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. 21, 1984
Filed:
Apr. 15, 1981
Applicant:
Inventors:
Sueki Baba, Osaka, JP;
Tomio Yoshida, Katano, JP;
Nobuo Akahira, Yawata, JP;
Tadaoki Yamashita, Hirakata, JP;
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
369 48 ; 369111 ; 369124 ;
Abstract
An optical signal recording and reproduction or retrieval system which records a primary signal on a recording track provided on a recording medium by projecting a laser beam which has been modulated by the primary signal onto the recording track, and further records a secondary signal, by superposition, on the recording track by projecting the laser beam which has been modulated by the secondary signal having a frequency band which is different from that of the primary signal onto the recording track for enabling the deleting of the previously recorded primary signal.