Browse Prior Art Database

Output Latching of Color and Video Signals for a Color Monitor Adapter

IP.com Disclosure Number: IPCOM000050052D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Kurtz, RC: AUTHOR

Abstract

Required synchronization of video and color information is provided through latching for delaying color signals.

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Output Latching of Color and Video Signals for a Color Monitor Adapter

Required synchronization of video and color information is provided through latching for delaying color signals.

Due to the high speed of a color adapter (a dot time on the order of 45 nsec), all dots are on for the entire dot time. Due to this short period, it is impossible to process video information through the logic paths required for blanking, reverse video, and other functions, and still maintain synchronization of the video information with the color data stored in a first set of data latches 1 included in an adapter.

To maintain synchronization, additional latches 2 and 3 are provided to delay the color signal for precisely as long as the video signal takes to be processed. The color delay and the video processing is done in dot time increments.

The video signal is processed in several stages, each designed to be completed in less than one dot time. At the end of each stage, the signal is latched for the beginning of the next function.

Following completion of video processing, the signal passes through a final latch 4 and appears at color logic 5 simultaneously with a arrival of the corresponding color signals. These signals, upon being gated through logic 5, may also be latched or sent directly to the monitor if the maximum delay is a small fraction of the dot time.

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