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:
Jan. 29, 1991
Filed:
Nov. 29, 1988
Akihiro Ishikawa, Neyagawa, JP;
Haruo Isaka, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical information recording apparatus optically records digital information on a recording medium, for example, a disc, a tape and so on. The area of an optical spot cannot be made smaller than a minimum area determined by a numerical aperture of an objective lens and the wave length of a reproducing beam. Consequently, this causes a problem that the code of digital signals often fails to be discriminated in reproducing short pits and/or short pit-intervals which are recorded on the recording medium. The apparatus detects a phase difference between each edge of an input digital signal and each corresponding edge of a digital signal reproduced from the recording medium. The edges of a next input digital signal of the same code construction as that of the first input signal are corrected by a correction amount according to the above phase difference, and such operations are repeated whenever input digital signals are inputted. Consequently the apparatus can decrease errors of code discrimination to minimum and achieve high edge correction. Furthermore, since the input digital signal is delayed by a time interval between the recording by the recording head and the reproducing by the reproducing head, edge correction can be achieved with high precision.