Superconducting sigma-delta analog-to-digital converter

This patent describes a superconducting sigma-delta analog-to-digital converter for converting an analog input signal to a digital output signal. It comprises a superconducting inductor to which the analog input signal is applied to produce an inductor current; a Josephson junction connected in series with the superconducting inductor and through which the inductor current flows; a pulse generator adding sampling current pulses to the inductor current to produce a total current flowing through the Josephson junction; and output means generating from the voltage pulses the digital output signal