Auto-master pedestal control circuit

DETAILED DESCRIPTION It is an object of the present invention to provide an auto-master pedestal control circuit which can always give not only a distinct screen but also convenience to the user with a pedestal level of a video signal automatically controlled in accordance with each scene using a microcomputer and a pedestal detector.
The present invention can be achieved in a way that an applied video signal is processed to be changed to an uniform direct current (DC) signal through the master pedestal detector and that the pedestal level of the video signal offered as an output of the microcomputer is controlled automatically.
The above object may be effected by providing an auto-master pedestal control circuit comprising: detecting means including an inverting amplification means, a clamping means and a integration means for detecting a NAM video signal or luminance video signal.
a logic operation means connected to the detecting means and comparing a detected pedestal level with an inner reference level; an amplification means for amplifying an inputted video signal; and a master pedestal controlling means for controlling a gain provided by an output of the logic operation means and an output of the amplification means.