SVP UDT-4K, Руководство пользователя

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UDT-4K UHD HEVC Digital Camera Transmitter
MANUAL V0
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C.2 DVB-T2
DVB-T2 is the world’s most advanced digital terrestrial
television (DTT) system, offering more robustness, flexibility
and at least 50% more efficiency than any other DTT system. It supports SD,
HD, UHD, mobile TV, or any combination thereof.
C.2.1 How Does It Work
Like its predecessor, DVB-T2 uses OFDM (orthogonal frequency division
multiplex) modulation with a large number of subcarriers delivering a robust
signal, and offers a range of different modes, making it a very flexible
standard. DVB-T2 uses the same error correction coding as used in DVB-S2
and DVB-C2: LDPC (Low Density Parity Check) coding combined with BCH
(Bose-Chaudhuri-Hocquengham) coding, offering a very robust signal. The
number of carriers, guard interval sizes and pilot signals can be adjusted, so
that the overheads can be optimised for any target transmission channel.
C.2.2 DVB-T2 New Features
The DVB-T2 standard has several improvements in comparison with the DVB-
T standard.
FEC coding
In the error correction stage, the DVB-T2 standard implements a combination
of LDPC codes with BCH codes. LDPC codes allow a close performance to
Shannon limit and the BCH codes are used to eliminate the floor error of the
LDPC codes.
Figure C.1: LDPC and BCH codes
Constellation Rotation
This new feature consists of a rotation of some degrees of the constellation.
With this rotation, dependence between the I and Q components of the signal
is achieved. This means that with only one component (the I or the Q) it is
possible to know exactly the symbol to which it belongs.