Progress On Ptb'S Pulse-Driven Josephson Impedance Bridge Combined With An Ac Quantum Hall Resistance

Pulse-driven Josephson arrays successfully demonstrated their high potential for impedance metrology in the last years. With their high spectral purity and fundamental accuracy, they are perfectly suited for impedance measurements over the whole complex plane. PTB's two-terminal impedance bridge is equipped with new electronics to extend the frequency range, to increase the signal amplitude and to simplify the setting of the phase angle. A 1:1 ratio measurement of 10 nF capacitance standards has been carried out between 246 Hz and 40 kHz at a signal amplitude of 75 mV (RMS). The value of a 10 nF capacitance standard is traced back to the ac quantum Hall resistor at PTB using 100 mV (RMS) signal amplitude.