| 摘要 |
PURPOSE:To automatically set a frequency division ratio according to the settings of a multiplication magnification and an input frequency range by providing a magnification setting device, an input frequency setting device and a code converter, and to make an operation easy. CONSTITUTION:When an external signal of a frequency Fin is inputted in a terminal 10, the external input signal and the signal from a frequency divider 18 where M frequency division is performed for a multiplication output signal Fout are compared in a frequency comparator 12. The comparator 12 controls the oscillation frequency of a VCO 14 so that the input frequency Fin and the signal frequency Fout/M from the frequency divider 18 may be equal. The magnification M of a multiplier is determined by determining the frequency division ratio M of the frequency divider 18 by a magnification setting device 20 by an operator. The operator inputs the frequency range of a multiplication input signal in an input frequency setting device 42. A code converter 40 sets the frequency division ratio N to be determined by the magnification setting and the input frequency setting. |
