Selected Aspects of Traceability and Uncertainty of Frequency Measurements with Counters

SummaryFrequency counters are widely used in industry laboratories to facilitate routine frequency measurement and calibration services. Such services require evidence of traceability to internationally recognized standards if an accreditation is sought. And it is the responsibility of the operator to demonstrate his ability and practices to comply with respective requirements from international standards as EN ISO/IEC 17025. In this report we present an example of a full traceability chain for such a service, in detail comprising all links from the measurements with the so-called device under test via the operation of the laboratory standard to the internationally agreed standard, which is Coordinated Universal Time UTC. Some technical aspects of frequency measurements with counters requiring a closer look are addressed and discussed. Finally, a proposal for summarizing and reporting the uncertainty contribution is being made.