ratio (in dB). The fourth column displays MER (in dB) and the fifth column will display postBER values. For
digital channels you will see «
--
»
message in the second and third columns, and for analog channels «
--
»
message in the fourth and fifth columns. If the noise measurement has been disabled for one of the analog
channels, «
--
» message will be displayed in the second column for this channel. If DVB-T demodulator
synchronization with digital channel has not been achieved during its measurement, no lock icon
will
appear in the fourth and fifth columns.
The bottom line (position 4) contains the commands that you can activate by the functional keys.
Press
or keys to select the required channel. The selection will be framed (position 2).
The list of available commands:
a)
F1
key to measure the page;
b)
F2
key to view the measurement results in SCAN measurement mode (Section 4.3.3);
c)
F3
key to view and edit the limit plan parameters.
To start page measuring, press
F1
key. Measuring process will be indicated by a progress bar. After the
measuring is completed, the new values will appear in the measurement result field of the screen. If the
channel name is highlighted in inverse color (position 3), this indicates that the errors have been detected in
this channel during the check against the limit plan. Incorrect parameters are also highlighted in inverse
color.
To identify the errors, activate the limit plan manager (
F3
key). The table of limit plan parameters will
appear on the screen (Figure 4.4.9).
Figure 4.4.9
This table represents the parameters for the measurement results to be verified with. The parameters
are editable only using a PC. The table contains 13 parameters:
a)
Lev Vid Min.
The minimum value of video carrier level for analog channel. Default value: 48 dBuV.
Available values: 45 to 95 dBuV;
b)
Lev Vid Max.
The maximum value of video carrier level for analog channel. Default value: 85 dBuV.
Available values: 45 to 95 dBuV;
c)
Lev Dig Min.
The minimum value of digital channel level. Default value: 48 dBuV. Available values: 45
to 95 dBuV;
d)
Lev Dig Max.
The maximum value of digital channel level. Default value: 85 dBuV. Available values:
45 to 95 dBuV;
e)
Video/Audio min.
The minimum value of V/A ratio. Default value: off. Available values: 5 to 20 dB;
f)
Video/Audio max.
The maximum value of V/A ratio. Default value: off. Available values: 5 to 20 dB;
g)
Video/Noise min.
The minimum value of C/N ratio. Default value: off. Available values: 15 to 55 dB;
h)
dL adjacent max.
The maximum value of ratio between the adjacent channel levels. Default value: 10
dB. Available values: 2 to 10 dB;
i)
Video/Dig max.
The maximum value of ratio between analog and digital channel levels. Default value:
25 dB. Available values: 5 to 30 dB;
j)
MER(QPSK) min.
The minimum value of MER for DVB-T channels with QPSK subcarriers
modulation. Default value: 12 dB. Available values: 2 to 35 dB;
k)
MER(QAM16) min.
The minimum value of MER for DVB-T channels with QAM16 subcarriers
modulation. Default value: 27 dB. Available values: 6 to 35 dB;
l)
MER(QAM64) min.
The minimum value of MER for DVB-T channels with QAM64 subcarriers
modulation. Default value: 30 dB. Available values: 10 to 35 dB;
m)
postBER max.
The maximum value of postBER. Default value: off. Values available: 1E-4,
1E-5,
1E-6, 1E-7, 1E-8, off. If you make off
setting, postBER parameter will not be measured when the
data log page is measured.
For editing limit plan, choose parameter you want to change with
or keys. Then tune parameter
value with
◄
and
►
keys. For swithing off parameter set the minimal parameter’s value with
◄
key. You will
see
«off»
message. Press
or
key to return to the data log page table. The channels, which failed the
20
Summary of Contents for IT-14
Page 1: ...IT 14 DVB T SIGNAL ANALYZER OPERATING MANUAL...
Page 2: ...2 22 04 2011...
