GatesAir Intraplex NetXpress, Инструкция по установке и эксплуатации

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Intraplex NetXpress IP Multiplexer 2—Functional Design
Version 3.05
2-16 GatesAir, Inc.
Intraplex Products
In simple point-to-point systems, it is common to use a combination of internal and stream timing.
Figure 2-7 shows the unit at site A is set to Internal Timing, utilizing its local internal oscillator. The
unit at Site B derives timing from the audio stream transmitted from site A to site B.
Figure 2-7. Point-to-point Timing Synchronization
The advantage of the configuration in Figure 2-7 is simplicity of implementation. No external timing
sources are required. This can be extended to multiple site systems by designating one site as the
master timing location and having the rest of the sites derive timing from that site. Figure 2-8 shows
such a system, with site A using internal timing and the remaining sites using stream timing to
achieve synchronization to site A.
Figure 2-8. Stream Timing Synchronization
This method of timing distribution can be very simple and efficient in cases where programming
streams are emanating from one master site to all the remaining sites. However, programming may
be generated at multiple sites within the network, and these program source sites may not all receive
program streams from the master site that can be used as timing sources (Figure 2-9). In this
example, Site A is the master timing source, but site C does not receive a stream from site A and
therefore cannot synchronize its outgoing stream to the rest of the network. As a result, the two
streams received at site D utilize different synchronization sources and cannot be properly received
and decoded.
NetXpress
A
NetXpress
B
INTERNAL
TIMING
STREAM
TIMING
NetXpress
A
NetXpress
B
NetXpress
C
INTERNAL
TIMING
STREAM TIMING
STREAM TIMING
NetXpress
D
STREAM TIMING
Sites B, C, and D use stream timing to
derive timing from master site A.