Promax Promax TV EXPLORER HD ISDB-Tb, Manual

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USER’S MANUAL. TV EXPLORER HD ISDB-T/T
B
11/2010 Page 43
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Figure 20.- Screen of measurement configuration ( QAM Annex-B signals).
5.13.3 ISDB-T/T
B
(COFDM) Digital Channel Configuration
Press the Measurements Configuration [17] key to access to the
CONFIGURATION menu and turn the rotary selector [1] to access the COFDM signals
parameters which can be defined by user and are described below:
1)
Guard Interval
The Guard Interval parameter corresponds to the dead time between symbols, its
purpose is to permit a correct detection in multi path situations. This parameter is
defined according to the symbol length: 1/4, 1/8, 1/16, 1/32. To modify its value, by
turning the rotary selector [1], place the marker over the Guard Interval field and
then press it : a menu with the available values will appear. Turning the rotary selector
[1] select the desired value and finally press it to validate.
2)
Mode
Transmission mode identification based on the separation of OFDM carrier
frequencies. In the case of Brazil, the separation of frequency must necessarily be
about 4 kHz, 2 kHz or 1 kHz, respectively for modes 1, 2 and 3. The number of
carriers varies depending on the mode, but the useful rate of each mode must
necessarily be exactly the same in all modes. To modify its value, by turning the rotary
selector [1], place the marker over the Mode field and then press it : a menu with
the available values will appear. Turning the rotary selector [1] select the desired
value and finally press it to validate.
3)
Spectral Inv.
This option enables spectral inversion to be applied to the input signal, though in the
majority of cases it should be in the OFF position (not inversion).