Cambium PTP 450 series, Руководство пользователя

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Configuration options for TDD synchronization PTP 450 User Guide
ptp-450 (July 2014)
2-77
Figure 22 One unsynchronized BHM in cluster resulting in self-interference
The result is self-interference. In this scenario, the self-interference can be avoided only by synchronizing the TDD
transmit cycles of all BHMs that operate in the same frequency band.
An BHM that is isolated by at least 5 miles (8 km) from any other equipment can generate and pass sync pulse
without GPS timing and not risk that interference will result from the generated sync. In any other type of link, sync
should be derived from GPS timing.
Advantage of GPS synchronization
Although the embedded timing generation capability of the BHM keeps a precise clock (configuration parameter
Sync Input set to Generate Sync Signal ), no trigger exists to start the clock at the same moment in each BHM of a
cluster. So, the individual BHM can synchronize communications between itself and registered BHSs, but cannot
synchronize itself with other modules, except by GPS timing (shown in Figure 23 ).
Figure 23 GPS timing throughout the network
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