OPTICAL FIBER PARALLEL TYPE TRANSMITTING DEVICE

摘要

PURPOSE:To economically shape the waveform in each optical fiber without using any monitor line that is exclusively used for setting the threshold value by using one of those signals obtained by applying the photoelectric conversion to the outputs of plural optical fibers for detection of the threshold value and then using the detection output as the threshold value of each comparator. CONSTITUTION:A photoelectric converter 4 converts the optical signal 1-n of an optical fiber 1 into electric signals via an optical input terminal 3 of a receiving optical device 2. These electric signals are supplied to the input terminals A of comparators 5. The output of a converter 4 (n) is supplied to a threshold value detecting circuit 6, and the detection output of the circuit 6 is supplied to each input terminal B as the threshold value signal of each comparator 5. Then each comparator 5 decides the logical value of the input electric signal of the terminal A based on the input threshold value signal of the terminal B and then performs the waveform shaping. Furthermore the circuit 6 can easily detect the threshold value of the input optical signal of the converter 4(n) since this signal has its mark rate of about 0.5 and also a satisfactorily high quenching ratio. Thus the economical waveform shaping is attained without using any monitor line exclusive for setting the threshold value nor a light emitter and a light receiver.