Control of horizontal frequency selection
US6400409B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 7, 1998 |
| Grant date | Jun 4, 2002 |
| Priority date | — |
| Expiry date | Aug 7, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N3/27
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus displays pictures from sources having a plurality of horizontal frequencies. A scanning generator is operable at the plurality of frequencies and comprises an oscillator generating a signal. A divider with two selectable counts is coupled to the oscillator and divides the signal by a first count to generate a horizontal drive signal. A horizontal scanning amplifier generates a scanning signal responsive to the horizontal drive signal coupled thereto. A controller is coupled to the scanning amplifier and to the divider. In response to selecting another of the plurality of frequencies, the controller monitors the scanning signal and responsive to its presence inhibits selection of a second of the selectable counts. In the absence of the scanning signal the controller enables selection of the second of selectable counts and the divider generates a horizontal drive signal representative of the another one of the plurality of horizontal scanning frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.