Optical recording and reproducing apparatus for tracking wobbling guide grooves
US5383169A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 1994 |
| Grant date | Jan 17, 1995 |
| Priority date | — |
| Expiry date | Feb 15, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/094
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording and reproducing apparatus uses a laser to form one or more spots on an information recording medium preformatted with wobbling guide grooves, and detects tracking error. If the differential push-pull method of detecting tracking error is used, a center spot is flanked by satellite spots distant by an odd multiple of half time repeating period of tile wobble. If tile three-beam method is used, the distance is an odd multiple of one-fourth the repeating period of the wobble. If the push-pull method is used, a split photodetector generates a pair of electrical signals. The sum and difference of these signals are filtered, then synchronously detected, and the result is combined with the difference signal to generate a corrected tracking error signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.