Dvb-C Signals - Promax TV EXPLORER HD ATSC Manual De Instrucciones

USER'S MANUAL. TV EXPLORER
5.14.7.2

DVB-C signals

Once determined the parameters of QAM signal, it will be possible to measure
BER, press the [12] key until the BER measurement display appears.
In the BER measurement mode, the monitor will show a display like the following
one:
Figure 33.- DVB-C (QAM) signals BER measurement screen.
The BER measurement before error correction is shown: BER before FEC
(Forward Error Correction).
In a digital reception system for cable signals, after the QAM demodulator an error
correction method called Reed-Solomon is applied (see following Figure). Obviously,
the error rate after the corrector is lower to the error rate at the QAM decoder output.
This is the reason because this screen provides the BER measurement before FEC
(Forward Error Correction).
The BER measurement is provided in scientific notation (i.e. 1.0 E-5 means
-5
1.0x10 that is to say one wrong bit of every 100000) and through an analogue bar (as
its length is smaller the signal quality will be better). The analogue representation is done
on a logarithmic scale (not linear).
12/2010
HD ATSC
Figure 34.- Digital reception system via cable.
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