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. 19, 1978
Filed:
Aug. 15, 1977
Applicant:
Inventor:
Mitsuharu Akatsu, Yokohama, JP;
Assignee:
Hitachi, Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04N / ;
U.S. Cl.
CPC ...
358174 ;
Abstract
A signal having a maximum amplitude corresponding to a pedestal level of a composite video signal is produced by removing a horizontal synchronizing signal from the composite video signal. An automatic gain control signal is derived from the first mentioned signal in dependence of the peak value thereof to control a high frequency amplifier and or an intermediate frequency amplifier so that the pedestal portion at the maximum amplitude level of the composite video signal is maintained constant. In this way, a stabilized pedestal portion or the black level can be attained, which in turn results in a stabilized contrast.