A new method is presented to determine the time-base errors of sampling instruments. The method does not require a model for the time-base error and, thus, provides accurate estimates where model-based methods fail. Measurements of sinewaves at multiple phases and frequencies are used as test signals. A harmonic model is used to account for nonlinearity of the sampling channel and use of an independent method for estimating the channel noise and jitter allows an accurate estimate of the harmonic order. Methods are presented for separating the harmonics generated by the sampling channel from those generated by the time-base distortion. The use of an iterative sine fit rocedure gives accurate results in a short time. A new weighting procedure is described which minimizes the error in the estimates. Guidelines are given for selecting good sets of test frequencies. Results are shown for both simulated and real data.
Citation: IEEE Transactions on Instrumentation and Measurement
Pub Type: Journals
digitizer, distortion, iterative, simulation, sinefit, timebase, weighting