Synchronization signal separating circuit
US4385319A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 13, 1980 |
| Grant date | May 24, 1983 |
| Priority date | — |
| Expiry date | Nov 13, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A synchronization signal separating circuit for deriving synchronization signals from a composite video signal, PA1 a clamp circuit which clamps the sync chip level of the composite video signal to a reference voltage level, PA1 a detection circuit which detects a voltage of the back porch part of the clamped composite video signal, PA1 a mixing circuit generating intermediate voltage between the reference voltage and the back porch part voltage as a threshold level, and PA1 a separating circuit which derives the synchronization signal from the clamped composite video signal based on the threshold level, thereby the accurate synchronization signal can be obtained by utilizing the abovementioned clamping level at the intermediate voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.