DTV 720 USER’S MANUAL
800043-01 Rev. C 36 www.wegener.com
Following normal boot-up, the Home screen will appear as described in section 3.4 Front-
Panel Operation on page29 and the LEDs reflect the actual state of the unit.
Initialization
Failure
When in Initialization Failure mode, the unit is essentially dead. There is no ASI output, the
alarm relay is de-energized (alarm state), the Alarm LED is ON, and the unit does not
attempt acquisition of input streams. Call Wegener Customer Service.
3.6 Transport Stream Processing
Refer to ISO 13818-1 for supporting details on the structure of MPEG Transport Streams.
Input to
Output
Processing
The basic DTV 720 has two ASI inputs (and optionally two RF inputs or two more ASI
inputs). Program data from these inputs are multiplexed and output on two duplicate ASI
outputs. The unit processes the inputs, selects programs based on user input, and pro-
vides an output signal on the ASI outputs (and optional DHEI or GbE output). The pro-
cessing includes program number changes as selected. Based on user selection, certain
programs may be selected and then passed to the ASI output with time stamping updated.
PSIP
Structure and
Program
Selection
Within the transport stream, there are PIDs carrying tabular information on that stream.
The PAT describes all the programs available. The program number identifies each pro-
gram in the transport stream. When a source of data is acquired, the stream is passed to
the internal transport demultiplexer. This circuit then extracts the PAT and PMT informa-
tion and provides this information to the user via the Stream Info and Configuration pages
of the web interface. The user may then select programs to be included in the ASI output,
as described in section 3.2 Ethernet/Web Browser Control.
IRT Mode WARNING
Do not select IRT mode unless using the DTV 720 with Motorola or General Instruments
equipment. Using IRT in other situations may have unexpected results.
NOTE: When using IRT mode, PSIP must be disabled.
With systems using the Motorola IRT product, certain additional elements must be
included in the output transport stream. In such systems, be sure to enable the DTV 720’s
IRT Mode by selecting IRT Mode ON from the web browser interface. (See Control and Sta-
tus Page on page15.) When the IRT Mode is ON, the DTV 720 performs the actions listed
below:
• A CAT (Conditional Access Table) PID (0x0001) is included and a CA system
descriptor is added in this packet pointing to a reserved location (PID 0x0FF9) for
the EMM (Encryption Management Message).
• For each program in the stream, a CA descriptor pointing to itself is added in the
PMT. This is a null ECM (Encryption Control Message).
• To the PAT, Program 0 (NIT) is added, pointing to PID 0x0FFE which carries the STT
(System Time Table) clock information.
• The NIT (Network Information Table) must also be present in the transport stream.
This PID (0x0FFE) is created at the uplink and is passed through.
To Next Page
Loading...