Patent ID: 6246440
Filing Date: 2001-06-12
Classification: H04N

Abstract:
A circuit for generating a reference signal synchronized with a burst signal that is input into the circuit, the circuit comprising:a first and a second voltage-controlled oscillators having a control terminal, respectively, with oscillation frequencies being variable in response to signals supplied to the control terminals;a first frequency divider for dividing a frequency of an output signal of the first voltage-controlled oscillator by j;a second frequency divider for dividing a frequency of an output signal of the second voltage-controlled oscillator by k;a first phase comparator for comparing a phase of an output signal of the first frequency divider with a phase of an output signal of the second frequency divider;a first lowpass filter for smoothing an output signal of the first phase comparator and supplying the smoothed signal to the control terminal of the second voltage-controlled oscillator so as to form a feedback control path;a second phase comparator for comparing a phase of an output signal of the second voltage-controlled oscillator with a phase of the burst signal; anda second lowpass filter for smoothing an output signal of the second phase comparator and supplying the smoothed signal to a control terminal of the first voltage-controlled oscillator so as to form a feedback control path;wherein the reference signal is obtained from the output signal of the second voltage-controlled oscillator.