Kathrein DVB-S(2)-COFDM Manual Del Usuario página 21

1.10 Selecting the COFDM mode
The COFDM mode of the output signal is selected using the "<" and ">" buttons.
E1 1236
27.500 MS/s
Outp. S21
8 MHz
Use the "+" or "-" keys to set the modulation type of the COFDM carriers to the values QPSK, QAM16, or QAM64 defi ned in the
DVB-T specifi cation.
Note: Since the possible output data rate for COFDM-modulated signals is normally lower than the input data rate,
it is recommended to use the highest QAM stage (QAM64) if possible. The lower QAM stages QAM16 and
QPSK offer a higher interference resistance but a lower transmissible data rate. Table 1 in the appendix shows
the connection between modulation type, code rate, guard interval and the possible maximum data rate.
1.11 Selecting the operating mode for the COFDM
modulator
In the sub-menu of the COFDM mode you can select the operating mode (source signal) for the COFDM modulator.
Press the "Sub-menu" button
The modes are selected using the "<" and ">" buttons and adjusted using the "+" and "-" buttons.
E1 1236
27.500 MS/s
Outp. S21
8 MHz
The following settings are available:
Mode SAT-Sig
PRBS
CW
Outp. S21
MHz
8
Main menu (display in PRBS mode)
MHz
3/4
306.00
QAM64
Main Menu
to activate the sub-menu; press the "Sub-menu" button
MHz
3/4
306.00
QAM64
Main Menu
Normal mode,
the SAT input signal is transmodulated, in the case of input signal interferences only full
bytes (0xFF) are modulated
Test mode: the COFDM signal is modulated with a PRBS-23 sequence, normal mode is not
available in this setting
Test mode: sine wave signal for levelling using simple measurement devices, normal mode is not
available in this setting
306.00
QAM64
TP
QPSK
MHz
TP ***
QPSK Mode
MHz Guard
Code rate
***
PRBS
Mode
MHz Guard
Code rate
"COFDM mode" sub-menu (for setting the PRBS)
7 / 14
again to deactivate it.
UFO333MX
SAT Sig
1/32
5/6
Sub-menu for "COFDM modes"
UFO333MX
PRBS
1/32
5/6
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