Title:
PICTURE QUALITY COMPENSATING DEVICE
Document Type and Number:
Japanese Patent JPS63164764
Kind Code:
A
Abstract:
PURPOSE:To always automatically obtain proper picture quality by extracting the signal component of prescrived frequency band of a video signal, forming a contour signal with an always constant amplitude from the extracted signal, i.e., the contour signal by means of the gain control using a feedback loop so as to use it as a scanning speed modulation signal. CONSTITUTION:An amplitude detection circuit 22 detects the amplitude of a primary differentiation signal from a gain control circuit 17, consists of, e.g., a peak detection circuit or the like and outputs a detection signal corresponding to the amplitude of the primary differentiation signal. A comparator 23 compares a detection signal with a reference potential E0, the resulting comparison signal controls the gain control circuit 17 so as to always output the primary differentiation signal with a constant amplitude V2 from the gain control circuit 17. The primary differentiation signal with a constant amplitude in this way is used to apply the scanning speed modulation so as to reduce the blooming of a CRT 8 at high brightness and high definition display and to obtain always proper picture quality with respect to various video signals.
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Inventors:
TSUJIHARA SUSUMU
Application Number:
JP31225786A
Publication Date:
July 08, 1988
Filing Date:
December 26, 1986
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H04N5/208; H04N3/32; (IPC1-7): H04N3/32; H04N5/208
Attorney, Agent or Firm:
Toshio Nakao