The Spectrum Application (RF Measurements)
R&S
®
FPL1000
166
User Manual 1178.3370.02 ─ 11
Limit Lines in SEM Measurements
For the R&S
FPL1000, 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
Spectrum application application using the [Lines] function. For SEM measurements,
however, special limit lines are available via the "Sweep List" , and it is strongly recom-
mended 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 channel setups.
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:
Table 6-11: Limit check types
Limit check type
Pass/fail criteria
Limit line definition
"Absolute"
Absolute power levels must not
exceed limit line
Defined by the "Abs Limit Start"/ "Abs Limit
Stop" values for each range
"Relative"
Power deviations relative to the TX
channel power must not exceed limit
line
Defined by the "Rel Limit Start"/ "Rel Limit
Stop" values (relative to the TX channel
power), fixed for each range.
Measurements and Results
