Dvb-T (Cofdm) Digital Channel Configuration - Promax PRODIG-5 Manual Del Usuario

USER'S MANUAL. PRODIG-5

5.13.2 DVB-T (COFDM) Digital Channel Configuration

Press the Measurements Configuration
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) Carriers (Number of carriers)
It defines the number of modulation carriers between 2k and 8k. To modify its
value, place the marker over the Carriers field by turning the rotary selector and
then press it: a menu will appear on the screen. Turning the rotary selector [1]
select the desired value for the Carriers parameter and finally press it again to
validate.
2) 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.
3) Channel BW (channel bandwidth)
Enables the channel bandwidth to be selected between 8 MHz, 7 MHz and 6
MHz. The selection of this parameter is essential for the correct operation of the
tuner, as it affects the frequency separation of the carriers.
4) Spectral Inv. (spectral inversion)
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).
This configuration menu shows, besides the user definable COFDM signal
parameters, the value of the rest of signal parameters detected automatically:
Code Rate Also known as Viterbi ratio, defines the ratio between the data bits
number and the total number of bits transmitted (the difference
corresponds to the number of control bits for the error detection and
recovery).
Modulations Carriers modulation. It also defines the system noise immunity.
(QPSK, 16-QAM and 64-QAM).
Hierarchy The DVB-T norm contemplates the possibility to make a TDT
transmission with hierarchical levels, it is to say a simultaneous
transmission of the same program with different image qualities and
noise protection levels, in order the receiver can exchange to a
signal of smaller quality when the reception conditions are not
optimal.
11/2013
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