TV Explorer HD ATSC manual - Promax

USER’S MANUAL. TV EXPLORER HD ATSCMPEG-2Correct detection of a MPEG-2 signal.5.14.7.4 DVB-S/S2 signalsOnce determined the parameters of QPSK signal, it will be possible to measureBER. Following is shown the BER measurement before the error corrections: BERbefore the FEC: CBER.EnglishFigure 38.- DVB-S (QPSK) signals CBER measurement screen.In a digital reception system for satellite signals (DVB-S), after the QPSK decodertwo different correction methods are applied (see following Figure). Obviously, each timewe apply an error corrector to a digital signal, the error rate changes, therefore if wemeasure in a digital satellite television system, for example, the error rate at the output ofthe QPSK demodulator, at the output of the Viterbi decoder, and at the output of theReed-Solomon decoder, we obtain nothing more than different error rates. This is thereason because the BER measurement is provided before FEC (CBER), after Viterbi(VBER).Figure 39.- Digital reception system via satellite. (DVB-S).03/2012 Page 61