| 摘要 |
PURPOSE:To stabilize the oscillation frequency of a voltage controlled oscillator(VCO) by cancelling a high frequency component included in a phase error signal after passing through a low-pass filter(LPF) and inputting it to the VCO as a control signal being free from a ripple. CONSTITUTION:A high-pass filter(HPF) 3, a phase inverter 4 for inverting the output phase of the HPF 3, and an adder 5 for adding the output signal of a low-pass filter(LPF) 2 and the output signal of the phase inverter 4 and applying them to a voltage control oscillator(VCO) 6 are added to this circuit. In this stage, a phase error signal after passing through the low-pass filter(LPF) 2 is bisected and one of them is extracted as to its high frequency component by the HPF 3, and thereafter, brought to phase decision, and becomes one voltage control oscillator(VCO) 6 by adding it to the other phase error signal. In such a manner, a generated ripple is cancelled, and the oscillation frequency of the VCO 6 can be stabilized. |
