Estimating direction of arrival from plural microphones
US8565446B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 12, 2010 |
| Grant date | Oct 22, 2013 |
| Priority date | — |
| Expiry date | Jun 27, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2430/23
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A noise suppression system includes plural microphones, a fixed beam former, a blocking matrix, plural adaptive filters, and a direction of arrival circuit coupled to the adaptive filters that prevents the filters from adapting in the presence of a signal in the look direction. The direction of arrival circuit causes the filters to adapt more quickly in the absence of a signal in the look direction. A pair of adjustable gain circuits is coupled to each microphone. A first adjustable gain circuit from each pair is calibrated during the presence of a desired signal and a second adjustable gain circuit from each pair is calibrated during the presence of an interfering signal. A fixed null-forming circuit is coupled to a first pair of variable gain circuits and an adaptive null forming circuit is coupled to a second pair of adjustable gain circuits. The ratio of the gains of the null forming circuits is used as a control signal. Successive ratios are averaged with a variable smoothing constant and a control signal is derived from the averaged ratios.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.