| 摘要 |
PURPOSE: An apparatus and method of automatically controlling a gain of a digital TV are provided to detect a property difference in each channel or a signal strength in a same channel, thereby automatically varying an AGC(automatic gain control) property. CONSTITUTION: The apparatus for automatically controlling a gain of a digital TV comprises a broadcasting signal receiving portion for frequency-converting and filtering a received digital broadcasting signal to output an intermediate frequency signal, an automatic gain controlling portion for amplifying and detecting the intermediate frequency signal output from the broadcasting signal receiving portion to output a baseband signal, a voltage level detecting portion for converting the baseband signal in to a digital signal to detect a corresponding voltage level, an AGC adjusting portion(430) for adjusting an amplification rate of the automatic gain controlling portion by a delay voltage applied from an outside and an output of the voltage level detecting portion to output a high frequency AGC voltage value, a signal treating portion for treating a signal so that the high frequency AGC voltage value output from the AGC adjusting portion is output through a control signal line, a micro-computer(700) for comparing an output from the signal treating portion with a predetermined reference value to control a voltage level of the delay voltage applied to the AGC adjusting portion, and a voltage level controlling portion for generating the delay voltage according to a control of the micro-computer and outputting the delay voltage to the AGC adjusting portion.
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