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.

Date of Patent:
Nov. 06, 2007

Filed:

Dec. 13, 2004
Applicants:

Paul Kevin Hall, Lexington, KY (US);

Keith Bryan Hardin, Lexington, KY (US);

Brandon Robert Shields, Lexington, KY (US);

Inventors:

Paul Kevin Hall, Lexington, KY (US);

Keith Bryan Hardin, Lexington, KY (US);

Brandon Robert Shields, Lexington, KY (US);

Assignee:

Lexmark International, Inc., Lexington, KY (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05K 1/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A digital apparatus having a cable comprising a plurality of high-speed and low-speed signal carrying conductors, the conductors carrying the low-speed signals are bypassed to a signal ground with selected values of capacitance so as to become virtual signal ground return conductors for the high-speed signal conductors. The selected values of capacitance have a lower impedance then the characteristic impedance of the conductors in the cable. The cable may be a multi conductor cable, a ribbon cable, a flex cable, a twisted pair cable, etc. In a similar fashion, signal conductors on a printed circuit board, not having a separate ground plane layer, may create virtual signal ground returns from the low-speed signal carrying conductors that are proximate to the high-speed signal carrying conductors for reduction of radiated electromagnetic radio frequency interference.


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