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USER'S MANUAL. TV EXPLORER HD +
Figure 47.- Constellation Diagram. DVB-T2 (QAM 256) signal.
By means of the rotary selector
possible to change the frequency, channel or OFDM 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) to 16 (maximum).
First appears the information about the type of modulation DVB-T2 (QAM-256).
Next it is indicated the frequency, the channel and the carrier tuned. It is also indicated
the carrier type (data or pilot). Finally, it shows the status line (similar to the
measurement screen).
NOTE
The transmission quality is visualised in a qualitative way using a colour range for
the symbol density concentrated in a certain area. This colour coding goes from black
(no symbols), to red (maximum density), and runs from blue to yellow in ascending order.
A greater dispersion of the symbols indicates greater level of noise or worse signal
quality.
If concentration of symbols or noise appears is indicative of good carrier/noise
ratio or absence of problems as phase noise, etc.,.
5.15.3 DVB-C (QAM) signal
Sets on the UTILITIES menu by pressing the
CONSTELLATION option.
12/2011
[1] and the arrow cursors
[22] key, and select the
[6] key, is
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