Measurements of transient phenomena with digital oscilloscopes

While the dynamic accuracy of an oscilloscope is usually defined in terms of its bandwidth, actually it also depends on the measured signal properties, and, for digital oscilloscopes, also on ADC performances. In this paper, the effects of sampling upon rise time measurements with a digital oscilloscope are considered. The effects of sampling are analyzed and modeled for various input step signals. In particular, a simple expression is derived, which conveniently models the sampling contribution to the overall rise time measurement error. Using these results, a correction technique is proposed to remove the interpolation error bias, and its applicability is discussed also with respect to analog error sources.