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:
Jun. 29, 1993
Filed:
Jul. 10, 1991
Applicant:
Inventors:
Atsuhisa Kageyama, Ibaraki, JP;
Hideaki Sadamatsu, Hirakata, JP;
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04N / ; H04N / ; H04N / ; H04N / ;
U.S. Cl.
CPC ...
358139 ; 358 39 ; 358168 ; 358172 ; 307494 ;
Abstract
The average picture level (APL) of a video luminance signal is detected, wherein the output of a first current mirror circuit used as the load of a differential amplifying circuit is fed into a smoothing circuit via a second current mirror circuit. The direct current voltage of the output and the detection voltage amplitude may be optionally set without causing an offset voltage in the output average picture level voltage, with the current flowing through the second current mirror circuit being made zero at the time of APL=0%.