Circuit for remote-scanning audio or video disk player for contactless scanning with coarse and fine drive mechanisms for radial servo readjustment
US4794579A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 4, 1986 |
| Grant date | Dec 27, 1988 |
| Priority date | — |
| Expiry date | Nov 4, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0953
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In order to obtain perfect scanning of audio and/or video disks through application of contactless scanning with a coarse and fine drive system for radial servo readjustment, the fine drive optimum working point is reached through a correct interaction of coarse and fine drive, even in the case of different large radial eccentricity amplitudes. This is achieved through adjustment of the coarse drive, using a comparator, as a threshold value detector, and through an evaluation of the pulse sequences occurring at the comparator output. A radial-error signal for the coarse drive is obtained from a control parameter for the fine drive. The coarse drive is started by pulses when the pulses obtained from a radial-error signal exceed a predetermined pulse-to-interval ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.