Voltage lead errors in an AC Josephson voltage standard: Explanation in terms of standing waves

Abstract

A pulse-driven AC Josephson voltage standard generates calculable AC voltage signals at low temperatures, whereas measurements are performed with a device under test at room temperature. The voltage leads cause the output voltage to show deviations that scale with the frequency squared. So far, these deviations where thought of as a resonance, that could be damped, filtered or corrected for. However, in this paper calculations and measurements are presented that show that the problem is caused by standing waves. Solutions are thought for trying to minimize or compensate the reflection of waves.