Spectrum Analyzer Mode
R&S
®
Spectrum Rider FPH
151
User Manual 1321.1011.02 ─ 11
6 = Threshold line (blue line)
7 = Trace
8 = Markers
9 = AM modulation depth softkey menu
By default, delta marker 2 is active for editing. If you move the delta marker to another
position, the other delta marker will be moved by the same distance relative to the nor-
mal marker. Note that this happens only if you move delta marker 2 (D2). When mov-
ing delta marker 3 (D3), only this marker is repositioned.
From the values of the markers, the R&S Spectrum Rider then calculates the AM mod-
ulation 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 Spectrum Rider uses the mean value of the two sideband
values.
If the R&S Spectrum Rider is unable to find any AM modulated carriers, it shows the
message:
6.1.8.1
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 Spectrum Rider will not set the
markers and therefore will not calculate the modulation depth.
1. Press [MEAS] key.
2. Select "Threshold" softkey.
The R&S Spectrum Rider opens an input field to set the threshold.
3. Enter the threshold value you need.
The threshold is represented as a horizontal blue line in the diagram area.
6.1.8.2
Optimizing the Settings
To get the best results, you can use the automatic adjustment routine that the R&S
Spectrum Rider offers.
1. Press [MEAS] key.
2. Select "Adjust Setting" softkey.
The R&S Spectrum Rider performs a sweep and repeats the peak search
sequence for the three markers.
Performing Spectrum Measurements
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