Apparent Power Estimation by Interpolation of the Product of the Dft Coefficients

This paper describes the possibility of estimating the apparent power of a signal component using the interpolation of the products of amplitude discrete Fourier transform (DFT) coefficients. As with energy-based approach for the amplitude square estimation of the onechannel signal, the apparent power in the two-channel case can be estimated with the multiplied amplitude DFT coefficients around the component peak and a suitable interpolation algorithm. The use of the Hann window with well known frequency spectrum and the largest local amplitude DFT coefficients give lower systematic errors than the energy-based approach, although the frequency has to be estimated first.