USER’S MANUAL. TV EXPLORER II/II+
12/2013
Page
59
En
g
lis
h
Finally it is shown a status line with information about the detected signal. The
possible messages that can appear and its meaning are shown in the following list. The
messages are exposed from less to more fulfilment of the
MPEG-2
standard:
No signal received
Any signal has been detected.
Signal received
A signal is detected but it can not be decoded.
Carrier recovered
A digital carrier has been detected but it can not be decoded.
Viterbi synchronized
A digital carrier has been detected and the Viterbi algorithm is synchronized, but
too many frames arrive with non correctable errors. It is not possible to quantify the
BER.
MPEG-2 TS DVB-S
Correct detection of a MPEG-2 signal.
5.14.8
Digital TV: Measuring MER
Once determined the suitable parameters for
COFDM
,
QAM,
QPSK
or
8PSK
signal reception, it will be possible to measure
MER
, press
[12] key until it appears
the
MER
measurement screen.
FREQ:
CH:
C/N:
POWER:
MER:
CBER:
VBER:
»
>21.3
55.8
19.5
dB
dBµV
dB
650.00
-3
43
5.0E-2
5.3E-4
0 10 20 30 40
NM:
8.4 dB
MHz
kHz
MPEG-2 TS DVB-T
Figure 39.-
DVB-T/H
(
COFDM
) signals
MER
measurement screen.
First of all, you will see the
modulation error ratio
measurement:
MER
.
Following, it appears the Noise Margin (
NM
) measurement (in the figure value 8.4
dB). It indicates a safety available margin according to the
MER
level measured that
allows signal degradation until arriving to the
QEF
(
Quasi
-
Error-Free
) limit value.
