Configuring the Internal Baseband Source
R&S
®
SMW200A
264User Manual 1175.6632.02 ─ 16
4.6 Generating Custom Digital Modulated Signals
The R&S SMW can generate digital modulation signals with user-definable characteris-
tics. The baseband filtering and the symbol rate can be set within wide limits.
4.6.1 Required Options
The equipment layout for generating the digital modulation signals includes
●
Option standard or wideband baseband generator (R&S SMW-B10/-B9) per signal
path and
●
Option baseband main module, one/two I/Q paths to RF (R&S SMW-B13/-B13T) or
Option wideband baseband main module two I/Q paths to RF (R&S SMW-B13XT)
4.6.2 About the Custom Digital Modulation
An introduction to the supported filter, modulation, and coding schemes are provided
in:
●
Chapter 4.5.1.6, "Supported Baseband Filters", on page 248
●
Chapter 4.5.1.4, "Supported Modulation Types", on page 247
●
Chapter 4.5.1.5, "Supported Coding Schemes", on page 248.
Interdependency between selected modulation type and coding scheme and
handling of conflicting settings
The applied coding is directly related to the selected modulation methods. The availa-
ble coding schemes listed in Chapter 4.6.5.2, "Common Coding Algorithms",
on page 295 are not freely combinable with modulation methods.
Obviously, having selected a modulation procedure, not every combination of the fur-
ther modulation parameters "Symbol Rate" and "Coding" is possible. These restrictions
inevitably result in conflicting settings if you chang a parameter and leads to a prohibi-
ted combination.
An inappropriately change of a parameter triggers a settings conflict. A conflicting set-
ting is indicated by a message on the "Info" line in the display. Although the R&S SMW
displays the selected settings, the generated modulation signal does not correspond to
this display. The displayed message disappears when a conflict-free setting is
selected.
Refer to Chapter 15, "Troubleshooting and Error Messages", on page 1172 for a list of
the possible settings conflicts and messages in digital modulation.
Generating Custom Digital Modulated Signals
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