CLAMP CIRCUIT OF CLAMPING STABLE COLOR SIGNAL OF VIDEO DECODER AND CLAMPING LEVEL CONTROL METHOD THEREOF

摘要

PURPOSE: A clamp circuit of clamping stable color signal of a video decoder and a clamping level control method of the circuit are provided to control a clamping level only when a color signal deviates from a predetermined section to improve picture quality of the video decoder. CONSTITUTION: A color signal clamping circuit for a video decoder includes a clamping unit(21), an analog/digital converter(23), and a clamping controller(30). The clamping unit controls a DC voltage level of a color signal in response to a clamping control signal. The analog/digital converter converts the color signal output from the clamping unit into a digital color signal. The clamping controller generates the clamping control signal to the clamping unit to control the DC voltage level of the color signal in the case that the digital color signal is not included in a predetermined reference section that is constructed by combining a reference signal, the first and second offset values.