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:
Jan. 02, 2001
Filed:
Apr. 25, 1997
Lawrence Tze-Leung Tse, Fremont, CA (US);
Chrontel, Inc., San Jose, CA (US);
Abstract
A high speed analog color key detection system is disclosed for video/graphics mixing that employs a high speed analog strobe comparator to compare the analog version of a pre-defined color key value to the stream of pixel values in an incoming analog graphics signal. When the comparator indicates a match, the display signal is switched from the analog graphics signal to an incoming analog video signal, enabling the analog video signal to be displayed within a graphics window. Comparisons are triggered by active transitions of a strobe signal with a frequency that is an integer k multiple of the frequency at which the pixel values are generated by a graphics card. Oversampling strobe signals (where the integer k is greater than one) enable comparisons to be performed on small segments of fat pixel values. The strobe signal is generated using a phase locked loop that is synchronized with a horizontal synchronization signal provided by the graphics card. The PLL also regenerates the pixel clock using the horizontal synchronization signal.