| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase locked loop that is configured to be in operation according to a plurality of characteristics flexibly with high reliability over a sufficiently wide frequency range. SOLUTION: The phase locked loop includes an input comparator 2 that generates a deviation signal, and the deviation signal is used to drive an oscillator 5 to generate an output signal (CLKOUT) locked to an input signal. The oscillator 5 is operated according to a plurality of characteristics under the control of a control means 8 including a search means. The search means executes a 1st search stage for a characteristic group where an operation of the oscillator 5 is allowed by scanning the range that can gradually be reduced according to a general binary search procedure. When the 1st search step is finished, other fine search means identifies an optimum operating point to automatically compensate the fluctuation that may be possible. |
