Operation instructions | SKT 40-0x | SKT 80-0x | SKT 40-0xM | SKT 80-0xM
22 2017-01-26 | Technical changes, design modifications, errors and misprints are subject to change without prior notice.
3.5.
Initialization phase 3
In phase 3, the modulators are configured.
After assigning programmes to the modulator the fill level has to be conntrolled. With the parameters of the
modulator, the datarate can in certain circumstances be reduced.
3.5.1.
Configuration of the modulator
Norm:
In this selection field, you can set the norm for the output channel spacing in
the output channel window.
Output channel:
The first modulator can be set to any output channel between S2 and CH 69.
The other three modulators are automatically set by incrementing the output
channels in accordance with the chosen channel spacing.
For
example: modulator
1
=
Channel
21
modulators 2, 3 and 4
= Channels 22, 23 and 24
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
programmes 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.
