Four terminal-pair impedance comparisons at high frequency

Calibration of impedance standards in the frequency range 100 KHz-10 MHz in necessary for traceability transfer to modern RLC bridges. A high-frequency coaxial impedance bridge, which can be employed for calibration impedance standards, is under construction: the paper is intended as a progress report on such bridge. The bridge is based on digital synthesis generators, and defines automatically the standards under comparison as four terminal-pair impedances. Different ratio arms, for calibration of like or unlike impedances can be employed; a Wheatstone-like ratio arm has been constructed and is under testing.