Acoustic Transducers for Automatic Speech Recognition

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Acoustic Transducers for Automatic Speech RecognitionObjectiveThe research objective is to transform automatic speech recognition in noisy environments by active noise cancellation. The approach is integrate into one package (1) a bank of acoustically filtered microphones that are based on a high quality-factor resonance of a microphone diaphragm and (2) a microspeaker on a silicon chip to improve the signal-to-noise ratio through active noise cancellation. Intellectual MeritThis research will lead to a microspeaker on a silicon chip for sound generation next to a microphone to actively cancel noise, and thus to discriminate noise from speech. One approach for the microspeaker will be to use an elastically compliant polymer layer to form a cantilever-like diaphragm. This research will also develop a resonant microphone with quality factor of about 40 with resonant frequencies that can electrically be tuned. A bank of the resonant microphones with extremely low noise floor will render bandpass-filtered signals at the microphone level, which will be accurate representations of acoustic powers at those specific frequencies.Broader ImpactThe research will greatly impact voice command systems (as well as cellular phones) in subways, airports, running automobiles, battlefields, etc. The tunable resonant microphone and the microspeaker will find broad applications to human-machine interfaces. The proposed activity will also include (1) incorporation of the research results into a lab course on acoustic microelectromechanical systems and (2) research involvement of students from underrepresented groups.