Abstract: The invention provides an analog-to-digital modulator for converting an analog input signal to a digital output signal. The filter is constructed and arranged to subtract the feedback signal from the external input signal and to filter the subtracted signal such that the filter output signal is attenuated when the subtracted signal is outside said pass band. A plurality of superconducting comparators and digital-to-analog converters are utilized in a time-interleaved mode. The feedback loop filter, digital-to-analog converters, and superconducting comparators are arranged within a feedback loop such that the filter output signal from the feedback loop filter is communicated to the superconducting comparators such that the comparators generate Single Flux Quantum pulses- at their digital outputs. The pulses are communicated to the digital-to-analog converters and therein converted to analog signals.

Abstract: Disclosed herein are circuits and methods for receiving SFQ data pulses from a superconductor signal source, and first and second clock pulses that are substantially equal in frequency but opposite in phase from clock signal sources, and for encoding and converting the SFQ data pulses into a phase-shift-keying coded dc output voltage. The circuit includes RSFQ T-RS flip-flop means, including quantizing means for storing a current in one of two stable states, which is responsive to the first and second clock pulses and the data pulse, for PSK coding the SFQ data pulses. The circuit also includes a SFQ/DC converter, which is coupled to the quantizing means of the RSFQ T-RS flip-flop means and is responsive to a state of the current stored in the quantizing inductance loop, for converting the PSK coded SFQ data pulses into a PSK coded dc voltage.