Method and apparatus for reproduction of video signals from magnetic tape at a tape transport speed differing from that of recording
US4791499A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 2, 1986 |
| Grant date | Dec 13, 1988 |
| Priority date | — |
| Expiry date | Dec 2, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/937
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a magnetic tape machine which can be played to reproduce television pictures at speeds different from the recording speed, in connection with which the video signals are stored in a picture memory, the video signals are stored under group addresses in 60-byte blocks, both for the luminance and chrominance signals. After a predetermined storage period has elapsed, the stored data are overwritten with erasing value signals. A circuit arrangement for this operation includes an administrative memory (4) for which the storage duration values for contents stored under every block address is, beginning after writing-in, successively reduced in value. When a zero value is reached, the corresponding block address is stored and used in its turn as a write-in address for the erasing value signals which replace the video data previously written in to the picture memory under this address. The erasing orders are preferably accumulated in a buffer and then executed while no usable signals for storage in the memory are being picked up (i.e. when the tape scanning is passing over boundary areas between adjacent tracks).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.