Method and apparatus for sound responsive tactile stimulation of deaf

Abstract

A tactile aid for deaf individuals includes a conveniently wearable array of vibration transducers mounted on a flexible carrier strip so as to be positionally biased toward the individuals's skin. Each transducer includes an enclosed magnetically vibratable cantilevered beam, an angled mounting slot to effect the positional bias mounting on the strip, and contact pads rather than conventional pin connectors to both reduce mass and facilitate electrical connection to contact pads on carrier strips in the form of printed circuit boards. Received acoustic signals are processed in at least first and second formant circuits each sub-divided into plural sub-bands corresponding to the number of transducers. In each formant circuit the corresponding formant frequency and amplitude are measured, averaged over a predetermined number of cycles, and a voltage corresponding to the measured amplitude is provided on a corresponding sub-hand channel to pulse width modulate a pulse train employed to excite the transducers. Spectral resolution can be increased by averaging the amplitude/frequency measurements over fewer cycles. Glottal pulses in the speech signal are monitored to provide a glottal rate signal at a stepped down frequency related to the actual glottal rate. The channel amplitude is modulated by the glottal signal to cause alternation of transducer excitation at the related glottal rate. Additional formants may be detected to derive additional information in the excitation signal.