Dvb-S/S2 Signals - Promax TV EXPLORER HD ISDB-T/T B Manual De Instrucciones

USER'S MANUAL TV EXPLORER
5.14.7.4

DVB-S/S2 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.
Figure 38.- DVB-S (QPSK) signals CBER measurement screen.
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), after Viterbi
(VBER).
Figure 39.- Digital reception system via satellite. (DVB-S).
Figure 40.- DVB-S (QPSK) signals VBER measurement screen.
10/2012
HD ISDB-T/T
B
Page 63