| 摘要 |
PURPOSE:To constitute an optical receiver immune to an external noise by giving an output of a comparator connected to a feedback circuit to an input of another comparator and outputting the output externally. CONSTITUTION:An optical signal 1 inputted from a photodetector 2 is amplified by an amplifier 3. A reference power supply 5 outputs the nearly equal voltage as the bias voltage of the output of the amplifier 3 and a voltage holding section 10 holds a nearly half the difference between the output of the amplifier 3 and the reference voltage 5. The output of the comparator 12 connected to a holding section 10 is not outputted directly at the outside of the photoreceiver and outputted externally from the output 22 after passing through the compara tor 19. Thus, even if the voltage of the output 22 reaches an abnormally high voltage due to an external noise, the feedback circuit 16 is not operated by the voltage and the holding section 10 is not affected at all. Thus, when the external noise is missing, the output 22 restores to the potential before the noise is applied quickly. Thus, the optical receiver immune to the external noise is attained. |
