Least-squares estimation of time-base distortion of sampling oscilloscopes

We present an efficient least-squares algorithm for estimating the time-base distortion of sampling oscilloscopes. The method requires measurements of signals at multiple phases and frequencies. The method can accurately estimate the order of the harmonic model that is used to account for the amplitude nonlinearity of the sampling channel. We study several practical problems related to the time-base distortion estimation, such as the effect of averaging and sample size requirements. We also compare the relative performance of various methods for estimating time-base distortion using simulated and measured data.