| 摘要 |
PURPOSE:To rapidly respond to the fluctuation of a DC component, by forming a phase compensation voltage by comparing the phase of a reproduced synchronizing signal with that of a reference horizontal synchronizing signal and applying a differential processing with a compared result before one revolution of a disk. CONSTITUTION:A reproduced horizontal synchronizing signal is separated from a reproduced output from the disk via a variable delay element 28 at a synchronizing separator circuit 31, and the phase difference of the signal and the reference horizontal synchronizing signal is detected at a phase comparator 22, and is held at a sample/hold circuit 24 at every revolution of the disk. A phase compared result prior to one revolution of the disk and a present phase compared result are processed at a differential circuit 25 and a phase compensation circuit 26, and a voltage from which the DC component is removed and responded to time base fluctuation due to the eccentricity of the disk is generated. The variable delay element is controlled by a VCO27 to which the voltage is supplied, and the phase of the reproduced output is corrected also as responding rapidly to the fluctuation of the DC component.
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