Constellation Diagram; Dvb-T/H (Cofdm) Signal - Promax TV EXPLORER HD Manual De Usuario

USER'S MANUAL. TV EXPLORER HD

5.14 Constellation Diagram

The constellation diagram is a graphic representation, of the digital symbols
recived over a period of time.
There are different types of constellation diagrams for the different modulation
modes. With the TV EXPLORER
DVB-C, DVB-S and DVB-S2 signals.
In the case of an ideal trnasmission channel, free of noise and interferences, all
symbols are recognised by the demodulator without mistakes. In this case, they are
represented in the constellation diagram as well defined points hitting in the same area
forming a clear dot.
Noise and impairments cause the demodulator to not always read the symbols
correctly. In this case the hits disperse and create different shapes that at the end will
allow to determine at a glance the type of noise in the signal
Each type of modulation is represented in a different way. A 16-QAM signal is
represented on screen by a total of 16 different zones and a 64-QAM is represented by a
diagram of 64 different areas and so on.
The constellation shows in different colours the density of hits and includes
zooming, scrolling and clearing functions for a better graph representation on screen.

5.14.1 DVB-T/H (COFDM) signal

Activate the UTILITIES menu by pressing the
CONSTELLATION option. Now, on screen will be recorded the hits due to symbols
received during the digital signal transmision.
Figure 36.- Constellation Diagram. DVB-T/H (64 QAM) signal.
11/2009
HD it is possible to display constellations for DVB-T/H,
[22] key, and select the
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