Quantifying the maximum phase-distortion error introduced by signal samplers

Quantifying the errors introduced by signal sampler imperfections is of interest to people who are doing frequency domain measurements. The phase-distortion introduced by the sampler is hard to quantify and is usually neglected. In this article, upper bounds for this phase-distortion error are derived which are based upon simple assumptions, namely that the sampler weighting function is strictly positive, that it is limited in time, and that the function has only one local maximum. The theoretical limits are applied in order to specify the accuracy of a calibration procedure for broadband sampling oscilloscopes.