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TV EXPLORER HD / HD
USER'S MANUAL.
With the aim to have a reference about the signal quality, it is considered that a
system has a good quality when it decodes less than one non-correctable error for every
transmission hour. This border is known as
approximately to a BER before FEC of
bits of every 10,000). This value is marked on the measurement bar of the
BER
therefore,
for acceptable signals must be at the
BER
Below the
analogue bar it is shown the tuned frequency (or channel) and the
frequency deviation in kHz between the tuned frequency and the one, which optimizes
the BER (i.e. 800.00 MHz + 1.2 kHz). This deviation must be adjusted specially from the
C/N
measurement in satellite band, by tuning again the channel in frequency mode
[24], to the lower reachable value.
5.14.7.2 DVB-T/H signals
Once determined the parameters of
BER
.
Two types of measurements appear:
Following is shown the BER measurement before the error corrections:
before the FEC
CBER
:
Figure 31.- DVB-T/H
In a reception system of terrestrial digital signal, after the
error correction methods are applied. Obviously, each time we apply an error corrector to
the digital signal, the error rate changes, therefore if we measure the error rate at the
COFDM
output of the
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. The
TV EXPLORER
HD
/
HD
10/2012
LE
QEF
2.0E-4 BER
COFDM
.
COFDM
(
) signals
BER after Viterbi (VBER
provides the
LE
Quasi-Error-Free
(
) and it corresponds
(2.0x10
-4
, that is to say two incorrect
left
side of this mark.
signal, it will be possible to measure
CBER
measurement screen.
COFDM
).
BER
and
BER
decoder two
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