| 摘要 |
PURPOSE:To increase the transient response and the frequency stability, by controlling VCO according to the output frequency of the frequency demultiplier and VCO of PLL. CONSTITUTION:The oscillation frequency of VCO 5 of the PLL frequency synthesizer 4 and the frequency corresponding to the frequency dividing ratio of the programmable frequency demultiplier 6 are compared with the circuit 21, and the positive or negative output pulse according to the magnitude of the both frequencies is superimposed on the DC control signal from LPF 9 and is fed to VCO 3, controlling the oscillation frequency. As a result, the time until the oscillation frequency is completely locked can be reduced. |
