Estimation of the apparent power by products of the DFT coefficients using maximum sidelobe decay Rife-Vincent windows

The paper describes algorithms of the nonparametric power estimation by summation of the products of the amplitude discrete Fourier transform (DFT) coefficients when simultaneously of sampling is assumed. As with energy-based approach for the amplitude square estimation of the one-channel 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 Rife-Vincent windows class I, which are designed for maximization of the window spectrum side-lobes fall-off, performs minimal leakage influences in estimations with acceptable noise contributions. The main criterion, which order of window and how many points of interpolation should be used, is the systematic error behavior in dependence of the number of cycles in the measurement interval.