| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical receiver which can discriminate a digital signal with an optimal threshold. SOLUTION: In an optical receiver, which is equipped with a photoelectric transducer that converts an optical signal S modulated by a digital signal into an electrical signal and has a bias voltage change its multiplication factor, and an automatic gain control amplifier 13 which amplifies a signal outputted from this photoelectric transducer, a peak value VP1 of a signal outputted from the automatic gain control amplifier 13 is detected by a first peak detection circuit 17, and a gain is controlled. Then, a peak value VP2 of a low frequency component extracted by a low-pass filter 21 is detected by a second peak detection circuit 22, and a difference between the two peak values VP1 and VP2 is added to a threshold which discriminates the digital signal. |
