| 摘要 |
PROBLEM TO BE SOLVED: To automatically perform network synchronization without being conscious of the fact that a specified channel is a channel exclusive for a fixed clock path. SOLUTION: A frequency difference detection part 11b detects the frequency difference of the WC and RC of an uplink FIFO 11a. An insertion stuff ratio decision part 11c calculates an insertion stuff ratio in a CH 11 on the basis of the frequency difference detected by the frequency difference detection part 11b. In an insertion stuff ratio detection channel decision part 19a, the insertion stuff ratios of the respective channels are compared with one another. The channel whose insertion stuff ratio is closest to about 17.65 ppm is decided when multiplexing 4 CH of 2.48832 Gb/s to an OTU 2, and the channel whose insertion stuff ratio is closest to about 35.46 ppm is decided when multiplexing 4 CH of 9.95328 Gb/s to an OTU 3. In such a manner, the channel for transmitting a highly accurate reference clock is detected on the basis of the result of deciding the channel whose insertion stuff ratio is closest to a prescribed value. COPYRIGHT: (C)2010,JPO&INPIT
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