OPU-1
UNIVERSAL POWER-LINE CARRIER SYSTEM TYPE OPU-1
GENERAL DESCRIPTION - Rev 7 (May 2019)
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MQPU.1X DIGITAL MODEM UNIT
This module includes two data ports, one for synchronous data, with interface
V.35 or V.11 or G.703, and the other for asynchronous data, with interface
V.24/V.28. It also includes an Ethernet user interface.
It contains the frequency conversion and modulation and demodulation circuits,
synchronization and automatic gain control (AGC) circuits, and the control circuits
of the optional internal multiplexer.
For QAM, it also contains the circuits for link quality measurement according to the
G.821 standard, an adaptive equalizer which minimizes the intersymbol
interference, and the echo canceller which allows the transmission in
superimposed bands to be carried out.
For processing the signals proceeding from the interfaces, this module generates
an internal frame and carries out the 128-QAM, 16-QAM or 4-QAM modulation,
and the Trellis coding.
In OFDM/OQAM, the bit stream is dynamically assigned to the 244 carriers
which can be modulated from a 4-QAM to a 4096-QAM depending on the
channel quality and sharing this modulation each group of carriers. The turbo
code rate also is dynamically assigned.
The type of module depends on the digital modulation scheme, in this way:
MQPU.10
QAM.
MQPU.11
OFDM/OQAM
RXPU
RECEPTION FILTER
This module comprises the receive-channel filter. This module is located in the
3 s.u. shelf.
HIPU
HF HYBRID
This module contains the high-frequency hybrid. This module is located in the
3 s.u. shelf.