| 摘要 |
PURPOSE:To improve the noise characteristic by providing a voltage controlled oscillator separately at the outside of a loop of a PLL circuit so as to use the output. CONSTITUTION:A VCO13 is separately provided in addition to the voltage controlled oscillator VCO3 in the PLL circuit, a control voltage of the VCO13 is used as a signal obtained from an output of a loop filter 12 of the PLL circuit through a noise LPF14. Then an oscillating signal of the VCO13 is inputted to a mixer 12 so as to obtain local oscillating signal. |
