Motor rotation control apparatus with motor rotational frequency memory
US4959733A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1988 |
| Grant date | Sep 25, 1990 |
| Priority date | — |
| Expiry date | May 16, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/28
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for controlling the rotation of a motor to rotate a recording medium where an information signal and synchronizing signal are recorded. In such motor rotation control, normally the synchronizing signal reproduced from the recording medium is phase-compared with a reference synchronizing signal, and the motor rotation is so controlled as to eliminate the phase error between the two compared signals. And upon occurrence of any great variation in the motor rotation due to information dropout or the like on the recording medium, such variation is detected, and a rotational frequency signal obtained from a rotational frequency detector is phase-compared with a reference frequency signal generated on the basis of the data relative to the motor rotational frequency stored sequentially in a memory. Then the control mode is switched for controlling the motor rotation in such a manner as to eliminate the phase error between the two compared signals, whereby the problems including runaway of the motor and so forth can be solved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.