Josephson voltage standard based on single-flux-quantum voltage multipliers

A Josephson single-flux-quantum voltage/frequency multiplier circuit is proposed as the basic building block for a new generation of voltage standards. The circuit uses magnetic coupling to synchronize a series array of independent junction oscillators to the flux flow in a Josephson transmission line. A cascade of these circuits can multiply an arbitrarily low input frequency up to the frequency limit of the circuit ( approximately=250 GHz) and then add the voltages across approximately 30000 oscillators to generate precise voltages up to 10 V. Because the oscillators can be switched on and off with a bias current, the output voltage is rapidly programmable. A complete design for a voltage standard programmable in 1.2- mu V increments to a maximum of 10 V is proposed. Using existing fabrication technology, the circuit would cover a substrate area of about 1 cm/sup 2/ and use 67210 junctions.<>