Understanding and Dealing with High Frequency Error Sources in Oscilloscope Calibration

Oscilloscope calibration has traditionally been considered part of the DC & LFAC workload. Nowadays the average scope found on a development engineer’s or test technician’s bench is a 1GHz bandwidth device, and bandwidths of several GHz are common. The processes and equipment used to calibrate these higher bandwidth scopes have also increased in frequency, taking oscilloscope calibration into the realm of RF & Microwave. Metrologists and calibration technicians increasingly have to deal with a variety of high frequency considerations such as VSWR and matching errors. Understanding how these effects influence the results and how oscilloscope calibration methods address them can simplify the task of scope calibration, reduce errors and ease the burden of uncertainty analysis.