Method and apparatus for erasing a signal recorded on a magnetic disk
US4714969A · kind A · utility
3Cited by
3References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1985 |
| Grant date | Dec 22, 1987 |
| Priority date | — |
| Expiry date | Sep 16, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/024
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video signal recorded on a magnetic disk is erased by applying a fixed frequency erasing signal as the disk is decelerating. By recording the erasing signal while slowing the disk, an effect is obtained that is comparable to scanning through a range of increasing frequencies. The high frequencies obtained, which are ordinarily beyond the frequency response of the erasing circuit, are effective in removing the resident video signal and in preparing the disk for a new recording.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.