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:
May. 06, 1980
Filed:
Aug. 02, 1978
Yasuichi Ushiyama, Toyko, JP;
Setsuo Yamamoto, Toyko, JP;
Nippon Electric Co., Ltd., Tokyo, JP;
Abstract
In order to stabilize the black level in the red, green or blue channel, black pulses are inserted during a blanking period and are of a level slightly higher than the black level. The resulting color signal is clamped in a first clamping circuit to a predetermined voltage during that part of the blanking period which is free of the black pulse inserted therein, and, after being processed for white compression, black clipping or gamma correction, is provided to a second clamping circuit for fixing the clamping point at a definite and preselected voltage. The black pulse level of the output from the second clamping circuit is compared with a reference voltage and, upon the result obtained, the clamp voltage of the first clamping circuit is controlled to thereby completely suppress black level variations. With this processing amplifier device, the pedestal level is adjustable by varying either the reference voltage or the level of the black pulses.