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Electro-mechanical feedback for realization of a mechanical spectrum analyzer

Publication Type:

Conference Paper


TRANSDUCERS, Solid-State Sensors, Actuators and Microsystems, 12th Innational Conference on, 8-12 June 2003, Boston, USA, Boston, MA, USA, p.1407 - 1410 (2003)



capacitors microactuators spectral analysers MEMS actuation capacitors driving electrical frequency electrically controlled signal electro-mechanical feedback functional coupling harmonic common mode voltage intrinsic nonlinear coupling microdomain monito


An important feature of MEMS, still underutilized, is the tight coupling
between the electrical and mechanical quantities in the micro domain.
This paper demonstrates the benefits of such a functional coupling
for a specific device: a real-time mechanical spectrum analyzer.
A surface micromachined accelerometer was designed, with a voltage-controlled
gain. By applying an harmonic common-mode voltage on the actuation
capacitors, the intrinsic nonlinear coupling performs a correlation
between the input acceleration and an electrically-controlled signal.
To reduce the distortion, a differential, twin-accelerometer scheme
is used. Time-multiplexed signal processing gives both the real and
the imaginary components of the selected spectral line. A mechanical
spectrum analyzer for low-frequency domains is obtained when the
driving electrical frequency is swept over the range of interest.
The operating principle has been confirmed by measurements, and is
expected to yield new opportunities in the field of low-power, low-cost
condition monitoring equipment.


E.Cretu, L.A. Rocha, R.F. Wolffenbuttel [2003] -_Electro-mechanical Feedback for Realization of a Mechanical Spectrum Analyzer_, in Transducers_03, The 12th International Conf. on Solid-State Sensors, Actuators and Microsystems, Boston, Ma, USA, June 8-12, pp1407-1410