Optical recording and reproducing apparatus for tracking wobbling guide grooves
US5303216A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1992 |
| Grant date | Apr 12, 1994 |
| Priority date | — |
| Expiry date | Aug 27, 2012 |
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 the repeating period of the wobble. If the 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.