Ghost cancelling system
US4667241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1985 |
| Grant date | May 19, 1987 |
| Priority date | — |
| Expiry date | Jan 10, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/211
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A ghost cancelling system has a transversal filter connected to a video signal source to produce a ghost cancelling signal, composed with a video signal from the video signal source by use of a composer. A circuit is provided for detecting a ghost level during a predetermined period, including a masking pulse forming circuit and a detecting circuit for detecting a reference time point, a circuit for forming a standard waveform from the output of the detecting circuit, a circuit for subtracting the standard waveform from the video signal derived from the composer, and a circuit for detecting a ghost level from the output of the subtracting circuit. A signal derived from the masking pulse is supplied to the transversal filter for controlling its operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.