Method and apparatus for sensing an audio signal that is sensitive to the audio signal and insensitive to background noise
US6072882A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1997 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Aug 29, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2410/05
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for sensing audio frequency-pressure modulation of the moisture content of the atmosphere caused by a moisture-laden audio source, such as a live human voice, is disclosed. A first light emitter is provided to generate a first light beam. An audio source that emits moisture, and the environment, modulate the first light beam to generate a first modulated light beam. A first detector is provided to detect and demodulate the first modulated light beam to recover an uncompensated audio signal. A second light emitter is provided to generate a second light beam. The second light beam is modulated by the environment and not by the audio source to produce a second modulated light beam. A second detector is provided to detect and demodulate the second modulated light beam to recover the signal component caused by environmental conditions. A differential amplifier is provided to generate a compensated output signal representing the difference between the uncompensated audio signal and the signal component caused by environmental conditions. The output signal can be transmitted for amplification, distribution, and/or recording.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.