R&S FSW Series, Руководство пользователя

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Common Measurement Settings
R&S
®
FSW
464 User Manual 1173.9411.02 ─ 43
Normal (3 dB) 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 (3 dB) 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.
8.5.1.7 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
values 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
measurement 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.
(For more information see "STATus:QUEStionable:TIMe Register" on page 764.)
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.
Note that the "Sweep Time" only indicates how long data is captured; the time required
to process the captured data may be considerably longer, in particular for FFT mode.
For FFT mode, an estimated duration is indicated behind the "Sweep Time" in the
channel bar (for RF measurements only).
8.5.1.8 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
Bandwidth, Filter and Sweep Configuration