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Patent Searching and Data


Title:
ADAPTIVE CLAMP CIRCUIT FOR GHOST ELIMINATING DEVICE
Document Type and Number:
Japanese Patent JPH0443770
Kind Code:
A
Abstract:

PURPOSE: To obtain a clamp circuit able to correctly recover a DC component of a video signal by providing a means discriminating whether the synchronization is stable or unstable and a means selecting a video signal subject to pedestal clamp with a vertical keyed pedestal clamp circuit when the stable synchronization is discriminated.

CONSTITUTION: A video signal Sin given to an input terminal 1 is divided into two systems via a buffer 14 and an amplifier 17, the one is led to a SYNC tip clamp circuit 11 via a buffer 15 and the other is led to a V keyed pedestal clamp circuit 12 via a buffer 16. When a horizontal synchronizing signal and a vertical synchronizing signal included in a received television signal and a basic clock in a ghost eliminating device are in a prescribed relation the synchronization is discriminated to be stable. Based on the result of discrimination, the video signal pedestal-clamped by the V keyed pedestal clamp circuit 12 is selected and the result is outputted as a video signal after clamping. Thus, the DC component of the video signal is correctly recovered regardless of occurrence of a ghost fault.


Inventors:
KITAMURA KAZUHIRO
Application Number:
JP1990000151350
Publication Date:
February 13, 1992
Filing Date:
June 08, 1990
Export Citation:
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Assignee:
SHARP KK
International Classes:
H04N5/16; H04N5/18; H04N5/21; (IPC1-7): H04N5/16; H04N5/18; H04N5/21