Phase noise analysis of micromechanical silicon resonant accelerometer

Abstract

The phase noise in micromechanical silicon resonant accelerometer (SRA) can perturb its frequency output and determines the minimum detectable change in acceleration (sensor resolution). In order to improve the resolution and optimize the sensor performance, the phase noise of SRA is studied in this paper. Theoretical model of phase noise of SRA is set up, especially the effect of the automatic gain control (AGC) circuit in oscillator to phase noise in low frequency range (1/f3 phase noise and 1/f5 phase noise) is analyzed, and the restriction of resolution performance arising from the 1/f3 phase noise caused by AGC is also illustrated. Phase noise experiments are then performed on a SRA prototype developed in MEMS Inertial Technology Research Center and validate the model. Compared to the previous work, the phase noise model in this paper matches the experiments results more precisely, and could provide guidance and reference for design in MEMS inertial device.