Terminal having user selectable faster scanning
US4616260A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1983 |
| Grant date | Oct 7, 1986 |
| Priority date | — |
| Expiry date | Feb 28, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G5/18
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus and method for generating monitor synchronization signals in a terminal capable of operating at either a 31.5 Khz or 15.75 Khz horizontal video scan rate is disclosed. A first set of counters count incremental locations along each horizontal scan line. The outputs of these counters are provided to a memory which provides a blanking signal and three synchronization signals. The memory also provides a clocking input to a second set of counters which count horizontal scan lines. These second counters are preloaded to values which depend on the scan mode selected, the frame being displayed, the refresh rate and whether a vertical video or vertical blanking operation is underway. A second memory receives the outputs of the second counter set, the frame being displayed and the refresh rate signal and provides selection inputs used to choose the signals to be provided as the composite blanking and composite monitor synchronization signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.