Common Measurement Settings
R&S
®
FSW
407
User Manual 1173.9411.02 ─ 19
Normal (3dB) Gaussian filters
Gaussian filters provide a good compromise between steep edges and a short settling
time. This filter is suitable for most measurement tasks and is used by default.
The available Gaussian (3dB) sweep filters are listed in the R&S
FSW data sheet.
Channel filters
Channel filters are fairly steep but require a long settling time; they are useful for pulse
measurements in the time domain.
RRC filters
Root raised cosine filters are similar in shape to channel filters and are required by
some measurement standards.
5-Pole filters
5-Pole filters are very broad and allow for a large bandwidth to pass.
6.5.1.7
How Long the Data is Measured: Sweep Time
Each filter has a settling time that must be awaited in order to obtain correct results.
Since the resolution bandwidth and video bandwidth define the filter, the smaller of the
two determines the minimum sweep time required for the measurement. Allowed val-
ues depend on the ratio of span to RBW and RBW to VBW.
If the selected sweep time is too short for the selected bandwidth and span, level mea-
surement errors will occur. In this case, the R&S
FSW displays the error message
"Sweep time too low" and marks the indicated sweep time with a red bullet. Further-
more, a status bit indicates an error (see
"STATus:QUEStionable:TIMe Register"
The sweep time can be coupled to the span (not zero span), video bandwidth (VBW)
and resolution bandwidth (RBW) automatically. If the span, resolution bandwidth or
video bandwidth is changed, the sweep time is automatically adjusted.
6.5.1.8
How Much Data is Measured: Sweep Points and Sweep Count
By default, 1001 data points are determined in a single sweep. During the next sweep,
1001 new data points are collected, and so on. The number of
sweep points
defines
how much of the entire span is covered by a single data point. By increasing the num-
ber of sweep points you can increase the reliability of the individual data points and
thus the accuracy of the analyzed results. However, these data points are all stored on
the instrument, occupying a large amount of memory, and each sweep point increases
the overall measurement time. Up to 200 000 points can be swept at once.
The number of sweeps to be performed in single sweep mode is defined by the
"Sweep Count". Values from 0 to 200000 are allowed. If the values 0 or 1 are set, one
sweep is performed. The sweep count is applied to all the traces in a diagram.
Bandwidth, Filter and Sweep Configuration
