Jackson Labs Micro-JLT GNSS, Руководство пользователя

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Micro-JLT GNSS™ User Manual
34 © 2019 Jackson Labs Technologies, Inc.
PTIMe:STAMp:SOURce EXT
The following command will query the state of the PTIMe:STAMp:SOURce command:
PTIMe:STAMp:SOURce?
3.5.14 PTIMe:STAMp:DIFFer <ALL|EXT|GPS>
The PTIMe:STAMp:DIFFer command is unrelated to OCXO disciplining. For more information on
OCXO disciplining, please refer to Section
3.6 .
This command selects the PPS offset source to print when the PTIMe:STAMp:MODE DIFF com-
mand from Section
3.5.12 is selected. The default offset source is set to EXT. When EXT is the off-
set source, only the external time-stamp offset will be printed. If the GPS setting is selected, only the
GPS time-stamp offset will be printed. If the ALL setting is selected, both GPS and EXT time-stamp
offsets will be printed.
The following command will query the state of the PTIMe:STAMp:DIFFer command:
PTIMe:STAMp:DIFFer?
Below is an example of the results displayed for the PTIMe:STAMp:DIFF ALL command:
EXT Offset: 266 ns
GPS Offset: 5 ns
3.5.15 PTIMe:STAMp:FILTer [OFF | REL | DUR | PPS]
The PTIMe:STAMp:FILTer command is unrelated to OCXO disciplining. For more information on
OCXO disciplining, please refer to Section
3.6 .
This command enables or disables the time-stamping filter. If any filter is enabled, the board will fil-
ter out matching time-stamps based on the type of filter. By default, the filter is in OFF mode which
the filter is disabled allowing all time-stamps to be processed. Multiple filters can be enabled at onc
except the OFF mode such as PTIMe:STAMp:FILTer REL DUR PPS command.
With the REL filter, the unit will compare the time-stamp of the incoming pulse against the average
time-stamp of GPS 1PPS. If the incoming pulse arrives outside of the GPS 1PPS time window of +/-
500 ns, the incoming pulse will be ignored without storing. When enabling the REL filter, the unit
will automatically enable the GPS 1PPS source for time-stamping. This filter is useful to filter out
spurious pulses in an external PPS source while keeping the UTC/GPS time aligned 1PPS signal.
Below is an example of the results displayed for the PTIMe:STAMp:FILT REL command. A timing
diagram for this example can be found in
Figure 3.3 .
GPS Average time-stamp: 2060, 168899.000000012 (the base comparison value)
GPS time-stamp: 2060, 168899.000000038 (this incoming pulse is kept)
EXT time-stamp: 2060, 168899.000000600 (this incoming pulse is filtered out)
If the DUR filter is enabled, the unit will compare the time-stamp of the incoming pulse to the
time-stamp of the last arrived pulse of the same source. If the elapsed time between the incoming
pulse and the last received pulse is less than 500ns of the same second, the incoming pulse will be
ignored.
Below is an example of the results displayed for the PTIMe:STAMp:FILT DUR command. A timing