| 摘要 |
PURPOSE:To generate an arbitrary dot clock frequency only by adjusting a control voltage by composing a VCO from a NAND circuit(NOR circuit), a coil, a capacitor, and a voltage variable capacitance diode(VCD), and varying the control voltage to be applied on the VCD. CONSTITUTION:The terminal on one side of a resistor 2 is connected to the output of the NAND circuit 1 of two gates, and following that, the terminal on one side of the coil 3 and the terminal on one side of the capacitor 4 are connected to the terminal on the other side of the resistor 2, respectively. The terminal on one side of the VCD 6 and the output side of a voltage level shift circuit 7 are connected to the terminal on the other side of the capacitor 5, respectively, and the terminal on the other side of the VCD 6 is grounded. When a horizontal synchronizing signal goes to H and oscillation standby time elapses, oscillation is started. The output of the voltage level shift circuit 7 changes by varying the control voltage 8, and by changing the capacitance of the VCD 6 by the above change, the frequency of an output signal 10 i.e., the dot clock frequency can be adjusted arbitrarily.
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