Servo circuit for generating a tracking error signal for optical disk player
US4860271A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1988 |
| Grant date | Aug 22, 1989 |
| Priority date | — |
| Expiry date | Mar 11, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/106
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A servo circuit for use in an optical disk player or the like, which can track a disk having a large eccentrically without abnormal sampling of the RF signal produced as a result of scanning the disk. The servo circuit according to this invention comprises a first comparator for comparing RF signals from a pair wobbled pits on a optical disk and generating a difference signal indicating the level difference between the AF signals; a holding means for holding the difference signal for a predetermined period; a reference level producing circuit for setting reference levels having a predetermined width with the level of a previously sampled difference signal of the holding means as a center; a second comparator for comparing the level of a presently sampled difference signal of the first comparator with the reference level and outputting a first signal indicative of the comparative result; and a selector for selecting and outputting, as a tracking error signal, either the presently sampled difference signal and a second signal having a level within the predetermined width of the reference level in accordance with the comparative result. The presently sampled difference signal is selec…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.