USER’S MANUAL. PROMAX-10
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4.2.3.1.5
Constellation Diagram representation, Bit Error Rate (BER)
and Modulation Error Ratio (MER) measurement in digital
channels.
Once obtained the Power and C/N ratio measurement, the BER and MER
measurement on tuned channel as well as the Constellation Diagram graph
representation for the DVB-QAM digital signal can be obtained pressing the rotary selector
. (See appendix H 'Principle of QAM modulation. The Constellation Diagram').
The PROMAX-10
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, after some seconds for calculation, will show a
screen like the one of the attached figure. On it besides the Constellation diagram,
also appears the type of QAM modulation, the symbol rate (SR), the error rate obtained
for the digital signal (BER), the modulation error ratio measurement (MER) (see
appendix G 'Measurement of the modulation digital ratio (MER)'), the represented
quadrants (Q1-4) and the type of detected codification (MPEG2).
When pressing again the rotary selector
, the PROMAX-10
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carries out a new measurement. If the selector rotary is pressed two times, it is acceded
again to the screen of Power and C/N ratio measurement (section 4.2.3.1.4).
Figure 21.- Constellation Diagram representation and
BER and MER measurement in a digital channel.
When pressing the CH-FR [10] from Q1-4 (graphical representation in four
quadrants), goes to only a quadrant e.g.: Q1, pressing again CH-FR [10] obtains an
extended representation (zooming x4) e.g.: Q1 Z. Press CH-FR [10] to return afresh to the
Q1-4 mode.
In order to change the quadrant, from Q1-4 press and keep pressed the CH-FR
[10] key until a quadrant frame selector will appear and slide it by means of the rotary
selector [9], locate it in the wished quadrant and finally loose the CH-FR [10] to set the
new quadrant for representing.
4.2.3.1.6
Configuration of QAM signal measurement using edit
channel plan.
From the edit channel plan it’s possible to access directly to the following page
of the configuration menu of the parameters relative to this mode, for the tuned channel.
