Horizontal sync pulse control circuit for video tape recorder utilizing pulse code modulation
US4507687A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1982 |
| Grant date | Mar 26, 1985 |
| Priority date | — |
| Expiry date | Aug 19, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/935
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A horizontal sync pulse control circuit for a video tape recorder of the type utilizing pulse code modulation in a standard format, where there is a fixed time interval between each horizontal sync pulse and the beginning of the data pulse train for the corresponding video line. Delay circuitry and associated signal process circuitry is used to monitor this time interval. When the monitored time interval between the horizontal sync pulse and the first data pulse for the corresponding line differs from the correct time interval by one bit or less, the position of the horizontal sync pulse is re-synchronized utilizing a clock locked to the video signal. When the interval between the horizontal sync pulse and the first data pulse of the corresponding line exceeds one bit, the horizontal sync pulse is blanked, so that noise which would otherwise be produced by an incorrect horizontal sync pulse is eliminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.