| 摘要 |
PURPOSE:To obtain a system with short pull-in time by attaching a reset function on a frequency divider comprising the system. CONSTITUTION:A control voltage Vf in accordance with a desired frequency is added by a frequency change instruction, and simultaneously, two frequency dividers 11, 12 are reset. In such a case, since fr is outputted to the frequency divider 11 after 1/reference frequency (fr) seconds, and an output frequency (f0)/N is outputted almost simultaneously, it is enough to feed back the phase difference of fr and f0/N to a VCO 13. Since the reset function is attached on the frequency dividers 11, 12 comprising the system, a frequency synthesizer with fast pull-in speed can be comprised. |
