Promax TV EXPLORER HD+ Manual De Instrucciones página 185

USER'S MANUAL. TV EXPLORER HD+
Figure 37.- Screen LBER measurement COFDM modulated signals (DVB-T2).
DVB-T2 uses two error correction codes that are the LDPC (Low Density Parity
Check) in combination with the BCH (Bose-Chaudhuri - Hocquengham) to protect signal
against high levels of noise and interference. On screen, along with the measure of
LBER it is displayed the number of iterations LDPC, that is, the number of times that the
LDPC decoder for error correction has to go through the signal and the ESR (Errored
Second Ratio) over 20 seconds after the BCH decoder. This measure indicates the
percentage of time with errors after the BCH. Error correction is internal with BCH and
external with LDPC. Internal correction provides basic error correction with minimal load
while the external error correction is an additional correction with load.
The LBER measurement is provided in scientific notation (i.e. 1.0 E-8 means 1.0 x
10-8, that is to say one incorrect bit of every 100.000.000) as its value is smaller the
signal quality will be better).
Next it is shown the tuning frequency and the frequency deviation in kHz between
the tuned frequency and the one, which optimizes the LBER. (for example Freq.:
730 MHz+ 2 kHz).
Finally it is shown a status line with information about the detected signal. The
possible messages that can appear and its meaning are showing the following list. The
messages are exposed from less to more fulfilment of the MPEG-2 standard:
No signal received
No signal has been detected.
Signal received
A signal is detected but it can not be decoded.
P1 Fixed Signaling
The demodulator has found a symbol P1.
L1-PRE Fixed Signaling
The demodulator has been able to decode the signaling information L1-Pre.
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