Measurements
R&S
®
FSW
200
User Manual 1173.9411.02 ─ 19
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The minimum span of a range is 20 Hz.
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The individual ranges must not overlap (but may have gaps).
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The maximum number of ranges is 30 (in firmware versions < 1.60: 20 ranges).
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The minimum number of ranges is 3.
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The reference range cannot be deleted.
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The reference range has to be centered on the center frequency.
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The minimum span of the reference range is given by the current "TX Bandwidth"
(see
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Frequency values for each range have to be defined relative to the center fre-
quency.
In order to change the start frequency of the first range or the stop frequency of the last
range, select the appropriate span with the SPAN key. If you set a span that is smaller
than the overall span of the ranges, the measurement includes only the ranges that lie
within the defined span and have a minimum span of 20 Hz. The first and last ranges
are adapted to the given span as long as the minimum span of 20 Hz is not violated.
Sweep points
As of firmware version 1.91, a minimum number of sweep points for each range can be
defined. The total number of available sweep points (defined by the global
setting) is then distributed between the ranges in consideration of the minimum
values. If necessary to fulfill all minimum sweep point requirements in all ranges, the
global
setting is increased. By default, each range is supplied with a
minimum of one sweep point.
This allows you to increase the resolution within a specific range for detailed analysis,
without increasing the overall number of sweep points and thus the measurement time
for the SEM measurement.
Symmetrical ranges
You can easily define a sweep list with symmetrical range settings, i.e. the ranges to
the left and right of the reference range are defined symmetrically. When symmetrical
setup is activated, the current sweep list configuration is changed to define a symmetri-
cal setup regarding the reference range. The number of ranges to the left of the refer-
ence range is reflected to the right, i.e. any missing ranges on the right are inserted,
while superfluous ranges are removed. The values in the ranges to the right of the ref-
erence range are adapted symmetrically to those in the left ranges.
Symmetrical ranges fulfill the conditions required for "Fast SEM" mode (see
ter 5.6.4.3, "Fast SEM Measurements"
Power classes
If the signal power level to be monitored may vary and the limits will vary accordingly,
you can define power classes, which can then be assigned to the frequency ranges.
Thus, the limits for the signal levels can be defined differently for varying input levels.
For instance, for higher input levels a transmission standard may allow for higher
Spectrum Emission Mask (SEM) Measurement
