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:
May. 21, 2002
Filed:
Mar. 09, 1999
Bruce M. Furman, Palo Alto, CA (US);
Charles M. Allen, Sunnyvale, CA (US);
Maxim Integrated Products, Inc., Sunnyvale, CA (US);
Abstract
The present invention overcomes ISI by precompensating for the anticipated high-frequency energy losses in the transmission media. This precompensation is accomplished using a preemphasis waveform, i.e., driving the differential signal to a value larger than normal on a signal edge. Preemphasis increases the slew rate of edges inside data with a lot of transitions relative to data with fewer transitions, thereby compensating for the low-pass effects of the transmission cable. The present invention further contemplates adaptive control for ensuring that varying operating conditions do not effect preemphasis waveform generation. The first approach involves tracking the operation of a replicate driver for each main driver and adaptively controlling each main driver depending upon feedback from the replicate driver. A second approach, that is both more complicated and more effective, involves measuring the signal and the line impedance at the output of the main driver and adaptively controlling the main driver in response.