| 摘要 |
In a passive optical telecommunication system wherein a plurality of decentralized stations are respectively connected via their own respective light waveguide subscriber line to an optical brancher that is connected, in turn, directly or via at least one further optical brancher to a common light waveguide terminal of the central station via a light waveguide bus, the decentralized station and the centralized station each transmitting and receiving optical digital signals in common-frequency operation, a transmission/reception circuit at each decentralized station is provided to avoid a degradation of the reception sensitivity of the central station corresponding to the bit pattern of its transmitted signal. This transmission/reception circuit includes a reception signal inverter connected between the output of the opto-electrical transducer and the input of the electro-optical transducer, and an optical delay line whose delay time is matched to the operating time of the electrical reception signal invertor is inserted between the output of the electro-optical transducer and the light waveguide subscriber line. The transmission/reception circuit maintains the sum of the received signal, and the part thereof which is unavoidably reflected, at a constant level.
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