Cofdm Input (Tt1260/Hwo/Cofdm678); Ttv G.703 Input Card (Tt1260/Hwo/G703); Ip Input Card (Tt1280/Hwo/Ip) - TANDBERG TT1260 Reference Manual

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6.2.4

COFDM Input (TT1260/HWO/COFDM678)

The COFDM digital terrestrial input card demodulates COFDM signals. The board is able to be
used in all RF channel bandwidths (6, 7 and 8 MHz).
6.2.5

TTV G.703 Input Card (TT1260/HWO/G703)

The TTV G.703 input card receives a transport stream directly from a PDH network.
For technical specifications for the TTV G.703 card, see Annex B, Technical Specification.
6.2.6

IP Input Card (TT1280/HWO/IP)

The IP Input card provides a 10/100BaseT Ethernet port, on which a transport stream can be
received in UDP packets at up to 60 Mbit/s.
The mapping of MPEG-2 TS packets into IP data frames is done according to the protocol
stack shown in Figure 6.1. The figure shows the Protocol Stack in use when mapping MPEG-2
into IP frames and Ethernet.
Control traffic for in-band
management
(telnet, http, snmp)
Figure 6.1: The Protocol Stack
The MPEG-2/DVB layer is specified in ISO/IEC IS 13818 – Generic Coding of Moving Pictures
and Associated Audio. The UDP layer is compliant with RFC768 – User Datagram Protocol. A
configurable number of 188-byte MPEG-2 TS packets are mapped straight into a UDP frame
with no additional overhead. The MTU for Ethernet is usually 1500 bytes. This limits the
number of MPEG-2 TS packets per UDP frame to lie within one to seven.
The IP layer is according to RFC791 – Internet Protocol Specification.
Figure 6.2 shows a more detailed picture of the MPEG-2 data transfer. TS-packets are
mapped in a datagram, using User Data Protocol (UDP), Internet Protocol (IP) and Ethernet.
Page 6-6
TCP/UDP UDP – User Datagram Protocol
Transport layer - IP
Link layer – 10/100BaseT Ethernet
MPEG-2 Transport Stream
(Multi-Program Transport
Stream or Single-Program
Transport Stream)
MPEG-2/DVB layer
Reference Guide: TT1260 Contribution Receiver
ST.RE.E10100.3