Determination of Transition Error Corrections for Low Frequency Stepwise-Approximated Josephson Sine Waves

This paper describes high-accuracy low-frequency ac voltage measurements using a programmable Josephson voltage standard based on a binary Josephson array. AC voltage synthesis is performed by switching between quantized Josephson voltages. The accuracy of a synthesized Josephson ac voltage is limited by the transition error. We present an experimental method for determination of a correction for the transition error. The method is based on the assumption of a linear frequency dependence of the transition error. Measurements up to 1 kHz have been performed. Using the transition error correction at different frequencies has shown a frequency-independent Josephson ac voltage step width.