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:
Sep. 09, 1980
Filed:
Nov. 21, 1978
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
360 67 ; 360 63 ;
Abstract
The difference between the two gain control signals for two amplifiers which correspond to two of a plurality of read heads which have the maximum and minimum output levels is detected. Whether or not the difference exceeds a predetermined value indicates an abnormality of the outputs of the read heads due to dust adhering thereto.