| 摘要 |
PURPOSE:To improve a signal transmitting capability by enlarging S/N in a low band area while maintaining S/N in a high band area and expanding a virtual MTF. CONSTITUTION:A magneto-optical disk 1 is irradiated with a reproducing light L from a reproducing optical pickup, 2 an effective reading aperture is limited by utilizing a temperature distribution in the spot of the reproducing light 1 and an information signal recorded in the magneto-optical disk 1 is reproduced. Reference optical pickups 4a and 4b for radiating reference lights are disposed on the front of the reproducing optical pickup 2. Based on reference signals Sa and Sb from these reference optical pickups 4a and 4b the spatial frequency of an information pit recorded in the magneto-optical disk 1 is detected and based on this detected spatial frequency and a preset reference spatial frequency, the optical intensity of the reproducing light 1 is made changeable, or a feedback circuit 5 for ON/OFF-controlling an external magnetic field Hr generated from an external magnetic field generator 3 is provided. |
