Dvb-T/H (Cofdm) Signal - Promax TV EXPLORER II Manual De Instrucciones

USER'S MANUAL. TV EXPLORER II/II+
There are different types of constellation diagrams for the different modulation
modes. With the TV EXPLORER II / II+ it is possible to display constellations for
DVB-T/H, 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
Every modulation type is represented differently. A DVB-C 16-QAM signal is
represented on the screen by a total of 64 different zones 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.

5.15.1 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.
MPEG-2 TS DVB-T
Figure 41.- Constellation Diagram. DVB-T/H (QAM 64) signal.
By means of the rotary selector [1] and the arrow cursors
to change the frequency, channel or COFDM carrier on tune by the instrument.
The DECAY option sets the visual persistence for symbol impacts on the screen in
a range from 0 (minimum persistence) to 16 (maximum persistence).
12/2013
[22] key, and select the
MODULATION:
DVB-T/H (64 QAM)
F: 794.00 MHz
CH: 66
CARRIER: 0
TYPE: data
DECAY: 16
ZOOM:x1 CLEAR
[6] key, is possible
Page 61