Dvb-S/S2 And Dss Signals - Promax US TV EXPLORER II Manual De Uso

USER'S MANUAL. US TV EXPLORER
5.14.7.4

DVB-S/S2 and DSS 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.
-6
FREQ:
DL-Ku:
CH:
MPEG-2 TS
Figure 38.- Screen of CBER measurement (QPSK signals).
In a digital reception system for satellite signals (DVB-S), 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 (CBER) and after
Viterbi (VBER).
Figure 39- Digital reception system via satellite. (DVB-S).
-8
FREC:
DL-Ku:
CAN:
MPEG-2 TS
Figure 40.- DVB-S (QPSK) signals VBER measurement screen.
11/2013
II
-5 -4 -3
1781.94 MHz C/N:
5037 kHz POWER:
12382.0 MHz MER:
99 » CBER:
VBER:
-7 -6 -5
1781.94 MHz C/N:
5037 kHz POTEN.:
12382.0 MHz MER:
99 CBER:
» VBER:
-2 -1
0.2 dB
51.5 dBµV
10.9 dB
9.7E-4
5.2E-8
QEF -3
0.2 dB
51.5 dBµV
10.9 dB
9.7E-4
5.2E-8
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