in the first step.