Video signal processing circuit providing optimum signal level for inverse gamma correction

A video signal processing circuit comprising:

• a gain control amplifier which amplifies each of analog three primary color video signals of red, green, and blue indicative of video information by a predetermined gain and in which said gain is controlled by a gain control signal;
• analog/digital converters for converting said analog three primary color video signals which are generated from said gain control amplifier into digital signals, respectively;
• inverse gamma correcting circuits for effecting an inverse gamma correction to said three primary color digital video signals, respectively;
• a peak level detecting circuit for detecting a peak level of each of the analog three primary color video signals which are supplied to said analog/digital converters;
• and
• a gain control signal generator for generating said gain control signal in accordance with said detected peak levels,
• wherein when at least one of said peak levels is equal to or larger than a predetermined value, said gain control signal generator generates the gain control signal to control said gain control amplifier so as to set a level of each of the three primary color digital video signals which are generated from said analog/digital converters to a peak value.

A video signal processing circuit comprising:

• a matrix circuit to which an analog luminance signal and first and second analog color difference signals indicative of video information are supplied and which generates analog three primary color video signals of red, green and blue;
• analog/digital converters for converting said analog three primary color video signals into digital signals, respectively;
• inverse gamma correcting circuits for effecting an inverse gamma correction to said three primary color digital video signals, respectively;
• a peak level detecting circuit for detecting a peak level of each of said analog three primary color video signals;
• and
• a level control circuit for controlling a signal level of said analog luminance signal in accordance with said detected peak levels,
• wherein when at least one of said peak levels is equal to or larger than a predetermined value, said level control circuit performs a control operation to set a level of each of the three primary color digital video signals which are generated from said analog/digital converters to a peak value.