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:
Oct. 18, 1988
Filed:
Mar. 11, 1985
David L Henderson, Colorado Springs, CO (US);
Carl M Stanchak, Colorado Springs, CO (US);
NCR Corporation, Dayton, OH (US);
Abstract
A multiplying digital to analog converter using ladder networks and binary weighted load compensation to allow integration and video frequency operation. In one form, the circuit is configured from field effect transistors which incorporate by virtue of their structural and operational characteristics both the switching and resistive functions of R-2R ladder networks. The circuit is used to convert digital format words representing intensity and color (red, green and blue) into analog red, green and blue display drive signals. According to that configuration, the output of the digital to analog intensity word converter serves as the reference for the three digital to analog color word converters. Loading effects attributable to differences in the bit content of the color words are offset by a binary weighted switched load which is responsive to a digital compensation word. The switched load is also connected to the output of the intensity word converter. This circuit configuration provides an implementation by which the color (hue and saturation) in analog form can be held constant while the intensity of the color is selectively varied.