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The Spectrum Application
R&S
®
FPC
110
User Manual 1178.4130.02 ─ 07
14.6.1
Sweep Time
The sweep time (or measurement time) is the time that the analyzer requires to acquire
and analyze the data in the selected
. Large spans require more time to
measure than small spans. Generally, the R&S
FPC requires at least 20
ms for every
600
MHz of span.
In addition to the frequency span, the measurement time also depends on the selected
: smaller resolution bandwidths require more time to settle than
large ones. If the measurement time is too short, the resolution filter has no time to set-
tle. In that case, the displayed levels will be too low.
In its default state, the R&S
FPC automatically selects a measurement time that makes
sure that the measurement results for the selected span and resolution bandwidth are
correct and valid. If you change span or resolution bandwidth, the R&S
FPC adjusts
the measurement time accordingly.
In the time domain (span = 0), the R&S
FPC shows the video voltage over time. The
horizontal axis becomes a time axis that starts at 0
s and ends at the measurement
time that you have selected.
Defining the sweep time
1. Press the "Sweep" key to open the sweep menu.
2. Select one of the "Sweeptime: <x>" menu items.
● "Sweeptime: Manual"
Opens an input field to define the measurement time.
A manually selected measurement time is indicated by a blue dot in front of the
"SWT" label in the status bar.
Figure 14-13: Indicator of a manual sweep time
If you define a sweep time that is lower than the automatic sweep time, the dot
in front of the "SWT" label and the sweep time display turn red.
Figure 14-14: Indicator of a low sweep time
● "Sweeptime: Auto"
Automatically selects an appropriate measurement time depending on the cur-
rent
Tip:
When you press the "Sweep" key, the R&S
FPC automatically opens an input
field to define the sweep time. If the input field is inactive, you can open it with the
"Sweeptime: Manual" menu item.
14.6.2
Sweep Mode
The sweep mode defines how often the analyzer measures the frequency spectrum.
Sweep Configuration