Automated system for inductance realization traceable to AC resistance with a three-voltmeter method
Luca Callegaro, Vincenzo D’Elia · 2002
An automatic system for the comparison of unlike impedances in the range 1/spl Omega/-10 M/spl Omega/, based on the three-voltage method, has been constructed and is undergoing extensive tests as a system for realization of the inductance scale at IEN in the range 100 /spl mu/H-10 H at frequencies of 120 Hz and 1 kHz. The main features of the system are: a two-phase direct-digital synthesis generator for energizing the standards, complete four terminal pair definition of the standards with automatic servosystems, the use of a single high-accuracy voltmeter and a switching unit, optical links for the distribution of frequency references. Measurements at metrological level have been performed at 1 kHz with inductors in the range 10 mH-1 H.