This paper describes a new calibration system developed at INMETRO to guarantee traceability of lowfrequency alternating current (ac) voltage calibrations (<1 kHz) to a programmable Josephson ac waveform synthesizer. The automated full-synchronous system allows the synchronization of a commercial calibrator or signal synthesizer with a programmable Josephson voltage synthesizer system to be made by employing digital sampling and signal processing techniques, aided by adaptive digital control. It allows accurate determination of the spectral content of ac signals with minimum human intervention. System operation, measurement techniques, and data analysis are detailed.
Index Terms-AC voltage, digital signal processing, Josephson, measurement standards, power, spectral analysis. Waldemar G. Kürten Ihlenfeld was born in União da Vitória, Brazil, in 1960. He received the B.Eng. degree from the Federal University of Paraná, Curitiba, Brazil, in 1983, and the M.Eng. and Ph.D. (magna cum laude) degrees in electrical engineering from Braunschweig Technical University, Braunschweig, Germany, in 1994 and 1997, respectively. He was with the Central Laboratory, LAC, Curitiba, from 1983 to 1999, a research institute of the Federal University of Paraná and the Power Utility Company of Paraná. From 1999 to 2013, he was with Physikalisch-Technische Bundesanstalt, Braunschweig, where he was involved in research and development of precision electronic circuits for ac power measurements, and mathematical modeling of sampling systems and investigating electro-thermal modeling of semiconductor devices. He is currently involved in developing sampling systems in the frame of the project Pronametro with the Instituto Nacional de Metrologia, Qualidade e he collaborated with the National Institute of Standards and Technology, Boulder, CO, USA, as a Guest Researcher in Josephson Systems. He is responsible for the dissemination of the Brazil legal volt and for maintaining internationally consistent and traceable voltage standards tied to the SI units. His current research interests include ac and dc Josephson voltage standards and quantum Hall systems and their applications in metrology, ac-dc transfer standards, and power and energy metrology.
