DOC 6501_Release V
ATS-6501 Users Guide
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[steering]
[source] gps
[timescale]
[kas2]
[avgfiltermax] 0
[tsepoch] 0
[tsfiltermax] 2
[tsfilterref] N/A
[tsinterval] 3600
[tstimeconstant] 10800
[OK] 2013-08-05T17:22:04Z
If these settings are correct type
save
to save the proper reference and reference type in the default
user configuration file on the system to ensure the system starts up properly after a reboot or
power cycle.
Caution:
Users should allow the external frequency reference to free run and should not
manually enter corrections/adjustments into the clock. The ATS-6501 characterizes the clock’s
frequency relative to GPS and manual/user adjustment of the clock frequency may cause the
ATS-6501 outputs to not meet specification following the adjustment.
WARNING:
After replacing an external frequency reference, the
restart --cold
command must
be executed on the ATS-6501 by the operator to reset the KAS2 steering algorithm. If not, the
ATS-6501 outputs may not remain within specifications and it could take up to 9 days for the
system to provide outputs within specifications.
2.8 Using the Time Scale Reference
The timescale function can be used if a 4393 module is available and 2 or more clock’s 1 PPS
signals are input to the module. When timescale is selected the system uses the ensemble of
clocks plugged into the 4393 1 PPS measurement module as the frequency reference enhancing
timing performance and system redundancy. Clocks must be added via the 'add_clock' command
and the timescale filter reference must be set before the timescale will function.
The time scale reference setting utilizes the 1 PPS measurements from the 4393 module to create
an internal coordinated time scale (CTS) which steers the OCXO to the ensemble of clocks
connected to the 4393 module. The CTS is then steered to UTC to utilize the long term stability
of GPS. To set up the system to use the time scale as the reference, operators will need at least
two clocks to participate in the ensemble. Settings nodes are added by the user to represent each
clock in the ensemble using the
add_clock
command. These nodes are organized by a unique
name
that is chosen by the user. The operator will have to specify the clock
type
which
determines most of the physical characteristics of the clock (the noise spectral densities, etc.), the
module slot and port number, and the clock status communication protocol if monitoring is
available. For instance, possible clock types might include “hp5071” and “maser”.
At a minimum adding a clock requires selection of the name, the clock type, and the module Slot
# and Port #to which the clock’s 1 PPS is connected.
add_clock Test1 --type cesium --slot 4 --port 1
add_clock Test2 --type cesium --slot 4 --port 1
Users can specify a formal
identification
string which is typically the clocks serial number.