Spectra Precision ProFlex 800 Reference Manual - Manual (Page 52)

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Receiver Description
• Active edge, i.e. the edge (falling or rising) synchronized
with GPS time. (On the diagram above, the rising edge was
set to be the active edge)
You can read the current properties of the 1PPS output using
the $PASHR,PPS command.
The signal specifications for the 1PPS output are the
following:
• Signal level: 0-5 V
• Pulse duration: 1 ms
• Jitter: < 100 ns
• Slope transient time: < 20 ns
You can also output the exact GPS time of the active edge of
the 1PPS output signal using the $PASHR,PTT command.
The receiver will respond to this command right after the next
1PPS signal is issued, taking into account the chosen offset.
Event Marker Input
This input is used to time-tag external events. When an
external event is detected on this input, the corresponding
GPS time for this event is output as a $PASHR,TTT message
on port B. The time tag provided in the message represents
the exact GPS time of the event to within 1 μsecond.
Obviously, a single message is output for each new event.
Using the Event Marker input is a standard feature of the
receiver (no firmware option needed).
The event marker input is located on port B, pin 7.
You can choose whether it will be the rising or falling edge of
the event marker signal that will trigger the time tagging of
the event. This choice can be done using the $PASHS,PHE
command.
1PPS with
Offset= 0
GPS time
1PPS with
Offset= - x.x sec
1PPS with
Offset= + x.x sec
+
_