Cursor controlled page selection in a video display
US4587520A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 7, 1983 |
| Grant date | May 6, 1986 |
| Priority date | — |
| Expiry date | Apr 7, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0255
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A teletext system in which viewer function selection is accomplished by superposing a cursor on one of the displayed function words. The teletext/videotext receiver includes a ROM for storing page selection control symbols and a RAM for storing symbols and related addresses corresponding to all displayed page selection symbols. The RAM contents are compared with a cursor address signal to identify displayed page selection symbols that are at or near the cursor location. A page selection symbol, thus identified, is transferred from the RAM to the teletext/videotext system decoder as an information selection command in response to depression of a selection key whereby a minimum number of keys provide selection of a virtually unlimited number of system commands and a user may continuously monitor the displayed text while making selections thus reducing selection entry errors. Provision is made for altering the cursor position, shape and/or brightness upon a predetermined condition of proximity of the cursor with respect to a displayed system command symbol to verify the validity of the command to the user and to avoid positional ambiguities of the cursor relative to the displayed symb…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.