Methods and apparatus for reducing electromagnetic interference emission from a cathode ray tube video display system
US5157308A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 6, 1991 |
| Grant date | Oct 20, 1992 |
| Priority date | — |
| Expiry date | Aug 6, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Video signals for each primary color are delayed in time relative to every other primary color video signals. When displayed on a cathode ray tube ("CRT") display, the time delayed video signals will result in a separated color pattern for each image displayed. Separated color images are subsequently realigned through use of electron beam deflection controls affecting the horizontal and vertical displacement of electron beams for each color. Measurement of EMI at a far field point varies between zero (no EMI) and no reduction in measurable EMI, depending on the frequency of the video signals and the amount of time delay induced therein. In alternative embodiments, time shifting of video signals may be accomplished either by discrete filter components, simple propagation delay lines.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.