Adc system, video decoder and related method for decoding composite video signal utilizing clock synchronized to subcarrier of composite video signal

A method for converting a composite video signal into a digital signal according to a synchronized clock, comprising:

• converting the composite video signal into the digital signal according to the synchronized clock, the synchronized clock being synchronized to a frequency and a phase of a color burst of chrominance signals of the composite video signal;
• estimating the phase of the color burst carried on the composite video signal;
• and
• generating the synchronized clock according to the phase of the color burst.

A video decoder for decoding a composite video signal to output a luminance signal and chrominance signals, comprising:

• an analog-to-digital converter (ADC), for receiving the composite video signal and generating the digital signal according to the synchronized clock, the synchronized clock being synchronized to a frequency and a phase of a color burst of chrominance signals of the composite video signal;
• a color burst phase estimator, coupled to the ADC, for estimating the phase of the color burst carried on the composite video signal;
• a phase-locked loop (PLL), coupled to the color burst phase estimator, for generating the synchronized clock according to the phase of the color burst estimated by the color burst phase estimator;
• a luminance/chrominance separator, coupled to the ADC, for generating a pre-luminance signal and a pre-chrominance signal according to the digital signal;
• a U/V demodulator, coupled to the luminance/chrominance separator, for demodulating the pre-chrominance signal to generate a first pre-chrominance signal and a second pre-chrominance signal;
• an interpolation phase generator, coupled to the ADC, for generating an interpolation phase utilized to scale the pre-luminance signal, the first pre-chrominance signal and the second pre-chrominance signal according to a plurality of horizontal synchronization tips of the composite video signal;
• and
• a digital interpolator, coupled to the luminance/chrominance separator, the U/V demodulator and the interpolation phase generator, for scaling the pre-luminance signal, the first pre-chrominance signal and the second pre-chrominance signal to generate the luminance signal, the first chrominance signal and the second chrominance signal according to the interpolation phase.