If the line of sight is obstructed, sometimes an alternate path can be established using an intermediate site as a repeater.
如果视距被阻挡，则可利用某一中间地点做为中继站，以建立一条迂回路径。
2
In digital repeater, the application of digital intermediate frequency technology and realization of optical fiber transmission for distance will require for little Phase Noise of Phase-Locked Source.