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. 29, 2000
Filed:
Mar. 17, 1997
Mac L Hartless, Forest, VA (US);
David W Brown, Concord, VA (US);
David P Cullen, Lynchburg, VA (US);
John V Hughes, Carbondale, IL (US);
Darryl W Royster, Lynchburg, VA (US);
Ericsson Inc., Research Triangle Park, NC (US);
Abstract
These and other objects of the present invention are achieved using an Adaptive Multi-Path Filter (AMPF) which eliminates audibly objectionable click noise generated at the output of an FM discriminator to prevent audible distortion or other corruption of the desired signal which may include voice and low speed digital data. Clicks are detected at the discriminator output using a colored-noise, matched filter designed and adapted to the click signature/shape as well as to the desired signal characteristics. The colored-noise matched, filter output is then compared to an adaptive threshold. When the threshold is exceeded, a click is registered as detected. Click duration is then estimated. An estimate of the desired signal is generated and that replaces the originally received data signal estimate within the click duration region. Using characteristics of the desired signal just before and after the detected click noise, the adaptive filter accurately estimates the parameters of the desired signal so that the replacement signal fairly models what the desired signal would have looked like had the click not occurred. In this way, a substantial portion of the desired signal is preserved.