| 摘要 |
A video decoder removes noise caused by a luminance signal component when separating a chrominance signal from a composite video baseband signal. The video decoder includes a first signal generator multiplying the composite video baseband signal by a cosine component having a predetermined frequency and low-pass-filtering the multiplied signal to generate a first signal, a second signal generator multiplying the composite video baseband signal by a sine component having the predetermined frequency and low-pass-filtering the multiplied signal to generate a second signal, a third signal generator differentiating the first and second signals and performing a predetermined operation on the differentiated signals to generate a third signal having a value corresponding to a frequency band in which the chrominance signal exists, an operating unit receiving the third signal and performing a predetermined operation on the third signal to output the chrominance signal, a fourth signal generator performing a predetermined operation on the first and second signals to generate a fourth signal having a value corresponding to the amplitude of the chrominance signal, and a noise removal unit receiving the chrominance signal, the third signal and the fourth signal and correcting the chrominance signal in response to the third and fourth signals to remove luminance component noise included in the chrominance signal.
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