Tracking system with dual differential signals with fraction of A/C signal added back to D/C signal
US7385888B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 2003 |
| Grant date | Jun 10, 2008 |
| Priority date | — |
| Expiry date | Apr 6, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/095
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Tracking system for guiding an optical beam on tracks on an optical disc, said tracking system comprising a photodetector (A1, A2) for detecting optical beams derived from said optical beam, said photodetector generating a first output signal (A) and a second output signal (B), said tracking system comprising first processing means for generating a first differential signal (PP(DC)) corresponding to the low-frequency part of a difference between said first and second output signals. The tracking system comprises second processing means for generating a tracking error signal (PP(AC/DC)) defined by the addition of said first differential signal (PP(DC)) to a second differential signal (PP′(AC)), said second differential signal corresponding to a fraction of the difference in amplitude of the high-frequency components of said first and second output signals. Use: Optical disc player/writer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.