The Spectrum Application (RF Measurements)
R&S
®
FPL1000
160
User Manual 1178.3370.02 ─ 09
7.2.7.1
About the Measurement
The Spectrum Emission Mask (SEM) measurement defines a measurement that moni-
tors compliance with a spectral mask. The mask is defined with reference to the input
signal power. The R&S
FPL1000 allows for a flexible definition of all parameters in the
SEM measurement. The analyzer performs measurements in predefined frequency
ranges with settings that can be specified individually for each of these ranges.
In the basic Spectrum application, spectrum emissions can be measured for multiple
sub blocks of channels, where the sub blocks can include gaps or overlap, and define
separate masks. Radio signals using multiple standards can also be analyzed.
SEM measurement configurations can be saved to an XML file which can then be
exported to another application or loaded on the R&S
FPL1000 again later. Some pre-
defined XML files are provided that contain ranges and parameters according to the
selected standard.
To improve the performance of the R&S
FPL1000 for spectrum emission mask mea-
surements, a "Fast SEM" mode is available.
A special limit check for SEM measurements allows for monitoring compliance of the
spectrum.
7.2.7.2
Typical Applications
Spectrum Emission Mask measurements are typically performed to ensure that modu-
lated signals remain within the valid signal level ranges. These ranges are defined by a
particular transmission standard, both in the transmission channel and neighboring
channels. Any violations of the mask can interfere with other transmissions.
The 3GPP TS 34.122 standard, for example, defines a mask for emissions outside the
transmission channel. This mask is defined relative to the input signal power. Three
frequency ranges to each side of the transmission channel are defined.
7.2.7.3
SEM Results
As a result of the Spectrum Emission Mask measurement, the following results are dis-
played in a diagram (see also
"Limit Lines in SEM Measurements"
●
The measured signal levels
●
The result of the limit check (mask monitoring)
●
The defined limit lines
●
TX channel power "P"
●
The used power class
Multi-SEM measurements
Multi-SEM measurements are SEM measurements with more than one sub block. In
these measurements, each sub block has its own power class definitions. In this case,
the power class is not indicated in the graphical result displays.
Measurements and Results
