User manual
the services in the input that will not pass to
the output.
Transparent mode and processing mode
The COFDM-QAM transmodulator is able to
operate in two different modes:
- Transparent: the transport stream is not
processed.
- Processing: stuffing and PID filtering fea-
tures are available
NIT Handling
To ease receiver search of all the available
QAM channels on the SMATV network, a
NIT Table Handling mechanism has been
implemented. This consists of the genera-
ting of a NIT table that includes all the infor-
mation on the QAM channels present in the
network (frequency, modulation order, band
rate). Each trans-modulator module, QPSK-
QAM or COFDM-QAM, on entry replaces
the NIT table with this new table. In this way,
the receiver only needs to tune in to a QAM
channel to access this data, greatly easing
the search for network available services.
User management of this NIT Handling
Mechanism is carried out through a CDC
2.12 Version or better program. A detailed
description is available in the manual for this
program.
This format conversion method can also be
used to distribute DTT signals in SMATV
networks.
The
digital
transmodulator
COFDM-QAM allows the distribution in the
SMATV networks of the new services offe-
red by the DTT (video and audio high qua-
lity, subtitling, different languages, interacti-
vity...). The same IRD that is used for recei-
ving satellite trans-modulated channels is
used for receiving the signal, making it only
necessary to use one QAM IRD for receiving
both digital signals (the satellite and the
land-based one), and avoiding a drop in
quality due to trans-modulating to the ana-
log format.
DESCRIPTION OF THE PRODUCT
The COFDM-QAM transmodulator receives
a digital terrestrial channel in COFDM for-
mat, it demodulates this signal obtaining a
MPEG2 transport stream. Then this MPEG2
transport stream is modulated in QAM for-
mat and converted to RF output channel
using a agile up-converter. The different
parameters to configure the COFDM-QAM
(input channel, output channel and modula-
tion format, mainly) are programmed using
the universal programming unit (ref. 7234).
The COFDM-QAM transmodulator also
allows the preamplifiers powering through
35
COFDM QAM - TS PROC
its input. The user may choose between two
feed voltages, 12 and 24 volts, or may disa-
ble feed instead.
The mechanics of the COFDM-QAM device,
T05, permits the perfect integration with the
rest of the T-05 series range as modulators,
digital and analogue channel processors,
modulators and transmodulators (QPSK-
PAL, COFDM-PAL and QPSK-QAM). Finally
this new transmodulator, has also the
RS485 interface.