| 摘要 |
PURPOSE:To secure the synchronization between the frequency and the phase of the internal oscillator circuit and the external driving signal, by comparing the phase of the external driving signal with the oscillation frequency or the like of the oscillator circuit via the FF circuit and then giving the control to the oscillator circuit with the output signal of the above comparison. CONSTITUTION:Oscillator circuit 10 consists of main oscillator circuit transistor TR1, quartz oscillator 5, frequency control TR2 and others. And the oscillation output is sent to the T input terminal of D-type FF21. At the same time, the external color subcarrier signal is sent to the D input terminal of FF21 from input terminal 14 through capacitor 31 and inverter 22, and the oscillation frequency or its divided frequency is compared with the phase of the external signal at FF21. And circuit 10 is controlled by the output signal of the above comparison. In addition, the subcarrier signal given from outside is supplied to voltage control circuit 20 to be converted into the DC voltage. And voltage control TR2 is controlled by the output of the DC voltage. Thus the frequency and the phase of the internal oscillator circuit can be synchronized with the external driving signal. |
