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:
Jul. 14, 1987
Filed:
Jul. 25, 1984
Toshio Murakami, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A signal processing circuit for a color video camera using a single image pickup tube with less color phase and color noise at a low luminance portion, comprises in a clamping circuit for clamping a black level of a video signal produced from the image pickup element, a circuit for superimposing a shading correction signal onto a clamp reference signal. To further reduce the color phase and noise, there is provided a circuit for separating a luminance signal and a plurality of chrominance signals from a video signal produced from the image pickup tube, a circuit for demodulating the separated chrominance signals to obtain color difference signals with the luminance signal, a circuit for modulating a carrier with the color difference signals to obtain carrier color difference signals, a variable gain amplifier circuit provided in a transmitting path of the carrier color difference signals, and a circuit for detecting a luminance component of a level lower than a predetermined level from a luminance signal of a video signal produced from the image pickup tube, whereby the variable gain amplifier circuit operates such that when the level of the luminance signal is lower than a predetermined level, the amplitude of the carrier chrominance signal is made smaller as the luminance becomes lower.