Initialization Phase 3 - Dvb-T; Configuration Of The Modulator - axing MK 8-00 Betriebsanleitung

Operation instructions | MK 8-00 | MK 16-00 | MK 8-06 | MK 16-06
3.6. Initialization phase 3 – DVB-T
Note: Depending on the modulation standard the signals are modulated into DVB-C or DVB-T (see 3.7.2 on
page 33).
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.
3.6.1.

Configuration of the modulator

Norm:
Output channel:
Common Output level
DVB-T modulation:
28
In this selection field, you can set the norm for the output channel spacing.
Note: Changing the norm works now according to following rules:
CCIR-->Australia : all modulators forced to 7MHz
Australia-->CCIR : all modulators forced to 8MHz, however with following
exception: low channels S2-S20 are 7MHz only, so those remain in 7MHz
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
modulators 2, 3 and 4
The Common Output Level option include a general attenuation of all
modulator outputs. The highest output level is reached with a setting of 20 dB,
the lowest level with a setting of 0 dB.
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.
2019-06-15 | Technical improvements, changes in design, printing- and other errors expected.
= Channel 21
= Channels 22, 23 and 24