| 摘要 |
PURPOSE:To execute the automatic frequency control with a high accuracy even when the band of a single tuning circuit is made narrow and a short burst signal is inputted by providing a sample holding circuit at the output side of the phase detector, removing the essential error voltage only by the static frequency deviation of respective burst signals and executing the automatic frequency control. CONSTITUTION:A sample holding circuit 9 is provided at the output side of the phase detecting device, the part only of an essential error voltage 19 by the frequency deviation of respective burst signals is sampled in accordance with the burst detecting signal from a burst detecting circuit 8 out of the phase error detecting voltage which is the output of a phase detecting device 7 by a sample holding circuit 9. The sampled error voltage 19 is held up to the time of the ne4t sampling. The peak value of the positive voltage of the error voltage 19 sampled to the sample holding circuit 9 is held to a positive voltage peak holding circuit 10, and the peak value of the negative voltage is held at a negative voltage peak holding circuit 11. Thereafter, the automatic frequency control is executed as well as the conventional automatic frequency control circuit. |
