| 摘要 |
<p>PURPOSE:To obtain a device which inexpensive and has high reliability, by detecting a collision by use of a timer and a detecting circuit of a receiving signal, and also giving a redundant bit to the head part of a transmitting signal. CONSTITUTION:As for a transmitting data inputted to a transmission controlling circuit 34, a redundant bit of fixed length is given to its head part by a redundant bit generator 35, and thereafter, said data is sent to a transmitter 2. As a result, a transition detecting circuit 31b outputs a significant output signal 37 to an AND circuit 30b by the time set by a timer 32. As for the timer 32, the time being equal to a propagation delay time extending from the transmitter 2 of the own station to an output of a waveform shaping circuit 9 through a star coupler 4 is set. When an optical signal of other station is received before receiving an optical signal of the own station, an output signal 10c of the circuit 9 is inputted to an integration circuit 26. A comparator 28 outputs a significant signal to the AND circuit 30b. The circuit 30b applies AND to outputs of the circuit 31b and the comparator 28, and outputs a collision detecting signal 33. The transmission controlling circuit 34 stops immediately transmission of a signal of the own station.</p> |
