Operation instructions | SKT 40-00 | SKT 80-00 | 8PSK/QPSK | COFDM Quattro/Octo Module
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2016-01-11 | © AXING AG Switzerland | Subject to change in design and type; errors and misprints reserved
3.4.
Initialization phase 3
In phase 3, the modulators are configured.
The first modulator can be set to any output channel between 114 and 1,006 MHz. The other three modulators
are automatically set by incrementing the output channels in accordance with the chosen channel spacing.
For example: (Modulator 1: S21) – (modulators 2; 3; 4: S22; S23; S24)
The output channels of the four modulators must be neighbor channels and have the same HF output.
Norm:
In this selection field, you can set the norm for the output channel spacing in the output channel window.
Output channel:
The output channel of the first modulator is set in accordance with the chosen channel spacing.
DVB-T modulation:
The modulation can be set on QPSK, on QAM 16 or on QAM 64.
The QPSK-setting provides the smallest data rate to the output channel. The QPSK-modulation process is used
in bad distribution networks because of its robustness against disturbances and of its safe transmission.
The QAM-modulation process allow reaching higher data rates, so that more programs can be transmitted on a
channel. The QAM 64-modulation gives the highest data rate.
QPSK (2 bit) – small data rate – very robust signal.
QAM 16 (4 bit) - middle data rate.
QAM 64 (6 bit) - high data rate.
DVB-T FEC (forward error correction):
Thanks to the error correction, errors resulting from high-disturbed transmission routes can be balanced by
restoring data.
The data required to restore the signal are included in the transmitted FEC bits.
Changing the FEC factor modifies the part of the FEC data in relation to the application data.
