Patent ID: 6839092

Claim:
A video decoder comprising: a horizontal phased locked loop including a horizontal discrete time oscillator, a color phased locked loop including a color discrete time oscillator generating a color local oscillator frequency f sc , a comparator for comparing the color local oscillator frequency to a color burst to detect any error and a processing means to produce an color PLL nominal increment to the color discrete time oscillator, means for clocking the horizontal discrete time oscillator by a constant frequency, based on a crystal oscillator frequency f crystal , from a ring oscillator f ring where f ring =m*f crystal and f crystal =n*f sc , where m is a predetermined value for setting the frequency of the ring oscillator as a multiple of the crystal oscillator frequency and n is a predetermined value for setting the crystal oscillator frequency from the color local oscillator frequency, means for determining the horizontal phase error Δh from the horizontal sync input and generating an increment inc h to the horizontal discrete time oscillator to maintain lock to the horizontal sync input, means for generating a scaled factor of phase error from the horizontal discrete time oscillator to maintain constant color local oscillator frequency without a division operation, means for adding said scaled factor of phase error to said color PLL nominal increment and feed forwarding to the color discrete time oscillator to maintain constant color local oscillator frequency.