Technology
User Manual for AZ110 Broadcast Satellite Modulator with ASI interface
version 3.2
78
SHAPING THE FUTURE SATELLITE OF COMMUNICATIONS
7.2.2
Why are pilots used in DVB-S2
•
Reduce the phase noise influence;
Phase noise is created by the frequency components around the main carrier
frequency.
This noise contains components at many frequencies with randomly changing
phase.
•
Pilots are used to increase the reliability and the continuous receiver
synchronization.
7.2.3
When are Pilots Used in DVB-S2
It is advised to use pilots in the following cases.
•
In ACM mode (always on).
•
When a noticable amount of phase noise is present;
•
At low data rates;
•
When distortion is present on the signal for example due to non linearity.
•
When using one of the following ModCods. (this is due to the ModCod
structure)
-
8-PSK 3/5 and 2/3
-
16-APSK 3 /4
-
32 APSK 3/5
7.3
Processing Mode
Newtec Azimuth devices can operate in several processing modes to carry
transport streams and/or IP data.
These processing modes indicate how the incoming data or signal is interfaced to
the modulator or demodulator and how it is transmitted over the modulated carrier.
The most important method to interface the signal to the modulation equipment is:
•
ASI(TS)
: The incoming/outgoing signal is an MPEG transport stream and is
entering the modulator or leaving the demodulator via an ASI interface;
