| 摘要 |
<P>PROBLEM TO BE SOLVED: To increase frequency of a high-frequency signal which is superimposed on a drive signal for driving a laser source, in an reproduction operation for measuring amplitude information of an RF signal. <P>SOLUTION: A high-frequency signal is oscillated and outputted from a VCO4 and is supplied to a laser drive circuit 3. The laser drive circuit 3 superimposes the high-frequency signal on a drive signal for driving a laser source. The drive signal on which the high-frequency signal is superimposed is supplied to the laser source of an optical pickup 2, and laser light is emitted from the laser source. An RF signal read from a disk 1 is supplied to a top hold unit and a bottom hold unit 9, and amplitude information of the RF signal is measured. A recording property measurement unit 10 measures a modulation degree or the like on the basis of the amplitude information of the RF signal. frequency of the high-frequency signal which is oscillated and outputted by the VCO4 in a reproduction operation for measuring the modulation degree or the like is set higher than frequency of the high-frequency signal which is oscillated and outputted by the VCO4 in a normal reproduction. <P>COPYRIGHT: (C)2012,JPO&INPIT |
