Video sync removal circuit
US5140422A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 16, 1990 |
| Grant date | Aug 18, 1992 |
| Priority date | — |
| Expiry date | Jul 16, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video sync removal circuit utilizes three bidirectional, voltage-controlled linear switches and a capacitor to remove the sync component from a video signal without introducing any non-linearities in the output video signal. The first of the switches is connected to pass the video signal through the circuit. The second switch is connected to pass the video signal to the capacitor and the third switch is connected to pass the voltage level on the capacitor to the output of the first switch. Two waveforms are generated to operate the switches: one waveform opens the first switch during the sync interval, thus blocking the sync component. The second waveform closes the second switch during a black level interval of the video signal, thus charging the capacitor to the black level. By closing the third switch during the sync interval (using the inverse of the first waveform), the black level voltage on the capacitor is substituted for the sync component in the output video signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.