Active Electrostatic Compensation of Micromechanical Resonators Under Random Vibrations

This letter presents a method of using electrostatic tuning to actively diminish the phase noise in a micromechanical oscillator that is caused by external vibrations. An accelerometer measures the acceleration applied to a micromechanical resonator and generates a compensation signal that is added to the bias voltage to remove the induced phase error. The proposed method achieves an 80.6% reduction of the acceleration sensitivity on average for a sinusoidal acceleration from 50 to 250 Hz with single-anchored double-ended tuning fork resonators. The rejection of phase noise due to random vibrations in the band from 15 to 80 Hz is also demonstrated.