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T-Gate is a blade system. Each blade receives a digital
TV broadcast, filters the required programmes and retransmits
them to multiple targets on the local network. By using
different receivers on the blade variants we have a
terrestrial and a satellite version. With a suitable
MPEG-2 encoder and RF tuner we can make baseband video
and analogue TV versions.
Digital TV channels are
broadcast from terrestrial or satellite transmitters as
multiplexed MPEG-2 transport streams, formatted according
to the DVB standard. Each T-Gate blade acts as a gateway
between a DVB multiplex and an Ethernet network. In the
case of DVB-S (satellite) and DVB-T (terrestrial), each
blade is capable of transporting an entire DVB multiplex
onto the Ethernet network. This represents a data rate
of about 45Mbit/s and 24Mbit/s respectively.
The DVB multiplexes usually contain several TV and radio
channels. The T-Gate blades can be configured to filter
the channels into separate network streams to avoid flooding
the network clients with data. Up to seven separate UDP
streams can be configured. Each network stream would usually
contain a TV channel or several radio channels.
Up to 16 packet IDs can be selected from the incoming
DVB multiplex for each UDP stream. These can include audio,
video, subtitles, system information and data. The network
streams will contain modified PAT and PMT packets that
correctly describe the new transport stream content.
Each T-Gate blade is running Linux to provide a TCP/IP
stack on a RISC based CPU. This provides a UDP command
interface to the blade's features as well as Telnet, RS232
and HTTP interfaces.
T-Gate requires very little configuration, much like a
TCP/IP print server or a simple broadband router. In many
cases the device will be automatically tune to a DVB multiplex
and start streaming a TV channel.
If T-Gate is being used as part of a sophisticated entertainment
or monitoring environment, our off-the-shelf scheduling
and stream capture software, running on external server
hardware can be added. Programmatic control can then be
achieved via the UDP command interface for all the T-Gate
blades in the system.
T-Gate is designed to fit onto a slightly extended Eurocard
size PCB. Power and RF are supplied to the rear of the
board, with all remaining I/O connectors and LEDs on the
front edge. Enclosure options include a 3U 19" rack
mount chassis for up to 12 blades or small desktop cases
for a single blade. The rack mount chassis supplies power
and cooling to the blades and individual blades can be
mixed and matched.
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| Networking |
| 100Base-T full
duplex Ethernet interface |
| Front
end Information (DVB-T) |
Input/Output:
IEC socket + plug 75 ohm
COFDM
Modes: 2K and 8K supported
Frequency
Bands: 49-161MHz, 161- 444MHz and 444861MHz
Modulation: QPSK, 16QAM, 64QAM
Guard
Interval: 1/4, 1/8, 1/16, 1/32
Error
Correction: Reed Solomon and Viterbi |
| Configuration |
| Interface provided
by RS232, Telnet and HTTP |
| Dimensions |
| 235x100 mm
5HP (25.4 mm) high |
| Stream
Targets |
Up to 7 unicast
or multicast UDP streams. Each stream can contain
16 PIDs from the
original DVB transport stream or alternatively the
entire DVB transport stream can
be streamed provided the total bandwidth does not
exceed 45Mbps. |
| Management
Streams |
Status and
EPG information (where available) can be provided
as XML
formatted data in UDP streams to preconfigured targets.. |
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