Quality Assurance for Josephson Array Voltage Standards

A series of quality assurance (QA) procedures for the Josephson array voltage standard (JAVS) has been implemented to improve the efficiency and quality of dc voltage measurements in the National Metrology Centre, Agency for Science, Technology, and Research (A*STAR), Singapore. Periodic direct comparisons between two JAVS systems are required in the QA procedure to ensure accurate representation of the volt for calibration of secondary standards. QA-oriented setup and procedure are developed for better control of microwave power and locking frequency when using the millimeter-wave synthesizer. The analysis-of-variance method and the Monte Carlo method are implemented in data reporting and uncertainty evaluation processes.