Chapter 13 - Constellation diagram 101
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13.2
Operation
As has already been mentioned, the constellation diagram can be displayed with all digital
standards (DVB-C, DVB-T, DVB-T2, DTMB and DOCSIS). The measuring receiver first has to be
tuned in a digital range. Subsequently the constellation diagram can be activated by selecting the
menu item
CONST
. At the same time a sub-menu is opened which makes it possible to call up
further functions.
Figure 13-1 Constellation diagram DVB-T2 zoom
By selecting the menu item
FREEZE
the diagram can be frozen. By selecting
ZOOM
another
menu appears in which each individual quadrant of the constellation diagram can be enlarged to
the full screen size. The screen layout in the
ZOOM
mode is a bit slower than in the full screen
mode due to the serial reading of the I/Q data. Thus, in case of DTMB there is no
ZOOM
mode
available.
13.3
Examples
The figures below show images of constellation diagrams. In addition possible errors and their
causes will be addressed.
Figure 13-2 Ideal constellation diagram