Patent ID: 11888445
Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 23:
24. A system, comprising:
a plurality of quantum bits;
an arbitrary waveform generator system comprising a plurality of arbitrary waveform generator channels, wherein each arbitrary waveform generator channel is coupled to a respective quantum bit of the plurality of quantum bits, and configured to generate a radio frequency signal to control operation of the quantum bit;
a phase-locked loop system configured to generate a local oscillator signal which is utilized by modulation systems in the respective arbitrary waveform generator channels;
wherein the phase-locked loop system comprises:
voltage-controlled oscillator; and
an analog differential tuning control system comprising a differential charge pump and a loop filter, wherein the analog differential tuning control system is configured to generate a differential control voltage to tune an output frequency of the voltage-controlled oscillator;
wherein the voltage-controlled oscillator comprises a resonant tank circuit;
wherein the resonant tank circuit comprises a variable capacitor circuit comprising a plurality of variable capacitor devices connected in parallel to first and second tank nodes of the resonant tank circuit;
wherein each variable capacitor device comprises first and second control paths which are configured to enable differential control of the variable capacitor device in response to the differential control voltage applied to first and second transistors of a same doping type in the first and second control paths, respectively, wherein the first and second transistors are configured as voltage variable resistors for tuning a capacitance of the variable capacitor device in response to the differential control voltage.