Analysis of Various Methods of Measuring the Voltage Division Factor of a Voltage Probe

Voltage probes are used to measure powerline conducted emissions from equipment under test (EUT) for in-situ tests and/or when the mains voltage and/or current required by the EUT exceeds the rating(s) of a readily available line impedance stabilization network (LISN). In a separate three-part series of articles, we presented an S-parameter-based method of measuring the voltage division factor (VDF) of LISNs as an alternative to the method using a three-port coaxial T-connector and comprehensively analyzed and compared both methods. Upon discovering the significant advantages of the S-parameter method for LISNs, we decided to explore the application of these procedures to voltage probes. Regarding voltage probes, we find ambiguities in the measurement procedures specified by the applicable standards, that the output mismatch error contribution with the T-connector method sheds light on these ambiguities, and that the S-parameter method can remove the ambiguities. Hence, the S-parameter method is superior regarding accuracy and measurement uncertainty for voltage probes as well as LISNs.