Technology
User Manual for AZ110 Broadcast Satellite Modulator with ASI interface
version 3.2
74
SHAPING THE FUTURE SATELLITE OF COMMUNICATIONS
7.1.2
DVB-DSNG
The DVB-DSNG standard is an extension to the DVB-S standard introduced for
professional applications such as Digital Satellite News Gathering or television
contribution services. DVB-DSNG introduces higher order modulation schemes
(8PSK and 16QAM) and additional signal roll-off factors.
The transported signals are the same as for DVB-S.
7.1.3
DVB-S2
DVB-S2 is the second generation of the DVB standard for broadcast of satellite. It
introduces new correction codes (BCH and LDPC) that are typically 30% more
efficient than the codes used in DVB-S. The DVB-S2 standard also introduces a
range of new features such as:
•
Higher order modulation schemes 16 APSK and 32 APSK;
•
Sharper roll-off factors;
•
A new framing structure called “baseband frames”;
•
The ability to vary the modulation parameters dynamically. This is used in
modes called “Variable Coding and Modulation” and “Adaptive Coding and
Modulation”;
•
The ability to carry several signals on a single satellite carrier, without
multiplexing in front of the modulator. This is called “multi-stream””;
•
The ability to carry signals other than MPEG transport stream. This is called
“Generic Stream”.
These features are further explained in the following sections:
7.1.3.1
DVB-S2 Framing Structure
DVB-S2 applies the error correction coding and the modulation to large frames of
data called baseband frames. A DVB-S2 baseband frame is either 16200 bits
(short frames) or 64800 bits (normal frames). The content of a frame can be a
section of a transport stream, or any type of data, framed or unframed (Generic
Stream).
Note that the DVB-S2 standard specifies how to encapsulate transport streams into
baseband frames, but not how to encapsulate IP data into baseband frames.
