| 摘要 |
PURPOSE:To enable automatic failure diagnosis of system and to decrease the restoration time at system down , by transmitting failures such as open transmission line and out of synchronism of station with one common transmission bus, in a loop system transmitting system. CONSTITUTION:A signal input to a reception circuit 18 via a transmission line 54 is respectively fed to a timing pickup circuit 19, demodulation circuit 26, and detection circuit 31 monitoring the presence of reception signal. The output of the timing pickup circuit 19 is fed to a PLL20 and fed to a control section 29 as reception clock and reception data. The transmission data from the control section 29 and the clock are fed to a modulation circuit 28 and fed to the next stage station via a transmission circuit 55 at the transmission circuit 30. If the reception signal transmitted from a transmission line 54 is absent, and if out of synchronism is caused, the detection circuits 31 and 27 detect it, logical sum is taken at a gate circuit 32 and the transmission restricting means 60 is operated with the output of the modulation circuit 28. |
