Promax Promax TV EXPLORER HD ISDB-Tb, Manual

Page: 177 / 206

USER’S MANUAL. TV EXPLORER HD ISDB-T/T
B
11/2010 Page 67
En
g
lis
h
5.15.2 DVB-C (QAM) signal
Sets on the UTILITIES menu by pressing the [22] key, and select the
CONSTELLATION option.
On screen appears the modulation type: DVB-C ( 256 QAM ). Also the frequency
and channel number are indicated. Finally, it shows the type of DVB-C broadcast
network used.
Figure 46.- Constellation diagram. DVB-C ( QAM 256 ) signal.
NOTE
The transmission quality is visualised in a qualitative way using a colour range for the
symbol proporcional to the density of symbols concentrated in one determined area. This
colour coding goes from black (no symbols) to red (maximum density), and runs from
blue to yelllow 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-S/S2 (QPSK/8PSK) signal
Go to the UTILITIES menu by pressing the [22] key, and then select the
CONSTELLATION option.