| 摘要 |
PURPOSE: To easily take out necessary signal at the tie of receiving data by means of transmission/reception of an optical signal. CONSTITUTION: The optical signal is supplied to a reception circuit 29 through a photodetector 28. An LPF 41 extracts out components up to a frequency desired to be canceled and a current detector 42 drives a current source 43. Then an output from the current source 43 is supplied to a subtracter 46. The subtracter 46 subtracts the component up to the frequency extracted by the LPF 41 from current supplied through a current detector 44 and a current source 45 and outputs the result through the output terminal 47. |
