Method and apparatus for automatic selection of scan rates for enhanced VGA-compatible monitors
US5285197A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1991 |
| Grant date | Feb 8, 1994 |
| Priority date | — |
| Expiry date | Aug 28, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2370/042
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for determining a plurality of video signal characteristics including analog video frequency, horizontal sync frequency and vertical sync frequency produced by a graphics controller providing the video signal to a video display monitor, includes a memory storing bits which correspond to a set of operating characteristics of the video display monitor, a first circuit coupled to the memory for producing voltage fluctuations on a line based on the stored bits in response to a signal which corresponds to a command to set the characteristics of the video signal provided to the video display monitor, and a second circuit for sensing the voltage fluctuations so as to permit determination of the set of operating characteristics. The first circuit includes a switch operatively coupled between a video line and ground to allow grounding of the video line based on the bits so as to produce the voltage fluctuations. The second circuit comprises a logic element for detecting the voltage fluctuations. A method for determining the operating capabilities of the video display monitor is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.