Frequency Counter (Markers)
When resolution bandwidth around the marker to more precisely calculate the frequency of the largest signal component at the marker.
is enabled, the VSA uses a narrowerThe Frequency Counter is enabled for a marker when the Markers Calculation tab.
check box is selected in theOnly one marker per trace may have
enabled.Frequency Counter is available only for measurement types.
andTo use the frequency counter, follow these steps:
-
Set
to . - Set Trigger Type to Freerun.
-
Disable Time Gating.
-
Start the measurement.
-
Choose a frequency domain Trace Data (Spectrum, PSD Power Spectral Density: See power spectral density., or Inst Spec).
-
Add a marker and position the marker at a peak (or right-click the trace and choose
). -
Click
. -
Select the
check box.
The Markers Window will show a line labeled (where X is the marker number) that shows the calculated frequency each time a measurement update is completed.
The VSA center frequency can be set to the value calculated by the frequency counter by clicking
.Now you can vary the frequency span to more closely examine the peak signal.
Simulation Software. works with simulated hardware, but the results are not quite as accurate as with live data from measurement hardware.
does not work with recalled traces, recorded data, or data fromFrequency Counter validity
The
readout is valid only for the configurations in the following table:
Parameter: |
Setting: |
---|---|
Measurement Type | Vector or Analog Demod |
Marker |
On |
Trigger Type |
Free run |
Time gating |
Off |
Measurement Data |
Spectrum, PSD, or instantaneous spectrum |
When the
is enabled and the conditions listed in the previous table are not met, the marker readout indicates that the frequency is not valid. Here are some examples of an invalid Frequency Counter:-
SNR Signal-to-Noise Ratio" next to the frequency estimate.
: When Frequency Counter is on, the VSA estimates the length of the data block required to calculate the frequency. If the signal-to-noise ratio is very low, or the frequency span is very narrow, the VSA will be unable to accurately estimate the frequency. In this case, the Frequency Counter readout shows "Low -
¾for example, Auto Correlation¾the readout displays "Not a valid measurement."
: The Frequency Counter counts only data from the current input spectrum. If a trace data is selected that is not linked to the input spectrum - Simulation Software, the readout shows "Trace data not countable." : If the Frequency Counter is enabled for a marker on recalled traces, recorded data, data register contents, or data from
See Also