Agilent Technologies Signal Analyzer N9030a - Manual (Page 725)

6 RLC Swept SA Measurement Front-Panel & SCPI Reference
Marker
5. If the reference marker is not a fixed marker, the display shows the difference between the
count of the selected marker and the count of the reference marker
6. If the reference marker is a fixed marker and there is a count stored in the marker (because
Marker Count was on when the marker became a fixed marker), the display shows the
difference between the count at the marker and the count stored in the reference marker.
Marker Count works in zero span as well as in Swept SA. The instrument tunes to the frequency
of the selected marker, which, for active zero span traces, is simply the center frequency of the
analyzer.
Fixed Markers
Fixed markers have a count stored in them that is generally kept fixed and not updated. If a fixed
marker is selected, or used as a reference, the signal at the marker frequency is not counted;
rather the stored count is seen or used as the reference. The count is stored, if Count is on, when
the marker becomes fixed or when, while fixed, the marker is moved by re-zeroing the reference (if
it is the reference marker) or via a peak search (since both of these, by definition, use valid trace
data). The count stored in a Fixed marker is lost if the counter is turned off, if the marker is
moved to an inactive trace, or if the marker is moved by adjusting its x-value.
More Information on "Counter"
When the counter is on, the count (or the delta count) for the selected marker is displayed.
The invalid data indicator (*) will turn on until the completion of the first count.
Marker Count frequency readings are corrected using the Freq Offset function (in some previous
analyzers, they were not). Note however that Marker Delta readings are not corrected, as any
offset would be applied to both.
In zero span on active traces the counter continues to function, counting any signal near the
center frequency of the analyzer.
No signal farther from the marker frequency than the Res BW will be seen by the counter.
The above command turns on or off the frequency counter. If the specified marker number in the
command is not the selected marker, it becomes the selected marker. If the specified marker
number is not on, FCOunt ON sets it to Normal and places it at center of screen on the trace
determined by the Marker Trace rules. Once the marker count is on, it is on for any selected
marker, not just for the one used in the command. A 1 is returned to the state query only if
marker count is on and the specified number is the selected marker. The invalid data indicator
(*) will turn on until the completion of the first count but this does not keep a value from being
returned.
Remote Language Compatibility Measurement Application Reference 725