Magnetic recording and playback apparatus for teletext signals
US4695900A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1985 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Apr 12, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/8238
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording and playback apparatus for teletext signals which accurately records and reproduces the teletext signal superposed within the vertical blanking period of television signal, includes at least one wide band filter, at least one narrow band filter, a filter selection switch which switches at least one filter for a luminance signal processing system to the wide band filter and at least one filter for a chrominance signal processing system to the narrow band filter, and a control circuit which generates a control signal for controlling the filter selection switch. The control circuit generates the control signal only during a specified period where the teletext signal is superposed. In case a comb filter is used, a switch is provided for selectively passing an output of the comb filter and an input video signal to the succeeding stages and a control circuit for producing a control signal to allow the input video signal to pass during a specified period where the teletext signal is superposed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.