Feedback cancellation improvements
US6219427A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1998 |
| Grant date | Apr 17, 2001 |
| Priority date | — |
| Expiry date | Sep 12, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2430/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Feedback cancellation apparatus uses a cascade of two filters along with a short bulk delay. The first filter is adapted when the hearing aid is turned on in the ear. This filter adapts quickly using a white noise probe signal, and then the filter coefficients are frozen. The first filter models parts of the hearing-aid feedback path that are essentially constant over the course of the day. The second filter adapts while the hearing aid is in use and does not use a separate probe signal. This filter provides a rapid correction to the feedback path model when the hearing aid goes unstable, and more slowly tracks perturbations in the feedback path that occur in daily use. The delay shifts the filter response to make the most effective use of the limited number of filter coefficients.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.