| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve an SNR of an optical detection processing circuit including a photodetector more than in the conventional practice in a reproducing device adopting a homodyne system. <P>SOLUTION: A first current-voltage conversion part for performing current-voltage conversion for first combined current obtained by combining output current from a cathode of a first PD (photodiode) with output current from an anode of a second PD by connecting a cathode of the second PD to an anode of the first PD, and a second current-voltage conversion part for performing current-voltage conversion for combined current obtained by combining output current from the anode of the first PD with output current from the cathode of the second PD are provided. A differential signal generating part for generating a differential signal between an output by the first current-voltage conversion part and an output by the second current-voltage conversion part is also provided. Since the reproduction signal can be acquired by using not only the combined current of the output current of the anode of the first PD and the cathode of the second PD but also the combined current of the output current of the cathode of the first PD and the anode of the second PD, a reproduction signal level can be increased and the SNR can be improved. <P>COPYRIGHT: (C)2012,JPO&INPIT |
