NetXpress LX & CM-30R Installation & Operation Manual
2
–
Functional Design
Version 1.1
2-14
GatesAir, Inc.
Intraplex Products
Figure 2-4. Timing Synchronization
NetXpress LX units can derive system timing in one of four ways:
1.
An internal clock is available, based on a local oscillator within the unit (Internal Timing).
2.
An external clock can be applied to the unit (External Timing).
3.
An incoming IP unicast or multicast stream (Stream Timing), thereby synchronizing itself to the
NetXpress LX unit that generated the stream.
4.
SynchroCast, which incorporates a blend of Stream and External timing from GPS receivers.
Simple point-to-point systems commonly use a combination of internal and stream timing. Figure 2-5
shows the unit at site A 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 2-5. Point-to-Point Timing Synchronization
The configuration advantage in Figure 2-5 is simplicity of implementation. No external timing sources
are required. This configuration 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 2-6
shows such a system, with Site A using internal timing and the remaining sites using stream timing to
achieve synchronization to Site A.
NetXpress LX
A
NetXpress LX
B
NetXpress LX
D
NetXpress LX
C
Multicast Audio
Stream 1
Audio Stream 2
NetXpress LX units at sites A and
C must have synchronized
system clocks so that the
NetXpress LX unit at site D can
properly receive and process its
two incoming audio streams.
NetXpress LX
A
NetXpress LX
B
INTERNAL
TIMING
STREAM
TIMING
