| 摘要 |
PURPOSE:To measure a propagation delay time invariably accurately by sending a synchronizing signal out of one of two terminals between which time synchronization is attained, receiving and returning the signal at the other terminal simultaneously, and receiving it at the transmitting terminal and detecting the phase difference between the transmission and reception for the calculation of the propagation delay time. CONSTITUTION:A block I for time measurement and a block II for synchronizing signal transmission are provided to terminals A and B between which time synchronization should be attained; and a block III for synchronizing signal generation and a microcomputer (MC) 11 are provided to the terminal A and impedance converting circuits 6a and 6b of blocks II of the terminals A and B are connected through pilot wires 7a and 7b to constitute a synchronzing signal two-way transmission means. Then, the counters 2 at the terminals A and B are cleared with the constant-period signal of the block II, and at the same time the block III detects the phase difference between the synchronizing signal sent back by the terminal B and the generated synchronizing signal; and the MC11 calculates the propagation delay time from said phase difference and the phase difference of the synchronizing signal and corrects a difference in surge arrival time. |
