Circuit for measuring the resonant frequency of nanoresonators

摘要

The present disclosure relates to nanoresonator oscillators or NEMS (nanoelectromechanical system) oscillators. A circuit for measuring the oscillation frequency of a resonator is provided, comprising a first phase-locked feedback loop locking the frequency of a controlled oscillator at the resonant frequency of the resonator, this first loop comprising a first phase comparator. Furthermore, a second feedback loop is provided which searches for and stores the loop phase shift introduced by the resonator and its amplification circuit when they are locked at resonance by the first loop. The first and the second loops operate during a calibration phase. A third self-oscillation loop is set up during an operation phase. It directly links the output of the controllable phase shifter to the input of the resonator. The phase shifter receives the phase-shift control stored by the second loop.

主权项

1. An electronic circuit for measuring an oscillation frequency of a resonator, comprising a first feedback loop which is a phase-locked loop comprising the resonator, a controlled oscillator and a first phase comparator, said first feedback loop locking an output frequency of the controlled oscillator at a resonant frequency of the resonator, said electronic circuit further comprising:
a second feedback loop comprising a controllable phase shifter, a second phase comparator receiving the output of the controlled oscillator and the output of the controllable phase shifter, and the second phase comparator supplying a control signal for the phase shifter acting in a direction tending to reduce to zero a phase shift between its inputs, means being provided for storing the obtained phase-shift control signal, a self-oscillation loop comprising the resonator and the controllable phase shifter and linking the output of the controllable phase shifter to the input of the resonator, and means for activating the first feedback loop and the second feedback loop and deactivating the self-oscillation loop, during a calibration phase, and for deactivating the first and the second feedback loops and activating the self-oscillation loop, during an operation phase, the control signal of the controllable phase shifter during the operation phase being the control signal stored at the end of the calibration phase.