| 摘要 |
PURPOSE:To remove irregular noise and to improve a signal characteristic by adding or subtracting a reflection side signal and a transmission side signal with the aid of reproduction signals for reflected light and transmitted light. CONSTITUTION:The reflected light of a light beam projected on a medium 1 makes incident on a beam splitter 13, while reflected light coming out of the splitter 13 joins a reflected light four division light receiving element 16. On the other hand, the transmitted light of the light beam projected on the medium 1 joins a transmitted light receiving element 20 through a transmission side detection element 3. A reproduction signal 101 that the element 16 outputs and a reproduction signal 201 that the element 20 outputs are inputted to an arithmetic circuit 30. Here the signal 201 generates a positive signal voltage when it passes by a recording bit, and the signal 101 generates a positive signal. Therefore the circuit 30 outputs a cumulative signal 130. At that time a noise component which is caused by the partial fluctuations of the transmissivity and reflectance of the optical medium 1 is canceled and minimized, thereby increasing a signal component. |
