Title:
SUBBAND ACOUSTIC FEEDBACK CANCELLATION IN HEARING AIDS
Document Type and Number:
WIPO Patent Application WO2001022775
Kind Code:
A3
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)ng 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 i 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 i subband caused by jaw movement or objects close to the ears of the user.
Inventors:
FANG XIAOLING
WILSON GERALD
GILES BRAD
WILSON GERALD
GILES BRAD
Application Number:
PCT/US2000/024230
Publication Date:
December 06, 2001
Filing Date:
August 31, 2000
Export Citation:
Assignee:
SONIC INNOVATIONS INC (US)
International Classes:
G10L19/00; G10L19/02; G10L19/26; G10L21/0208; G10L21/0232; H04R25/00; (IPC1-7): H04R25/00; H04R3/02
Domestic Patent References:
| WO1999026453A1 | 1999-05-27 | |||
| WO1998047314A2 | 1998-10-22 | |||
| WO1996035314A1 | 1996-11-07 |
Foreign References:
| EP0930801A2 | 1999-07-21 |
Other References:
WYRSCH S. ET AL: "ADAPTIVE FEEDBACK CANCELLING IN SUBBANDS FOR HEARING AIDS", PHOENIX, AZ, MARCH 15 - 19, 1999,NEW YORK, NY: IEEE,US, 15 March 1999 (1999-03-15), pages 921 - 924, XP000900272, ISBN: 0-7803-5042-1
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