| 摘要 |
PURPOSE:To compensate the phase fluctuation of a subcarrier due to an external cause, such as a peripheral temperature, etc., by locking a subcarrier signal with an external input using a color burst signal obtained from the output of an encoder circuit. CONSTITUTION:The color burst signal taken out from the external input with a burst separation part 6 is phase-compared with the color burst signal taken out similarly from the output of an encoder circuit 11 with a burst separation part 12 at a phase comparator 7. The output of the phase comparator 7 controls a voltage controlled oscillator 9 through a low-pass filter 8, and thereby, the subcarrier signal that is the output of the voltage controlled oscillator 9 is phase-locked against the external input. At such a time, due to the fact that a signal compared with the external input is the burst signal from which the output of the encoder 11 can be obtained, the phase fluctuation of the signal is corrected automatically with a PLL even when the phase of the subcarrier is fluctuated by the change of the peripheral temperature, etc.
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