| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage controlled oscillating circuit that outputs a high frequency, where frequency control can be realized, to provide a phase synchronization circuit that makes quality of a clock stable, and to provide an optical disk unit where the reliability of reproduced information of the unit can be enhanced by mounting the digital phase synchronization circuit whose dispersion is suppressed onto the unit. SOLUTION: The digital voltage controlled oscillating circuit is provided with a fixed frequency oscillator 3 that generates a clock with a specific frequency, a phase control circuit 2 that generates a pulse whose phase is deviated by an input phase with respect to an output of the fixed frequency oscillator 3, and a frequency/phase conversion circuit 1 that converts an input frequency into a phase deviation quantity with respect to the specific frequency of the fixed frequency oscillator 3 and controls the phase control circuit 2 on the basis of the converted value.
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