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:
Feb. 10, 1998
Filed:
Dec. 22, 1994
Isao Kimura, Tokyo, JP;
Naoto Inaba, Hiratuka, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An information recording and playback device for use with disk-type medium formatted in a ZCAV format. Sector marks are written on the disk-type recording medium and differ in frequency according to the zone to which the sector belongs. Where frequencies in adjacent zones are close, sectors in adjacent zones can be written with different polarities or sizes. The information recording and playback device is provided with a number of sector mark detection circuits, which number the same or less than the number of zones formed on the recording surface of the disk. Each sector mark detection circuit is set to correspond to one zone, and output a signal when the pattern of the sector marks of the zone to which that sector mark detection circuit corresponds can be detected. When the sector mark is detected by one of these sector mark detection circuits, the actual position of the head is determined. Then, the frequency of a reference clock signal is switched to a clock signal which has a frequency equal to the recording frequency which corresponds to zone where the head is located. Where the number of sector mark detection circuits is less than the number of zones, the sector mark detection circuits are configured so that they can detect the patterns of the sector marks of all zones by changing the settings to match the target zone containing the target sector and as many adjacent zones as can be covered by the other sector mark detection circuits.