Promax PROLINK-4/4C Premium Manual De Instrucciones página 166

Terrestrial band - Digital channels:
Channel power
C/N
DVB-C
DVB-T
Page 30
Auto: In-channel measurement. Noise level is measured at
a frequency where modulation contents is minimum. After a
small period of time, minimum measured level corresponds
to noise level.
The equivalent noise power measurement is carried out by
means of a patented procedure of statistical stimation.
Referenced: The user defines the frequency where noise
level will be measured (by means of the Reference noise
function). This frequency will be used to measure noise
level for all channels.
Automatic method: channel power is measured assuming
that power spectral density is uniform throughout channel
bandwidth. To measure it correctly it is indispensable to
define the Channel BW.
Two methods selectable through the C/N setup function:
Auto: Out-channel measurement. Noise level is measured
at f noise = f tuning - ½*Channel BW. To measure it correctly
digital channel must be tuned at its central frequency.
Referenced: The user defines the frequency where noise
level will be measured (by means of the Reference noise
function). This frequency will be used to measure noise
level for all channels.
Obtains the error rate for the signal found in the tuned
channel. After processing for a few seconds, the screen on
the PROLINK-4/4C
modulation, the MER (modulation error ratio), and the BER
(error rate) for the digital signal before error correction (BER
before FEC), the latter two are shown in analogue form as
a bar graph. The instrument also shows the channel or
frequency with the corresponding deviation, the number of
wrong packets received during the measurement time
(W.P.) and information on the type of digital Multiplex
detected (MPEG2, Network, Provider, Bouquet) which
appears cyclically on the screen.
Obtains the error rate for the signal found in the tuned
channel. After processing for a few seconds, the screen on
the PROLINK-4/4C
modulation, the CSI (Channel Status Information) or the
MER measurement (modulation error ratio) selectable by
means of the option COFDM Setup from functions menu,
as well as the BER (error rate) for the digital signal after
error correction (BER after Viterbi), the latter two are
shown in analogue form as a bar graph. The instrument
USER'S MANUAL. PROLINK-4/4C
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06/2005