Measurements and Results
R&S
®
FSW
242
User Manual 1173.9411.02 ─ 43
limits for the signal levels can be defined differently for varying input levels. For
instance, for higher input levels a transmission standard can allow for higher power lev-
els in adjacent channels, whereas for lower input levels the allowed deviation can be
stricter. Up to four different power classes can be defined.
7.6.4.2
Limit Lines in SEM Measurements
For the R&S
FSW, the spectrum emission mask is defined using limit lines. Limit lines
allow you to check the measured data (that is, the trace results) against specified limit
values. Generally, it is possible to define limit lines for any measurement in the Spec-
trum application application using the [Lines] function. For SEM measurements, how-
ever, special limit lines are available via the "Sweep List", and it is strongly recommen-
ded that you use only these limit line definitions.
In the "Sweep List", you can define a limit line for each power class that varies its level
according to the specified frequency ranges. Special limit lines are automatically
defined for each power class according to the current "Sweep List" settings every time
the settings change. These limit lines are labeled "_SEM_LINE_<xxx>_ABS<0...3>"
and "_SEM_LINE_<xxx>_REL<0...3>", where <xxx> is an index to distinguish limit
lines between different channels.
The limit line defined for the currently used power class is indicated by a red line in the
display. The result of the limit check is indicated at the top of the diagram. Note that
only "Pass" or "Fail" is indicated; a "Margin" function as for general limit lines is not
available.
The indicated limit line depends on the settings in the "Sweep List". Several types of
limit checks are possible:
Spectrum Emission Mask (SEM) Measurement
