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:
Mar. 07, 1989
Filed:
Jul. 11, 1988
Hiroshi Suzuki, Monroeville, PA (US);
Koji Osafune, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A recording/reproducing system is provided with a PLL circuit for outputting data pulses and clock pulses on the basis of the read data reproduced from a magnetic recording medium. An external synchronization detection circuit is provided which detects the synchronization data (predetermined zero pattern data), recorded in synchronization areas of the magnetic recording medium, on the basis of the read data. When the synchronization data is detected, the synchronization detection circuit enables the PLL circuit to oscillate in synchronism with the read data. An internal synchronization detection circuit is provided, which detects the synchronization data (predetermined zero pattern data), as recorded in the synchronization areas of the magnetic recording medium, on the basis of data pulses derived from the PLL circuit and the clock pulses. A preventing circuit is further provided. When address mark data is not detected within a predetermined period of time after the external synchronization detection circuit detects th synchronization data, the preventing circuit prevents the PLL circuit from oscillating in synchronism with the read data.