| 摘要 |
PURPOSE:To prevent the generation of an excess voltage and waveform distortion by connecting a resistive element in parallel with a photodiode, connecting one terminal of a parallel connection circuit to a reference level, and connecting the other terminal to an input terminal of a signal processing circuit. CONSTITUTION:In order to prevent the saturation of a signal processing circuit caused by excess optical input in an optical reception circuit, a parallel connection circuit comprising a photodiode 1 and a resistive element 2 is provided, one terminal of a said parallel connection circuit is connected to a reference level and the other terminal of the parallel connection circuit is connected to an input terminal of the signal processing circuit 3. Thus, since the maximum value of the signal input to an amplifier 3 is kept to a constant low amplitude, the saturation of the amplifier 3 is prevented and when the optical input is small, the gain the same as a conventional circuit is obtained. |
