초록 ▼

A color subcarrier reproducing circuit reproduces a color subcarrier on the basis of a color burst signal in a color television signal in which phase reference data synchronized with the color burst signal is inserted in a predetermined position in a vertical blanking period, and provides a first cl

A color subcarrier reproducing circuit reproduces a color subcarrier on the basis of a color burst signal in a color television signal in which phase reference data synchronized with the color burst signal is inserted in a predetermined position in a vertical blanking period, and provides a first clock signal whose frequency is equal to the frequency of the color subcarrier and a second clock signal whose frequency is four times the subcarrier frequency. The second clock signal is frequency-divided by first and second frequency dividers to produce a reproduced horizontal sync signal, and frequency-divided by first and third frequency dividers to produce a reproduced vertical sync signal. A phase reference data reproducing circuit reproduces the phase reference data from the color television signal using the first clock signal as a sampling signal. On detecting that the phase reference data reproduced by the phase reference data reproducing circuit has a predetermined pattern, a pattern detecting circuit resets the first to third frequency dividers, thereby keeping the phases of the horizontal and vertical sync signals in sync with the phase reference data.

대표청구항 ▼

A sync-signal reproducing circuit for obtaining sync signals from a color television signal, said sync-signal reproducing circuit comprising: receiving means for receiving the color television signal, the color television signal containing phase reference data synchronized with a color burst signal

A sync-signal reproducing circuit for obtaining sync signals from a color television signal, said sync-signal reproducing circuit comprising: receiving means for receiving the color television signal, the color television signal containing phase reference data synchronized with a color burst signal in a predetermined position in a vertical blanking interval, the phase reference data being digital data having a predetermined pattern; color subcarrier reproducing means for reproducing a color subcarrier in accordance with the color burst signal in the color television signal received at said receiving means and outputting a reproduced signal; sync signal generating means, responsive to the reproduced signal output from said color subcarrier reproducing means, for generating sync signals; phase reference data reproducing means, responsive to the color television signal received at said receiving means and the reproduced signal output from said color subcarrier reproducing means, for reproducing the phase reference data from the color television signal and outputting a reproduced phase reference data; and pattern detector means, responsive to the reproduced reference data output from said reference data reproducing means, for controlling said sync signal generating means to keep the phases of the sync signals output from said sync signal generating means in sync with the reproduced phase reference data when a pattern of the reproduced phase reference data output from said reference data reproducing means has the predetermined pattern, wherein said sync signal generating means include: first frequency dividing means for dividing the frequency of the reproduced signal output from said color subcarrier reproducing means to generate a horizontal sync signal; and second frequency dividing means for dividing the frequency of the reproduced signal output from said color subcarrier reproducing means to generate a vertical sync signal, and wherein said pattern detector means includes reset signal generating means, responsive to the reproduced phase reference data output from said phase reference data reproducing means, for generating a reset signal adapted to reset said first and second frequency dividing means.