| 摘要 |
PURPOSE:To make it easy to extract or to insert a low-order group signal by extracting a required low-order group signal by a selector after the received optical signal of a high-order group is converted to plural low-order group signals, inserting a new low-order group signal, and sending it out after converting it to an original high-order group signal. CONSTITUTION:The optical signal of the high-order group is converted to an electrical signal at an optical receiver 1 and furthermore, it is converted to the low-order group signal at a serial/parallel converter 2 and is supplied to a selector 4. At this stage, the selector 4 selects the signal to be extracted out of the low-order group signals and supplies it to a destuff/stuff.INF unit 5 and a signal DS3 is outputted to an outside. On the other hand, the signal DS3 supplied from the outside is inserted to the frequency band of an extracted low-order group signal through the destuff/stuff.INF unit 5 and the selector 4 and is converted to the high-order group signal and is outputted as the optical signal. |
