| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a modulation circuit system and a voltage controlled oscillator capable of avoiding the performance degradation of the voltage controlled oscillator by reducing a circuit load on the voltage controlled oscillator of a PLL loop. <P>SOLUTION: The system includes the PLL loop having the voltage controlled oscillator 12; an adding means 17 for adding a modulation signal and an adjusting voltage out of the PLL loop; and a frequency coarse-adjusting means 18 for supplying an output from the adding means 17 to the voltage control oscillator 12. Further the system supplies an added signal of the modulation signal added and output from the adding means 17 and the adjusting voltage outside the PLL loop to the voltage controlled oscillator 12 through the frequency coarse-adjusting means 18, and generates a modulation signal by superposing an oscillation frequency signal of the voltage controlled oscillator 12 in the PLL loop to the added signal. <P>COPYRIGHT: (C)2008,JPO&INPIT |
