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:
Oct. 15, 2002
Filed:
Feb. 23, 1999
Delbert Raymond Cecchi, Rochester, MN (US);
Richard L. Donze, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A digital data waveform is precompensated for attenuation through a transmission medium. First, during actual initial power-on or upon reconfiguration of a digital communication system, attenuation characteristics of the transmission medium are actually measured. The attenuation characteristics can be measured by measuring the length of the transmission medium, measuring the error rate of test packets having known frequency, measuring the slope of a test pulse at two separate threshold voltages, and/or measuring the error rate of a random signal packet. Upon determination of the magnitude of the attenuation characteristic, one of a plurality of registers corresponding to the range of values of the attenuation characteristic is selected. These registers have a plurality of pre-emphasis coefficients to be applied in the driver to each bit of a series of digital signal pulses as determined by the transition history of at least three sequential bits. Thus, dynamic and in-situ pre-emphasis can be determined and applied to signals to compensate for attenuation in the transmission network attenuation.