Spectrum Analysis of Waveform Digitizers by IDFT and Leakage Minimization

The paper presents possibility of the spectrum estimation of a uniform sampled signal, which is obtained by the dynamic testing of the measurement channel of a waveform digitizer. The advantages of the weighted DFT interpolations for the frequency, amplitude, and phase estimations in order to reduce the leakage effect of the fundamental component in the investigation of the residual spectrum is described. The proposed non-parametric algorithms retain all benefits of DFT approaches and improve the estimation accuracy as a function of a number of the signal cycles in the estimation interval. The spectrum of the window used must be formally well known (like the Hanning window) for better analytical expression of the parameter estimation.