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. 04, 1990
Filed:
Aug. 22, 1989
Jozef B Baran, Moreno Valley, CA (US);
AST Research, Inc., Irvine, CA (US);
Abstract
A multi-layer printed circuit board is constructed to suppress radio frequency interference (RFI) generated by high frequency clock and data signals therein. Suppression is achieved by positioning clock lines carrying the clock signal on a first voltage reference layer proximate to a second voltage reference layer. The two layers shield the clock signal from the signal lines on other layers. Noise may be further reduced by forming bridges in the second voltage reference layer proximate to the clock lines so that the bridges span the width of the clock line. Capacitors are also preferably utilized to further suppress radiated noise. The capacitors provide AC coupling between the first and second voltage reference layers so that a low impedance path is provided for high frequency noise generated by the clock signal. The second voltage reference layer thus operates as an effectively continuous shield between the bridges.