KR970078519A - Gain control device of luminance signal - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically adjusting the gain of a luminance signal. In the related art, a contrast ratio is deteriorated due to a change in gain or an RF modulation depending on an external input or a broadcasting station. The present invention is to solve the above-mentioned drawbacks, and detects the level of the luminance signal input from a broadcasting station or an external device and adds a certain level to a portion detected to be higher than the intermediate level or higher than the maximum value. The present invention provides a device for automatically adjusting gain of a luminance signal, which can be subtracted to reduce a gain difference of an input luminance signal.

Description

Gain control device of luminance signal

Since this is an open matter, no full text was included.

1 is a circuit diagram according to an embodiment of the invention.

Claims (3)

A luminance signal level adjusting device comprising a clamp and an analog / digital converter for clamping an input luminance signal (Y) to maintain a constant level and converting the input luminance signal (Y) into a digital signal, the luminance signal output from the clamp and the analog / digital converter. An intermediate level detector for detecting an intermediate level value of (Y); A correction value calculator for comparing the intermediate level value detected by the intermediate level detector with a reference intermediate level value of the luminance signal and calculating a difference between them; A 1H memory unit which stores a 1H luminance signal among the luminance signals outputted from the clamp and the analog / digital converter; A line delay unit for delaying the luminance signal output from the 1H memory unit by a predetermined time and outputting the delayed signal; A gain controller which adds or subtracts a correction value output from the correction value calculator to a luminance signal output from the line delay unit; A maximum value and an intermediate level value comparison unit configured to output a switching signal of a “high / low” level in comparison with the maximum value of the luminance signal output from the 1H memory unit and a reference intermediate level; And a switching IC configured to select an output of the gain control unit and an output of the luminance signal of the line delay unit by "on / off" operation by the switching signal output from the maximum value and the intermediate level value comparing unit. Signal gain auto adjuster. The display device of claim 1, wherein the correction value calculating unit corresponds to a processing value Va of the intermediate level value and the reference intermediate level value of the luminance signal when the maximum value of the luminance signal is greater than the reference intermediate level value and less than the reference maximum value. When the correction value is applied to the gain adjusting unit, and the maximum value of the luminance signal is larger than the reference maximum value, the gain adjusting unit applies a correction value corresponding to the difference value (-2Va) between the intermediate level value of the luminance signal and the reference intermediate level value. Apparatus for adjusting the luminance signal gain, characterized in that the application is made to. The switching method of claim 1, wherein the maximum value and the intermediate level value comparison unit compare the maximum value of the input luminance signal with a reference intermediate level value when the maximum value of the luminance signal is smaller than the reference intermediate level value. And outputting a signal and outputting a switching signal of a "high" level if the maximum value of the input luminance signal is larger than a reference intermediate level value. ※ Note: The disclosure is based on the initial application.