Method and apparatus for calibrating focus and tracking error signals in an optical drive with measuring offsets during track jumps
US5504726A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 1994 |
| Grant date | Apr 2, 1996 |
| Priority date | — |
| Expiry date | Apr 6, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/094
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention makes possible the calibration of the tracking error signal and the focus error signal repeatedly when an optical disk drive is in the normal operation mode. Errors (offset and amplitude error) of the focus error signal and the tracking error signal are detected during at least three track jumps by making use of a track jump performed once per rotation of disk in the track following mode. An offset value of the focus error signal is calculated based on the amplitude of a tracking error signal generated during at least two track jumps by adding a positive or negative offset to the original target value of the focus error signal, and values of offset and amplitude error of the tracking error signal are calculated based on a maximum value and a minimum value of a tracking error signal generated during at least one track jump without modifying the original target value of the focus error signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.