Focus control through detection of the rate of error in discs with a control signal inversely dependent on the error rate
US4809253A · kind A · utility
11Cited by
7References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1986 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Sep 22, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0908
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A focus controller for a player for rotating optically scanned information-based disks has an optical scanner with a focus actuator driven by a transformer. The loop amplification of the control circuit is controlled in accordance with a control signal that varies inversely as a function of the type and frequency of the disk errors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.