| 摘要 |
PURPOSE:To surely attain a reception by inputting a pulse at a prescribed time from a carrier detection circuit after the end of the reception of a packet to the control terminal of a 3-terminal switch without deteriorating the reception sensitivity. CONSTITUTION:In finishing the reception of 1st and 2nd packets, a carrier detection circuit 8 detects the interruption of a reception signal and outputs the output of an output waveform of a carrier detection circuit being at VN [V] during times t2-t3 and t4-t5[sec] and at VT[V] in other times. Thus, the resistance between the 1st terminal 13 of the 3-terminal switch 9 and the 2nd terminal 14 is switched into from several MOMEGA to several hundreds of OMEGA. After the end of receiving the 1st packet 20, the anode potential waveform of the APD 1 is restored rapidly to 0[V] and the amplitude in the steady-state is obtained from the 2nd packet at the head in the output waveform of a main amplifier 6 and the minimum light receiving level is not deteriorated. |
