Reducing acoustic feedback with digital modulation
US6252967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1999 |
| Grant date | Jun 26, 2001 |
| Priority date | — |
| Expiry date | Jan 21, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R3/02
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Sound is converted into an electrical signal by a microphone and is converted into an inaudible, digitally modulated signal that is combined with the electrical signal from the microphone, amplified, and converted into sound waves by a speaker. Any sound traveling from the speaker back to the microphone includes the inaudible component representing the original sound. The inaudible component is separated from the audible components, and the original sound is reconstructed in a digital demodulator. The reconstructed original sound is subtracted from the signal from the microphone, thereby reducing any echo and canceling feedback. Digital modulation includes any form of shift keying, including coherent and noncoherent techniques for modulating frequency, phase, or amplitude.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.