The PROMAX-26 will show a screen like the following figure. This screen
features the constellation diagram, the QAM modulation type, the symbol rate (SR), the
channel bandwitdh (BW), the DVB system (ITU), the bit error rate (BER) generated and
the modulation error ratio (MER) measured (see Appendix G 'Measurement the
modulation error ratio (MER) for digital channels'). These parameters, with the
exception of the two last, are modifiable from the measurement screen.
In the display lower selection box appears which quadrant is represented (in
this case is showed a graphical representation based on four quadrants, i.e. "ALL").
Figure 25.- Representation of the Constellation Diagram and BER & MER
When the
QUADR [F5] key is repeatedly pressed, the transition is made to
each single quadrant: Q1, Q2, Q3 and Q4.
4.2.4.1
SCAN / SPECTRUM function
The SCAN function shows the level of each of the active channels in the
channel plan through a floating marker on the screen. Furthermore it allows the
spectrum
graphical
SPECTRUM [F1] option from the lower selection box. Therefore will be possible to
visualise all existing interferences into the channel or adjacent channels.
Page 36
measurements of a digital channel.
analysis
with
the
USER'S MANUAL. PROMAX-26
best
resolution
when
activating
the
02/2007