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R&S FSH
Spectrum Analyzer Mode
Performing Spectrum Measurements
Operating Manual 1173.6275.12 - 30
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From the values of the markers, the R&S FSH then calculates the AM modulation
depth. The AM modulation depth is the ratio between the power values at the
reference marker and at the delta markers. When the powers of the two AM side bands
are not the same, the R&S FSH uses the mean value of the two sideband values.
If the R&S FSH is unable to find any AM modulated a carriers, it shows the message
.
3.1.8.1 Setting a Threshold
You can set a threshold that defines the minimum power level the signal must have. If
the power of the signal is below the threshold, the R&S FSH will not set the markers
and therefore will not calculate the modulation depth.
► Press the MEAS key.
► Press the "Threshold" softkey
The R&S FSH opens an input field to set the threshold.
► Enter the threshold value you need.
The threshold is represented as a horizontal blue line in the diagram area.
3.1.8.2 Optimizing the Settings
In order to get the best results, you can use the automatic adjustment routine that the
R&S FSH offers.
► Press the MEAS key.
► Press the "Adjust Settings" softkey.
The R&S FSH performs a sweep and repeats the peak search sequence for the
three markers.
3.1.8.3 Activating the Marker List
To see the exact frequency of the carrier and its sidebands, you can activate the
marker list that shows the value for each marker.
► Press the MKR key.
► Press the "View List" softkey.
The R&S FSH displays the marker list that contains the values for carrier and
sideband.