| 摘要 |
PURPOSE:To reduce the power consumption more than a conventional call-by-call system by applying power only to a photodetection circuit normally and detecting an AGC control voltage within a specified range in the said circuit so as to apply the power of the entire circuit. CONSTITUTION:An output of an AGC control voltage of an AGC3. A part of an output of the circut 5 supplies a bias current to an APD1 via a DC/DC converter 6 in this case and an output level of the AGC3 is made constant. In this case, the level of the desired optical input signal is taken in the range of P1-P2 in this case, output voltages of the circuit 5 with the levels P1, P2 are taken respectively as V1, V2, the reference voltages of comparator circuits 7, 7' are selected as V1, V2 for Vref1, Vref2, and when the input voltage of the comparator circuit 7 is larger than the Vref1 and the input voltage of the comparator circuit 7' is smaller than the Vref2, the comparator circuits 7, 7' are set so as to produce the output sigal, an AND gate 8 ANDs the signals, and its output signal applies the power of the other circuits so as to attain the application of power to all the circuits when the input level is in the range of P1-P2. |
