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:
Sep. 05, 2000
Filed:
Oct. 06, 1997
Andrew L Norrell, Nevada City, CA (US);
Mark A Waldron, Gurnee, IL (US);
Vladimir G Parizhsky, Chicago, IL (US);
Carl H Alelyunas, Nevada City, CA (US);
Scott A Lery, Nevada City, CA (US);
3COM Corporation, Santa Clara, CA (US);
Abstract
A method of detecting the presence of signal impairments that introduce distortion in one or more time slots of a communication link by comparing a received training sequence of signal points with hypothetical received signal points, where the hypothetical points are predistorted versions of the training sequence, and are based on the known, predetermined training sequence of signal points. A detection matrix is formed where one dimension of the matrix corresponds to a time slot within a frame, preferably six time slots to a frame, and the other dimension corresponds to a particular impairment, or combination of impairments. The individual signal impairments are generally one or more of the following: robbed bit signaling where the robbed bit is replaced with a logic `0`; robbed bit signaling where the robbed bit is replaced with a logic `1`; robbed bit signaling where the robbed bit is replaced with a logic `1/2`; 3 dB digital attenuator; 6 dB digital attenuator. The hypotheses are based on individual impairments and combinations/permutations of these impairments. The minimum value of each column (corresponding to a time slot within the frame) of the detection matrix indicates the type of impairment in that time slot.