| 摘要 |
A VCO, in which its temperature characteristics are good and its high frequency accuracy and high phase accuracy can be realized without making its master clock frequency to operate the VCO high and its circuit can be realized as an LSI, is provided. Further, a PLL circuit using this VCO and a data recording apparatus using this PLL circuit are provided. The VCO provides a digital VCO, a phase modulator, and a frequency band limiting means. The digital VCO outputs an oscillating frequency clock and phase difference being lower than output cycle resolution at the same timing of the output of the oscillating frequency clock. The phase modulator makes side-band components of the output from the digital VCO move from the position near the fundamental frequency to farther bands by modulating the phase of the output from the digital VCO based on the phase difference. The frequency band limiting means such as a BPF eliminates the side-band components moved to the farther bands. With this, a clock whose jitters are low can be obtained.
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