Subband acoustic feedback cancellation in hearing aids
US7020297B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 2003 |
| Grant date | Mar 28, 2006 |
| Priority date | — |
| Expiry date | May 13, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2430/03
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A new subband feedback cancellation scheme is proposed, capable of providing additional stable gain without introducing audible artifacts. The subband feedback cancellation scheme employs a cascade of two narrow-band filters Ai(Z) and Bi(Z) along with a fixed delay, instead of a single filter Wi(Z) and a delay to represent the feedback path in each subband. The first filter, Ai(Z), is called the training filter, and models the static portion of the feedback path in ith subband, including microphone, receiver, ear canal resonance, and other relatively static parameters. The training filter can be implemented as a FIR filter or as an IIR filter. The second filter, BI(Z), is called a tracking filter and is typically implemented as a FIR filter with fewer taps than the training filter. This second filter tracks the variations of the feedback path in the ith subband caused by jaw movement or objects close to the ears of the user.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.