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:
Aug. 01, 1989
Filed:
Oct. 20, 1987
Applicant:
Inventors:
Masahiro Takasago, Odawara, JP;
Shinichi Arai, Odawara, JP;
Assignee:
Hitachi, Ltd., Chiyoda, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 32 ; 369 54 ; 369 58 ; 360 25 ; 360 29 ;
Abstract
An optical disk is provided with a dedicated track area for recording optical conditions for read and write operations. The apparatus includes different types of demodulating circuits for allowing any type of demodulation to be adopted. After parameters, recorded on the dedicatad track area through phase encoding demodulation, are read out, the demodulating circuit compatible with the modulation type adopted in recording the data is selected for demodulation of the data.