SVP UDT-4K, Руководство пользователя

Страница: 183 / 193

UDT-4K UHD HEVC Digital Camera Transmitter
MANUAL V0
183
C.3 DVB-S
DVB-S is the first generation of a standard for digital
broadcasting via satellite.
C.3.1 How Does It Work
DVB-S was designed to carry MPEG-2 transport streams over satellite. MPEG-
2 transport streams typically carry one or several television or radio services
multiplexed into a synchronous bit stream. All service components are divided
in short packets of 188 bytes, each identified by a Program Identifier in the
header of the packet.
Generic data can also be carried in MPEG transport streams, provided that it
is first encapsulated in the transport stream packets. The most common way
to encapsulate IP data into MPEG streams is called Multi Protocol
Encapsulation (MPE) and is also specified by a DVB standard.
The total bit rate of the transport stream is constant but can typically be
adjusted to match the needs of the satellite link. If the desired transport
stream rate is greater than the sum of the carried components, empty
packets are added to the stream by the multiplexer or the modulator. This
operation is called rate adaptation.
DVB-S uses QPSK modulation and concatenated error protection based on a
convolutional Viterbi code and a shortened Reed Solomon code.
Figure C.3: Future Extension Frames