AC Josephson voltage standard up to 1 MHz

AC Josephson voltage standard up to 1 MHz

The development of an AC Josephson voltage standard (ACJVS) is based on the concept of modifying the DC Josephson voltage standard. In a pulse-driven Josephson system a digitally programmed high-speed pulse pattern causes a time-dependent voltage V(t) that varies in proportion to the relatively slowly varying pulse repetition rate f(t), V(t) = (h/2e)×f(t), where h is Planck’s constant and e is the electron charge. At present, the highest voltage obtained this way is 275 mV rms. Recently at VSL we presented the first precision measurements on a pulse-driven ACJVS for frequencies up to 1 MHz.  Read more....