Computer graphics processing and selective visual display system – Computer graphic processing system
Reexamination Certificate
2000-08-04
2004-05-11
Tung, Kee M. (Department: 2676)
Computer graphics processing and selective visual display system
Computer graphic processing system
C345S600000
Reexamination Certificate
active
06734860
ABSTRACT:
FIELD OF THE INVENTION
The invention generally relates to computer graphics processing and, more particularly, the invention relates to graphics accelerators having videodriving capability from various types of digital to analog converters (“DACs”).
BACKGROUND OF THE INVENTION
Many computer systems utilize graphics accelerators to process graphics request code. A graphics accelerator may include one or multiple parallel processors. In order to display a graphical image, the data produced by the processor (or processors) must be transmitted to a display device. Accordingly, graphics processors typically utilize a back end system to format the processed graphics request code to be displayed on a display device such as a cathode ray tube monitor. Such formatting may include gamma correction to compensate for,nonlinear characteristics of the drive electronics of the monitor, the addition of cursor data and the conversion of digital graphics data to analog graphics data. Accordingly, back end systems commonly include a random access memory/digital to analog converter (“RAMDAC”) that applies gamma correction and adds cursor data to processed graphics request code. It is possible, however, that the internal RAMDAC of the back end system may not function acceptably or meet the requirements of the graphics processing system. Often, the result is that a particular graphics processor will no longer be useable.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, an apparatus for processing a graphical data stream for display on a display device includes a processor for determining display characteristics of the graphical data stream, a first conversion module for converting the graphical data stream in a first format to a second format, and a second conversion module for converting the graphical data stream in a first format to a second format. A first data path directs the graphical data stream through the first conversion module and a second data path directs the graphical data stream through the second conversion module. To that end, in a preferred embodiment, the apparatus further includes a switching system for alternatively connecting the first conversion module through the first data path and the second conversion module through the second data path.
In preferred embodiments, the first conversion module and the second conversion module may include a gamma correction module that applies gamma correction operations to the graphical data stream, a cursor unit that adds cursor data to the graphical data stream and a digital to analog converter for converting digital graphical data streams to analog graphical data streams. In addition, the first conversion module and the second conversion module may be formed on different integrated circuits.
In accordance with another aspect of the invention, an apparatus for processing a graphical data stream for display on a display device includes a processor for determining display characteristics of the graphical data stream, a conversion module which includes a first digital to analog converter, the conversion module for converting the graphical data stream in a first format to a second format. The apparatus also includes a second digital to analog converter coupled to the input of the conversion module. A first data path directs the graphical data stream through the first digital to analog converter and a second data path directs the graphical data stream through the second digital to analog converter. To that end, in a preferred embodiment, the apparatus includes a switching system that alternatively connects the first digital to analog converter through the first data path and the second digital to analog converter through the second data path.
In accordance with another aspect of the invention, a graphics processor for processing a graphical data stream for display on a display device includes a back end unit for formatting the graphical data stream for display on the display device. The back end unit includes a first conversion module for converting the graphical data stream in a first format to a second format. The processor also includes a second conversion module coupled to the first conversion module input. The second conversion module converts the graphical data stream which is in a first format to a second format. A first data path, coupled with the first conversion module input and the display device, directs the graphical data stream through the first conversion module and a second data path, coupled with the first conversion module and the display device, directs the graphical data stream through the second conversion module.
In one embodiment, the first conversion module and the second conversion module include a gamma correction module for applying gamma correction operations to the graphical data stream, a cursor unit for adding cursor data to the graphical data stream and a digital to analog converter for converting digital graphical data streams into analog graphical data streams. In addition, the first conversion module and the second conversion module may be formed on different integrated circuits.
In a further embodiment, the graphics processor further includes a switching system coupled to the first conversion module and the second conversion module. The switching system alternately connects the first conversion module through the first data path and the second conversion module through the second data path.
In accordance with yet another aspect of the invention, a graphics processor for processing a graphical data stream for display on a display device includes a back end unit for formatting the graphical data stream for display on the display device. The back end unit includes a conversion module which includes an input for receiving the graphical data stream, a first digital to analog converter for converting digital graphics data streams into analog graphics data streams and an output for transmitting the graphical data stream to the display device. The graphics processor also includes a second digital to analog converter coupled to the input of the conversion module. The second digital to analog converter converts digital graphics data streams to analog graphics data streams. A first data path, coupled to the input of the conversion module and the display device, directs the graphics data stream through the first digital to analog converter and a second data path, coupled with the input of the conversion module and the display device, directs the graphical data stream through the second digital to analog converter.
In one embodiment, the conversion module also includes a gamma correction module for applying gamma correction operations to the graphical data stream and cursor unit for adding data to the graphical data stream. A switching system may be coupled to the first digital to analog converter and the second digital to analog converter. The switching system alternately connects the first digital to analog converter through the first data path and the second digital to analog converter through the second data path. In a further embodiment, the first digital to analog converter and the second digital to analog converter are formed on different integrated circuits.
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Potter Michael
Whitmore Clifford A.
3Dlabs Inc. Ltd.
Arnall Golden & Gregory LLP
Tung Kee M.
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