Promax TV Explorer HD Manual De Usuario página 174

USER'S MANUAL. TV EXPLORER HD / HD
LE
Figure 34.- 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, after Viterbi (VBER).
Figure 35.- Digital reception system via satellite. (DVB-S)
Figure 36.- DVB-S (QPSK) signals VBER measurement screen.
Page 58 05/2011