| 摘要 |
PURPOSE:To attain time matching with high accuracy by obtaining the delay time of a transmission line from the propagation speed of the transmission line of plural slave stations, the transmission line length and a closed transmission time required when the signal sent from one station is returned again to said station so as to correct the reference time. CONSTITUTION:A timer means 14 counting the time when a transmission frame sent from one station is circulated through each station and an arithmetic means 16 calculating the transmission delay time between the master station and the slave station based on the time and the propagation speed of the transmission line connecting the stations measured in advance and the transmission line length, are provided. Then the time being the addition of the transmission delay time to the reference time is set as the present time of the slave station. Thus, the time matching with high accuracy is attained independently of the transmission line medium, the transmission line length and the constitution of the line. |
