SVP UDR-70, Руководство пользователя

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UDR-70 H.265 Portable Receiver
USER’S MANUAL V1.0
Annex D: Modulation Standards
This chapter describes the DVB-T/T2 and DVB-S/S2 standards, as well
as their features and the differences between them.
D.1. DVB-T
DVB-T is a technical standard that specifies the framing
structure, channel coding and modulation for digital terrestrial
television (DTT) broadcasting. It is a flexible system that
allows networks to be designed for the delivery of a wide range of
services, from HDTV to multichannel SDTV, fixed, portable, mobile,
and even handheld reception.
D.1.1. How Does It Work
DVB-T, in common with almost all modern terrestrial transmission
systems, uses OFDM (orthogonal frequency division multiplex)
modulation. This type of modulation, which uses a large number of
sub-carriers, delivers a robust signal that has the ability to deal with
very severe channel conditions.
DVB-T has technical characteristics that make it a very flexible
system:
• 3 modulation options (QPSK, 16QAM, 64QAM).
•
5 different FEC (forward error correction) rates.
•
4 Guard Intervals.
•
Choice of 2k or 8k carriers.
•
Can operate in 6, 7 or 8MHz channel bandwidths.
Using different combinations of the above parameters a DVB-T
network can be designed to match the requirements of the network
operator, finding the right balance between robustness and capacity.