Radyne ComStream TIERNAN SE4000, Installation And Operation Manual

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Introduction SE4000 MPEG-2 Contribution Encoder
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2.5.2 Configuring the DTE and SE4000 Clock Interfaces
After you have cabled the data termination equipment (DTE) to the SE4000, you must determine
the most effective SE4000 and DTE clock source arrangements. There are three different ways to
configure the clock interface for the SE4000 and the DTE:
•
Clock Interface Configuration 1 is the most reliable clock source arrangement. This
configuration requires the DTE to provide a clock (TT) synchronous with the data (SD) to
the SE4000.
•
Clock Interface Configuration 2 is the second most reliable clock source arrangement.
This configuration is used when the DTE cannot turn around the ST, but has an internal
clock source that can be provided as TT to the SE4000.
Clock Interface Configuration 3 is the least reliable clock source arrangement - it should only be
used if the first two clock configurations cannot be used. In this configuration the SE4000 is
configured to use ST to latch the data.
2.5.2.1 Clock Interface Configuration 1
The most reliable auxiliary data channel clock source configuration requires the DTE to provide a
clock (TT) synchronous with the data (SD) to the SE4000. This scenario allows the SE4000 to
latch the data using a clock that has traveled the same path as the data, which ensures that both
the clock and the data are received in phase at the SE4000.
The following block diagram shows the clock configuration for a DTE configured to turn around
the ST clock source, and a SE4000 auxiliary data channel configured for an external clock
source.
Notice in the illustration that the switch for the SE4000 auxiliary data channel clock source is
configured for external even though the SE4000 is providing ST to the DTE.
In this configuration, the SE4000 provides clock (ST) to the DTE. The switch for the DTE clock
source is configured to accept the external clock (ST) provided by the SE4000. The DTE uses the
ST to time the data, sends the data to the SE4000 on SD, and returns the ST to the SE4000 on
TT. The SE4000 uses TT to latch the data.
The SE4000 auxiliary data channel must be configured for an external clock source to accept TT
from the DTE.