| 摘要 |
A phase locked loop circuit includes a voltage controlled oscillator having an oscillating characteristic value changed by a switching signal. A characteristic controller supplies the switching signal to the voltage controlled oscillator to increase the oscillating characteristic value according to elapse of time. The voltage controlled oscillator oscillates according to both of the oscillating characteristic value and a frequency control signal. Even if the frequency control signal is equal to a power source level at the beginning of supplying electric power, the phase locked loop can be locked in a target frequency.
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