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:
Apr. 16, 1991
Filed:
Jul. 14, 1988
Mamoru Horino, Hamamatsu, JP;
Yamaha Corporation, Hamamatsu, JP;
Abstract
A rotation control device for a rotary head in a rotary head type magnetic recording and reproducing device such as an R-DAT cmprises a rotary head including an FG (frequency generator) for producing a signal at a period determined by equally dividing one rotation of a drum and a PG (phase generator) for detecting a rotation reference position of the drum, a circuit for generating a PG reference signal as a reference signal for a PG detection signal provided by the PG, a circuit for generating an FG reference signal as a reference signal for an FG detection signal provided by the FG, and a control circuit for controlling rotation phase of the drum to a predetermined state by controlling rotation of the drum in accordance with a phase error between the PG detection signal and the PG reference signal and a phase error between the FG detection signal and the FG reference signal. Rotation of the drum is controlled in accordance with the two phase errors in such a manner that the PG detection signal is locked with the PG reference signal at a predetermined phase difference and the FG detection signal is locked with the FG reference signal at a predetermined phase difference whereby the phase of rotation of the drum is controlled to a predetermined state.