Viavi T-BERD 5800, Руководство пользователя

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Chapter 3 High Accuracy Timing
Configuring the module
T-BERD/MTS/SC Timing Expansion Module User Manual
Page 30 22112315, Rev. 004 July 2017
4 In Sync Source , select the synchronization source to be used to tune the TEM
Module’s rubidium oscillator.
– If you want the module to use GNSS timing, verify that you have connected a
GNSS antenna (see
“Connecting a GNSS antenna” on page 10 ), then select
Internal GNSS .
– If you want the oscillator to tune to an external 1PPS reference clock, select
External SMB 1PPS , then connect the cable providing the external 1 PPS
signal to the TEM Module connector labeled 1 PPS IN 1 .
– If you want the oscillator to tune to an external 10 MHz reference clock, select
External SMB 10M , then connect the cable providing the external 10 MHz
signal to the TEM Module connector labeled 10 MHz REF IN .
– If you want the oscillator to tune to an accurate external BITS/SETS clock,
select
External 5800 BITS/SETS , then connect the cable providing the clock
to the EXT CLK connector on the connector panel of the 5800v2 test instru-
ment.
5 In Oscillator On at Startup do the following:
– If you want the oscillator to turn on automatically when the test instrument is
turned on (and start to warm up immediately), select the checkbox.
– If you do not want the oscillator to turn on automatically when the test instru-
ment is turned on, clear the checkbox.
6 In Holdover Drift Allowed (ns) , specify the maximum acceptable drift allowed
while operating the module in holdover mode (in nanoseconds). The module will
then estimate the time remaining before the oscillator drifts to an unacceptable
level, and provide the time remaining in the Oscillator results category. For details,
see
“Oscillator Results” on page 58 .
The oscillator and timing settings are specified. If the oscillator is ON, and you specified
an external synchronization source, the oscillator will begin to tune to the frequency of
the source as soon as the cable providing the reference signal is connected to the TEM
Module. LEDs indicating that a signal is present and frequency is valid will also illumi-
nate (for details, see
“Oscillator LEDs” on page 50 ).
If you specified Internal GNSS as the synchronization source, proceed to “Specifying
GNSS settings” on page 30 .
Specifying GNSS settings
If you are using GNSS timing as your synchronization source, you must specify settings
that indicate which type of satellite system (or systems) to be used, whether you want
to use SBAS to augment the information that is provided by the satellite(s), and details
concerning the time, antenna, and elevation.
To specify GNSS settings
1 Select the Timing Module tab, then select the Setup soft key.
The GNSS setup tab appears.