Research on AC voltage measurement method based on high-speed comparison and Josephson Junction Arrays Voltage Standard

Currently, the primary means of quantum traceability for alternating current voltage involve the use of either the Programmable Josephson Junction Arrays Voltage Standard (PJVS) or the Pulse-driven Josephson Junction Voltage Standard (JAWS). The former is limited by its physical conditions and cannot synthesize high-frequency signals, while the latter exhibits a complex system structure and low accuracy in voltage waveform synthesis. To expand the application of quantum voltage standards in high-frequency signal domains, an AC voltage measurement method is presented based on the high-speed comparison and Josephson Junction Arrays Voltage Standard (JVS). The method in the JVS with multiple tap, form the equal voltage difference, using multiple groups of high-speed comparator directly compare the measured voltage signal and the tap output voltage, using multi-channel picosecond level precision time timer record each group of comparator output jump time and its corresponding quantum voltage threshold, finally through the heterogeneous discrete Fourier interpolation method to reproduce the measured signal waveform. Simulation results show that the measurement accuracy level of the reproduced waveform can reach 10⁻⁵ level when the signal amplitude of the measured signal is 3V and its frequency range of 5 kHz to 500 kHz. Therefore, the quantum AC voltage measurement method proposed in this paper can be applied to high-frequency voltage signal measurement scenarios. At the end of the paper, system error analysis is performed. And the results show that the main error of this method comes from the malalignment voltage of the comparator. If the latest comparator reported, the misalignment voltage can be reduced from mV to hundred μV, the measurement accuracy level of this method is expected to be reduced to 10⁻⁶ or even 10⁻⁷, which is better than JAWS 10⁻⁵-level. Therefore, the research results of this paper are expected to be an excellent method of measuring AC voltage.