The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 2006
Filed:
Sep. 12, 2002
David G. Lashley, Cartersville, GA (US);
Robert L. Doss, Ringgold, GA (US);
David G. Lashley, Cartersville, GA (US);
Robert L. Doss, Ringgold, GA (US);
Plantronics, Inc., Santa Cruz, CA (US);
Abstract
A full duplex telephone set for hearing impaired users includes a digital signal processor incorporating a pair of adaptive transversal filters to cancel line and acoustic echo feedback from the tip and ring signals of the set, and to condition and control the amount of a replacement side tone fed back to the receiver. This enables at least 50 dB of gain to be applied to the modified received signal without initiating unstable operation, or howl, in the set, and ensures that the received and side tone signals are heard by the user with equal comfort and clarity. The digital signal processor also enables additional enhancements to be made to the modified received signal that are beneficial to hearing impaired users, such as dynamic range compression, 'soft' limiting, and low level emphasis within selectable frequency bands.