Dvb-S Signals - Promax PRODIG-3 Manual Del Usaurio

USER'S MANUAL. PRODIG-3
TPS in lock
The TPS (Transmission Parameter Signalling) are decoded. The TPS are carriers
(17 in the 2k system and 68 in the 8k system) modulated in DBPSK, containing
information related to the transmission, modulation and codification: Modulation
type (QPSK, 16-QAM, 64-QAM), Hierarchy, Guard Interval, Viterbi Code Rate,
Transmission mode (2k or 8k) and Number of the received frame.
MPEG-2
Correct detection of a MPEG-2 signal.
5.14.5.2

DVB-S signals

Once determined the parameters of QPSK signal, it will be possible to measure
BER. Following is shown the BER measurement before the error corrections: BER
before the FEC: CBER.
MPEG-2
Figure 27.- Screen of CBER measurement (QPSK signals).
In a digital reception system for satellite signals, after the QPSK decoder two
different correction methods are applied (see following Figure). Obviously, each time we
apply an error corrector to a digital signal, the error rate changes, therefore if we
measure in a digital satellite television system, for example, the error rate at the output
of the QPSK demodulator, at the output of the Viterbi decoder, and at the output of the
Reed-Solomon decoder, we obtain nothing more than different error rates. This is the
reason because the BER measurement is provided before FEC, after Viterbi (VBER).
03/2008
-6 -5 -4
FREQ: 1781.94 MHz
5037 kHz
DL-Ku: 12382.0 MHz
CH: 99 MHz
Figure 28.- Digital reception system via satellite.
-3 -2 -1
C/N: 0.2 dB
POWER: 51.5 dBµV
MER: 10.9 dB
» CBER: 9.7E-4
VBER: 5.2E-8
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