Recording or playback device for optical information carriers having a servo control circuit and method for treating error signals in such a device
US6046967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 2, 1997 |
| Grant date | Apr 4, 2000 |
| Priority date | — |
| Expiry date | Oct 2, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0948
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Recording or playback devices for optical recording carriers have a servo control circuit which controls the tracking and the focus of an optical scanning unit 1 with reference to an error signal. According to the invention, the error signal is non-linearly amplified upstream of the servo controller, in order to process strong external mechanical effects, normally referred to as shocks, in such a way that the tracking and the focus are retained or adjusted. If there is a defect, such as a scratch on the disc etc., a defect detector and a linear amplifier connected in parallel with the non-linear amplifier are additionally used, the linearly amplified or non-linearly amplified error signal being fed to the servo controller as a function of the output signal of the defect detector. The sign of the error signal, which includes direction information, is retained in the case of the non-linearly amplified error signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.