| 摘要 |
In an optical transmission system automatic (or semi-automatic) fault location is effected by a loop-back component (10) connected to a terminal's transmitting equipment (3) via a first optical coupler (4) and to an output to which a receive power meter (9) can be connected. A launch power meter (8) can also be connected to the loop- back component(s). The component (5) includes switching means (10) which connects the first coupler to the launch power meter or to a second coupler to measure an estimate of power level received from a remote transmitter. In normal operation the receive power meter (9) if connected to a second coupler 7, measures a proportion of the power from a remote transmitter. If a fault occurs readings are taken with switching means in different settings and the results of these readings enable the fault to be located. The switching means can be an optical switch, or an optical coupler whose output to the second coupler goes via an on/off switch or an electrically adjustable attenuator. <IMAGE> |
