Search and lock technique for reliable acquisition of data transmitted via television signals
US5003390A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 26, 1990 |
| Grant date | Mar 26, 1991 |
| Priority date | — |
| Expiry date | Mar 26, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/035
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is directed to the implementation of a reliable data communications system using the horizontal scan lines of video signals, and is particularly concerned with the minimization of problems which are caused as a result of false acquisition of horizontal scan lines and missed or dropped lines. In accordance with the present invention, a two-tier approach to receiving data transmitted via television signals is used. The two-tier approach includes a search mode and a lock mode. The present system operates on the principle that if a horizontal scan line (or lines) has been perfectly identified to contain data for successive fields of a video signal, then this scan line (or lines) can be presumed to be a valid data bearing scan line (or lines) in fields of the video signal yet to be received. The lock mode is then utilized to favor the retrieval of what would otherwise be missed or dropped horizontal scan lines were the system operating in the more restrictive search mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.