Newtec AZ110 - Pilots in DVB-S2; What Are Pilots

Technology
User Manual for AZ110 Broadcast Satellite Modulator with ASI interface
version 3.2
77
SHAPING THE FUTURE SATELLITE OF COMMUNICATIONS
ACM
In Adaptive Coding and Modulation mode, the modulation parameters of the
Baseband frames can vary over time, according to the instantaneous receiving
conditions of the site where the frame will be received. In ACM there is a feedback
mechanism between the demodulator and the modulator. This feedback
mechanism dynamically tells the modulator which modulation parameters to use
for each baseband frame. ACM allows operating satellite links with almost no
margin, since the system adapts automatically to fading or interference conditions.
HUBHUB
.
.
.
16APSK 5/6
8PSK 3/4
16APSK3/4
16APSK2/3
Co/No
measurements
Figure 42- ACM
Newtec’s implementation of ACM for applications is called FlexACM. It relies on an
unique very accurate linear and non-linear distortion measurement technology in
the demodulator (called NoDE) and advanced traffic shaping technologies in the
hub.
7.2 Pilots in DVB-S2
7.2.1 What are Pilots
Pilots are unmodulated symbols grouped in blocks that can be added on the
physical layer framing level.