Ericsson MX8400, Справочное руководство

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Setting up the SFN Functionality
MIP: x Sync PID x FEC x STS x Pointer x
Mega-frame: x video x audio x video x ….. x MIP x …
Figure H.2 MIP/Mega-frame
For synchronization purposes, the MIP contains both a pointer and time reference
(STS) to the start of the next mega-frame start. The pointer is the number of
transport stream packets between the MIP and the first transport stream packet of
the succeeding mega-frame. The time reference is a count of 10 MHz clock cycles
between the latest pulse of the 1 PPS reference (derived from GPS) that precedes
the start of the mega-frame M+1 and the actual start of this mega-frame M+1.
The SFN adapter and Modulators are frequency locked to a GPS 10 MHz reference
clock derived from GPS.
The Modulators make use of the information in the MIP to determine the following
information:
•
The start of the mega-frame within the incoming transport stream.
•
The network delay that transport stream has experienced getting to each
Modulator sites.
The Modulator equalizes the delays and broadcast the data in a synchronized
manner.
H.2 SFN Adapter Requirements
The MX8400 main host controller has the following SFN adapter functionality.
•
The MX8400 supports up to 16 output transport streams with SFN data.
•
The insertion of MIPs into an output transport stream complies with TS 101 191
V1.4.1.
•
The MX8400 does not preclude the support for all valid SFN modulation modes.
•
The SFN data for each output transport stream can be configured independently
of each other via nCompass Control (nCC).
•
The SFN data for each output transport stream is configured via nCC
•
It is possible to have a combination of SFN and non-SFN output transport
streams.
•
There are no restrictions on multiplexing functionality when the MX8400 is
configured as an SFN adapter.
2/1553-FGC 101 1014 Uen B H-4