Bandpass sigma-delta modulator employing high-Q resonator for narrowband noise suppression

A superconducting bandpass sigma-delta modulator for use in analog-to-digital converters for converting an analog input signal to a digital output signal, said modulator comprising:

• input means for receiving the analog input signal;
• high Q resonator means coupled to said input means;
• sampling pulse generator means for generating sampling pulses;
• quantizer means coupled to said sampling pulse generator means and to said resonator means for quantizing the input signal and producing an output signal representative of the analog input signal, said resonator means for presenting said quantizer means with a low impedance at a resonant frequency, wherein said digital output signal is provided at a clock frequency that is substantially equivalent to the switching frequency of a single Josephson junction.

A superconducting bandpass sigma-delta modulator for use in analog-to-digital converters for converting an analog input signal to a digital output signal, said modulator comprising:

• coupling means for receiving the analog input signal and producing a coupled signal;
• high Q resonator means coupled to said coupling means for producing a resonant signal;
• sampling pulse generator means for generating sampling pulses;
• quantizer means coupled to said sampling pulse generator means and to said high Q resonator means for quantizing the resonant signal and producing an output signal representative of the analog input signal, wherein said digital output signal may be provided at a clock frequency that is substantially equivalent to the switching frequency of a single Josephson junction, said high Q resonator means further being provided to shunt the quantizer means with a low impedance and low fractional energy loss per cycle at a center frequency of the input signal.