Low-Motion Amplitude Operation of Lissajous Frequency Modulated MEMS Gyroscopes for Spurious Harmonics Reduction

This letter discusses and solves a relevant issue for Lissajous frequency modulated microelectromechanical system (MEMS) gyroscopes. Their working principle, under realistic control schemes, implies an undesired generation of spurious tones at twice the modulation frequency, which impairs system stability and bandwidth. A novel sensor design is proposed and coupled to an integrated circuit including an oscillator and a frequency to digital converter. The system is designed such that operation can occur at much smaller motion (down to 300 nm displacement amplitude) without, nevertheless, impairing significantly noise performance. In operation, the system shows a 51-fold reduction of the spurious harmonic while holding sub-10-mdps/√Hz input referred noise.