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. 20, 2008
Filed:
Jul. 14, 2005
Hiep the Pham, Campbell, CA (US);
Mei Luo, San Jose, CA (US);
Hiep The Pham, Campbell, CA (US);
Mei Luo, San Jose, CA (US);
Altera Corporation, San Jose, CA (US);
Abstract
Transmitters or other devices coupled to transmission links may be required to detect the presence of receivers (or other devices) on the links before starting signal transmission. Methods and apparatus are provided for a transmitter to detect the presence of a receiver on a link. The detection relies on measuring changes in the electrical characteristics of the link at the output of the transmitter. Changes in capacitive or other loading at the transmitter output, caused by the coupling of a link and receiver to the transmitter, may be estimated by determining the rise time of a signal at the transmitter output. The rise time may be estimated in response to applying a common-mode voltage step at the transmitter output, for example. The transmitter may be able to determine the presence of a receiver on the link from changes in rise-time. Increasing transmitter output impedance, or measuring common-mode driver rise time, may increase the accuracy of the detection process.