M
ULTI
-S
OURCE
S
YSTEM
- G
ENERAL
Multi-Source Function System 7001RC - V02.01
9 / 31
hopf
Elektronik GmbH
Nottebohmstr. 41 • D-58511 Lüdenscheid • Tel.: +49 (0)2351 9386-86 • Fax: +49 (0)2351 9386-93 • Internet: http://www.hopf.com • E-Mail: [email protected]
1.2.4 Leap Second
There are time transfer formats that carry out a leap second changeover with or without an
announcement.
In the case of a leap second changeover without an announcement the time leaps by one
second, without the receiver being able to prepare for this. Since the time output is always
prepared in advance, other sub-systems that are synchronised by the receiver cannot accept
the leap second changeover and therefore continue to operate with an incorrect time until
the next time transfer.
1.2.5 Automatic / Manual Changeover between the Sync. Sources
•
Multi-source with
automatic
changeover between the sync. sources:
The system automatically selects the sync. source, depending on the
synchronisation status of the sync. source and the system status.
•
Multi-source with
manual
changeover between the sync. sources:
The user can decide which sync. source should be selected to synchronise the
system. In the event of failure of this sync. source there is no automatic switchover
to the second sync. source.
1.2.6 Time Leaps when switching between two Sync. Sources
Sync. sources may have leaps in time due to, for example
•
different signal runtimes,
•
different time base accuracies
•
configuration errors
•
time differences or
•
different time offsets to UTC etc.
Since each sync. source is evaluated in its own right and its time is accepted as valid,
provided that the time signal meets the formal conditions for synchronisation of the
respective channel, there may result a time leap in the multi-source system when switching
between sync. sources.
1.2.7 Unification of the different Time Information
There are various time transfer formats that must be known to the receiver system in order
for it to be able to calculate the correct time base.
For example:
•
GPS always transmits in UTC
•
IRIG-B transmits local time as standard but can also transmit in UTC
