Automation of NIST frequency calibrations at remote sites

NIST has performed remote frequency calibrations since 1984 through the NIST Frequency Measurement and Analysis Service (FMAS). Customers who require traceability to the NIST frequency standard can subscribe to the FMAS by paying a monthly calibration fee to NIST. The calibrations made at the customer's site are automated by a frequency measurement system that NIST supplies to each customer. NIST provides training and phone support for the measurement system, and obtains and validates each customer's data through a modem hookup. Each customer receives a monthly calibration report that documents traceability to NIST. This paper provides a brief introduction to frequency calibrations, describes the measurement system delivered to the customer's site and what it does, and explains how NIST operates the service and reports calibration results. It also details some future enhancements to the service that are now under development.