Electronic offset compensation of the continuous composite track error signal in optical recording
US5197058A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1991 |
| Grant date | Mar 23, 1993 |
| Priority date | — |
| Expiry date | Mar 5, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/094
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
When doing multitrack seek or a single track jump, the midpoint between the maximum and the minimum of a tracking error signal is determined. A peak detector detects the positive peak and the negative peak. These maximum and minimum values are stored in a sample and hold circuit. A summing circuit determines the midpoint between the maximum and the minimum of the tracking error signal. An operational amplifier provides a true error signal to the servo control system that provides the appropriate servo operating point. The invention is based on the fact that even though there is no absolute reference signal indicating the appropriate on-track position, the tracking servo system obtains the track error over the whole range of positions relative to track center when doing a multitrack seek or a single track jump. The appropriate servo operating point is the midpoint between the maximum and the minimum of the track error signal. This provides compensation for level shifts due to factors such as beam displacement, or detector mispositioning, changes in read/write beam profile, and disk tilt. The present invention solves the key disadvantage of the continuous groove tracking method by el…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.