Features
User Manual for AZ110 Broadcast Satellite Modulator with ASI interface
version 3.2
97
SHAPING THE FUTURE SATELLITE OF COMMUNICATIONS
8.5
Equalink
BER performance degradation due to transmission channel impairments is
becoming increasingly important in DVB-S2 systems operating with higher order
modulation formats (16APSK, 32APSK), in particular at the higher symbol rates.
The Equalink concept effectively optimises satellite link performance by
counteracting these effects. Newtec DVB-S2 modulators equipped with the
Equalink™ feature contain both linear and non-linear predistortion functions which
can be individually enabled/ disabled.
Equalink operating principle:
• Optimum predistortion is computed off-line based on specified distortion
characteristics;
• Resulting predistortion table(s) are uploaded to the modulator and activated.
Link performance can be expressed in terms of Bit or Packet Error Rate (BER or
PER) versus Energy-per-symbol to Noise density ratio (Es/No).
For a communication channel over a satellite link, the overall link performance can
be severely degraded by channel impairments. Examples of such impairments are
interference (Adjacent Channel Interference (ACI) and Co-Channel Interference
(CCI), Inter-Modulation (IM), Adjacent Satellite Interference (ASI)...), phase noise,
signal distortions, etc.
Please refer to the Equalink™ User Manual for a full description of
this feature.
