OPU-1
UNIVERSAL POWER-LINE CARRIER SYSTEM TYPE OPU-1
GENERAL DESCRIPTION - Rev 7 (May 2019)
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When time synchronization is established in the terminal, via GPS or Ethernet, the
OPU-1 refers its internal real time clock to the UTC
(1)
system, estimating in this way the
UTC time by which it can calculate the time in other zones of the world. In this case, the
UTC time will always remain as a model of the internal clock of the terminal, even
against any date and time programming carried out by the user.
3.5.1
GPS synchronization
The OPU-1 terminal can synchronize its real time clock with the time reference given by the
GPS system. In order to do so, the time, day, month and year must be programmed in the
OPU-1 terminal and it must then be connected to a GPS receiver that has a timing output,
which must be an IRIG-B output. The IRIG-B standard establishes the format of signals
used to identify specific instants of time.
The standard IRIG-B signals are classified according to the modulation applied to them,
their frequency/resolution and codes applied to the words (set of bits) that contain the
information. According to this classification, a number is applied to each one of the three
parameters mentioned earlier and standards are defined, such as for example, the
IRIG-B 120 or the IRIG-B 123.
The OPU-1 terminal is capable of processing standard IRIG-B 123 signals, in which the
signal is modulated in amplitude at 1 kHz, and standard IRIG-B 003 signals, in which the
signal is modulated by pulses.
3.5.2
Ethernet synchronization
The OPU-1 terminal can also synchronize its real time clock via Ethernet using the SNTP
(Simple Network Time Protocol) protocol, which uses UTC as a time base.
It is possible to configure up to 5 possible addresses of SNTP servers from the OPU-1
Management System.
(1)
UTC is not really an abbreviation but a variant of universal time (
UT
) and the C of “coordinated”
is added to show that it is another variant of UT.
