Spectrum Analyzer Mode
R&S
®
Cable Rider ZPH
224
User Manual 1321.0950.02 ─ 07
width and is the same as the resolution bandwidth. If you change the resolution band-
width, the R&S Cable Rider ZPH adjusts the video bandwidth accordingly.
The effects of the video bandwidth on measurements are as follows.
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If you are performing measurements on modulated signals, the video bandwidth
must be sufficiently large so that significant modulation components are not rejec-
ted (≥ RBW)
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If you want to keep signals free of noise, you should select the smallest video
bandwidth possible (≤ 0.1 x RBW)
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If you are performing measurements on pulsed signals, the video bandwidth should
be at least three times greater than the resolution bandwidth so that the pulse
edges are not distorted
Like the resolution bandwidth, the video bandwidth has an effect on sweep speed.
Before each measurement, the video filter has to settle.
1. Press the [DTF/BW] key.
By default, the resolution bandwidth is coupled to the span.
2. Select the "Manual VBW" softkey.
The R&S Cable Rider ZPH opens an input field to define the video bandwidth.
3. Enter the video bandwidth you need.
The R&S Cable Rider ZPH uses the video bandwidth you have entered for the
measurement. If the video bandwidth is no longer coupled to the resolution band-
width, the R&S Cable Rider ZPH puts a blue dot at the "VBW" displays on the
"Parameter View".
4. Select the "Auto VBW" softkey again to couple the video bandwidth to the RBW.
8.2.6
Configuring and Triggering the Sweep
You can find all necessary settings to configure the sweep itself in the sweep menu. To
access it, press the [SWEEP] key.
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Setting the Sweep Time
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Selecting the Sweep Mode
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Working with Trigger Functionality
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8.2.6.1
Setting the Sweep Time
The sweep time is the time it takes the R&S Cable Rider ZPH to get the results that are
contained in one trace.
In the frequency domain (span > 0), the sweep time is the time it takes the R&S Cable
Rider ZPH to measure the spectrum in the specified span. To avoid the display of
spurs in the spectrum, the sweep time has to meet some conditions.
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The sweep time depends on the resolution bandwidth. If the sweep time is too
short, the resolution filter has no time to settle. In that case, the displayed level is
Configuring Spectrum Measurements
