| 摘要 |
PURPOSE:To mark a position of fault point of submarine cable by providing monitoring oscillators of different frequency for each repeater, transmitting pulselike signal for a short time that allows separation of frequency, and measuring the reflection from the fault point. CONSTITUTION:When there is a fault point of submarine cable between repeaters R3' and R4', a pulselike signal of time tau is transmitted from a terminal station 1' at alloted frequency of low group band. Switching signal detecting and switching driving circuits 4-1-4-3 of repeaters R1'-R3' detect the signal and oscillate monitoring transmitter for high group HSV'-1-HSV'-3 for a time tau. Signals of HSV'-1, HSV'-2 are transmitted toward a terminal station 2'. However, as the direction of transmission is reverse, the signals can not pass repeaters R2', R3'. The signal of HSV'-3 is reflected at the fault point to become signal of forward direction and arrives at the terminal station 1'. The position of the fault point can be known accurately by the signal.
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