OPU-1
UNIVERSAL POWER-LINE CARRIER SYSTEM TYPE OPU-1
GENERAL DESCRIPTION - Rev 7 (May 2019)
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This symbol stream is first processed by a staggering block, which outputs a complex
symbol stream at twice the input rate.
This stream is then multiplied by a carrier specific exponential weight and processed by an
IFFT block, whose output is filtered by the polyphase components of the prototype pulse
followed by a decimate-and-sum network.
At the receiving side, the inverse operations are carried out.
3.4
LINK SYNCHRONIZATION
With the analog channels (MOPU module), it is possible to work plesiochronously, that is to
say, each terminal works with its own master clock or in a synchronized way, that is to say,
each terminal uses its internal oscillator as the master transmission clock and synchronizes
its reception with the other terminal using the pilot received. This synchronization is
completely digital.
The MQPU module (QAM digital channel) works with only one clock, which is internal. The
programming of the terminal configuration automatically determines a
Master-Slave
operating mode for the recovery of synchronisms. The
Master
terminal generates the
transmit synchronisms from the internal oscillator. The
Slave
terminal always uses the clock
recovered from the data received from the line to generate the transmit synchronisms. The
receive synchronisms are always generated from the clock recovered from the received
data.
With respect to synchronism, it is recommended that the customer terminals of a link use
the clocks generated in transmission and in reception by the OPU-1 terminals.
3.5
TIME SYNCHRONIZATION
The OPU-1 terminal chronologically registers all the alarms produced in the terminal, as
well as the events that refer to the link service.
In order to establish the date and time the
alarms and/or events are produced, the OPU-1 terminal has a real time clock, which can be
synchronized with the GPS system or by means of the SNTP protocol.
