Realization of Low Frequency Power Standard at NPLI

Abstract

National Physical Laboratory (NPLI) India is the premier research and development center and the National Metrology Institute, which provides traceability in measurements by calibration throughout the country. Microwave power is one of the important parameter in electrical metrology. The coaxial microcalorimeter at NPLI is being used as the primary standard of microwave power from 10 MHz to 18 GHz. The standards for low frequency (LF) voltage are established by assigning AC–DC transfer difference to multijunction thermal voltage converters. The range of frequency of these standards is from 10 Hz to 1 MHz at NPLI. The measurement results, below 10 MHz by calorimetric technique are not reliable. Hence, there is a need for LF power standard at 1 MHz, which has been realized using twin resistance coaxial power mount traceable to LF voltage standard. In this paper a description of measurement technique, traceability, calibration results along with uncertainty has been explained.