Josephson Arbitrary Waveform Synthesizer:electronics for a Quantum Standard for Ac Voltage

A new primary standard for AC voltage based on pulse driven Josephson junction arrays is under development. In this paper, preliminary spectral measurements and simulations are presented on a fast switching multiplexer unit built for the high precision synthesis of arbitrary waves. First order delta-sigma modulation is used to represent the wave to be synthesized. The first results are promising with respect to the conditions for high precision filtering of the quantization noise, i.e. a high signal-to-noise ratio is expected for the demodulated signal.