R&S FSW Series, Руководство пользователя

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Measurements and Results
R&S
®
FSW
236 User Manual 1173.9411.02 ─ 43
● How to Perform a Spectrum Emission Mask Measurement ..................................267
● Measurement Example: Multi-SEM Measurement ................................................272
● Reference: SEM File Descriptions ........................................................................ 273
7.6.1 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
FSW 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
FSW again later. Some prede-
fined XML files are provided that contain ranges and parameters according to the
selected standard.
To improve the performance of the R&S FSW for spectrum emission mask measure-
ments, a "Fast SEM" mode is available.
A special limit check for SEM measurements allows for monitoring compliance of the
spectrum.
7.6.2 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.
7.6.3 SEM Results
As a result of the Spectrum Emission Mask measurement, the following results are dis-
played in a diagram (see also
Chapter 7.6.4.2, "Limit Lines in SEM Measurements" ,
on page 242):
●
The measured signal levels
●
The result of the limit check (mask monitoring)
●
The defined limit lines
●
TX channel power "P"
●
The used power class
Spectrum Emission Mask (SEM) Measurement