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USER'S MANUAL. US TV EXPLORER II
-6
FREQ:
DL-Ku:
CH:
MPEG-2 TS
Figure 35.- 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 (CBER) and after
Viterbi (VBER).
Figure 36.- Digital reception system via satellite. (DVB-S)
-8
FREC:
DL-Ku:
CAN:
MPEG-2 TS
Figure 37.- DVB-S (QPSK) signals VBER measurement screen.
10/2007
-5
-4
-3
-2
1781.94
MHz
C/N:
0.2
5037
kHz
POWER:
51.5
12382.0
MHz
MER:
10.9
99
»
CBER:
9.7E-4
VBER:
5.2E-8
-7
-6
-5
QEF
1781.94
MHz
C/N:
0.2
5037
kHz
POTEN.:
51.5
12382.0
MHz
MER:
10.9
99
CBER:
9.7E-4
5.2E-8
»
VBER:
-1
dB
dBµV
dB
-3
dB
dBµV
dB
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