The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 25, 1990
Filed:
May. 16, 1988
Yoshio Miura, Yokohama, JP;
Motoyuki Suzuki, Yokohama, JP;
Akio Fukushima, Yokohama, JP;
Yonemitu Mori, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
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.