Amplitude-modulated electro-mechanical feedback system for silicon condenser microphones

A.G.H. van der Donk, P.R. Scheeper, W. Olthuis, P. Bergveld

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    For silicon condenser microphones, narrowing the air gap as a part of the miniaturization process causes a reduction of the bandwidth of the microphone. By introducing an actuator electrode on the diaphragm for electro-mechanical feedback, it is possible to increase the bandwidth of condenser microphones with a narrow air gap. A feedback system is presented, which uses an amplitude-modulated actuator signal with a carrier frequency far above the audio-frequency range. With feedback, the bandwidth of the microphone is increased by at least a factor 10.
    Original languageEnglish
    Pages (from-to)211-214
    Number of pages4
    JournalJournal of micromechanics and microengineering
    Issue number3
    Publication statusPublished - 1992

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