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:
May. 30, 1995
Filed:
Apr. 22, 1994
Akira Matsueda, Tokyo, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
An optical data reproducing apparatus detects a moving speed of an optical card and correct reproduced data in accordance with the detected speed in order to compensate for a speed variation of the optical card, Two read beams which are separated by a given distance in a track direction are irradiated to the card and are detected by two detectors, The moving speed is detected based on a difference between detection timings of the two detectors with regard to a given pit. In order to make pit-to-pit correspondence between the detection timings of the two detectors, a sync portion is first detected and the last pit in the sync portion is numbered the first pit and the difference between the detection timings of the same ordered pits is calculated to obtain the moving speed, The sync portion is recorded as a plurality of pits arranged at regular intervals, Intervals of the pits are detected and a ratio of the intervals detected is compared with a predetermined ratio for representing a sync pattern.