PURPOSE: To reproduce both ISO and CD specified optical disks by providing a switching means which turns ON the power source of a high frequency amplifier at the time of mounting the ISO specified optical disk, and turning OFF the power source of the high speed amplifier at the time of mounting the CD specified optical disk.
CONSTITUTION: When a disk discriminating means 51 judges that the CD specified optical disk is mounted, a switch SWO is turned OFF by a switching signal S50. Thus the input impedance of a high frequency amplifier 10 is made high, and entire currents from a photodetector 11 pass through a direct current amplifier 20. A signal inputted to the direct current amplifier 20 is amplified, and inputted to both an information signal processing circuit 30 and a servo signal detecting circuit 40 at the next stage. When the above mentioned disk discriminating means 51 judges that the ISO specified optical disk is mounted, the switch SWO is turned ON, a high frequency component Ir of the outputs of the photodetector 11 is amplified through a capacitor Ci by the high frequency amplifier 10 outputted and used for an information reproduction signal S10.
IZUMI HARUHIKO
TAGUCHI MASAKAZU
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