Kathrein UFO 331/TP Mode D'emploi page 21

1.9 Selecting the COFDM mode
The COFDM mode of the output signal is selected using the "<" and ">" buttons.
A 1236
27.500 MS/s
Outp. S21
8 MHz
Main menu
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
(see Table 1 in Chapter 4.1).
1.10 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.
Pressing the "Sub-menu" button
The modes are selected using the "<" and ">" buttons and adjusted using the "+" and "-" buttons.
A 1236
27.500 MS/s
Outp. S21
8 MHz
Main menu
The following settings are available:
Mode SAT-Sig
PRBS
CW
Outp. S21
8 MHz
Main menu (display in PRBS mode)
MHz TP
3/4 QPSK
306.00 MHz
QAM64
activates the sub-menu; pressing the "Sub-menu" button
MHz TP
3/4 QPSK
306.00 MHz
QAM64
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
PRBS
306.00 MHz
QAM64
!
***
Mode
Guard
! Code rate
***
Mode
Guard
! Code rate
"COFDM mode" sub-menu (for setting the PRBS)
7 / 14
again deactivates it.
UFO331TP
SAT Sig
1/32
5/6
Sub-menu for "COFDM modes"
UFO331TP
PRBS
1/32
5/6
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