APPARATUS FOR STABILIZING BRIGHTNESS AUTOMATICALLY IN A VIDEO DISPLAY APPARATUS TO PREVENT AN ABS SIGNAL FROM BEING AFFECTED BY A SPEED MODULATION SIGNAL AND A DYNAMIC FOCUS SIGNAL

摘要

PURPOSE: An apparatus for stabilizing brightness automatically in a video display apparatus is provided to prevent an ABS(Automatic Brightness Stabilization) signal from being affected by a speed modulation signal and a dynamic focus signal by canceling them during the period of time for detecting a pulse signal which is inserted into a video signal for the sake of an ABS operation. CONSTITUTION: A video signal process part(102) inserts a predetermined pulse signal into a vertical retrace interval of a video signal and then applies it to an electron gun of a CRT(Cathode Ray Tube). An ABS signal detection part(106) detects the pulse signal affected by the electron gun. A speed modulation part(108) generates a speed modulation signal for stressing a brightness component of the video signal and applies the speed modulation signal to speed modulation coil of the CRT. A retrace canceling part(202) generates a canceling signal for canceling the speed modulation signal from the vertical retrace interval.