Distortion Analysis of Analog-to-Digital Converter by IDFT and Least-Squares fitting algorithm

This paper compares two basic procedures used in estimations of the significant components in the residual spectrum in the ADC dynamic testing. The properties 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 nonparametric interpolation 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 comparison of the three-point estimation algorithms to the least-squares four-parameter sine-fit estimation described in the IEEE standard 1241 shows the estimation effectiveness.