A system-level comparison of amplitude-vs frequency-modulation approaches exploited in low-power MEMS vibratory gyroscopes

Conventional MEMS vibratory gyroscopes rely on detecting the Coriolis-induced displacement amplitude along three orthogonal modes of a micro-mechanical structure. In recent years, an alternative approach based on frequency modulation, where the rate modulates the resonance frequency of the structure, has been proposed. This work tackles, from a system-level point of view, a comparison between the two solutions, aiming at a fair review of their main properties, advantages and drawbacks. The manuscript mainly focuses on low-power architectural aspects, on the sensitivity of the transduction principle against process and temperature variations, and on critical aspects related to the analog-to-digital conversion and the signal demodulation. Examples of experimental results enrich the discussion.