| 摘要 |
PROBLEM TO BE SOLVED: To provide a PLL circuit, which can output oscillated signals having less spurious signals by moving a spurious generating frequency to the outside of the passing band of a loop filter. SOLUTION: When a frequency-dividing ratio K is changed at dividing of the frequency of the output signal of a VCO 11 by means of a variable frequency divider 22, the output signal of the divider 22 is changed. Namely the frequency of the input signal of a DDS 13 changes. When the frequency of the input signal of the DDS 13 changes, a spurious signal generating frequency also changes, because the frequency dividing ratio N/M of the DDS 13 changes. |
