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Configuring the internal baseband source
R&S
®
SMM100A
103
User Manual 1179.1341.02 ─ 05
(DVB). The QAM procedures 256QAM and 1024QAM are not specified in this stan-
dard, but have been produced according to the same basic principles.
For all FSK procedures you can set the symbol rate f
SYMB
up to a maximum value, see
data sheet. The frequency deviation (FSK deviation) of the MSK modulation is perma-
nently set to ¼ of the symbol rate. Also a variable FSK modulation with definable devi-
ation per symbol is available and for even greater flexibility. A user-defined modulation
mapping can be applied, see
User mapping
A user-defined modulation-mapping file can also be selected as modulation-mapping
source. Valid files have the extension
*.vam
and can be created with the
Rohde
&
Schwarz software tool-mapping wizard. The mapping wizard "mapwiz" is a
tool from Rohde
&
Schwarz designed for editing modulation schemes (for example
QPSK, 32QAM).
The main purpose of "mapwiz" is the assignment of logical symbol numbers to constel-
lation points and the selection of modulation-specific parameters. Also, the tool sup-
ports the creation of nearly any arbitrarily chosen constellation diagram. The output of
"mapwiz" is a mapping file (
*.vam
) that can be imported into a R&S
SMM100A. The
program was developed on a 32-bit Microsoft Windows platform under MATLAB.
For more information, see "Introduction to "mapwiz" Mapping Editor" at the
Rohde
&
Schwarz webpage.
The remote commands required to define the modulation settings are described in
Chapter 13.16.4.2, "SOURce:BB:DM subsystem"
Related settings:
●
Chapter 4.5.3.4, "Modulation settings"
4.4.1.5
Supported coding schemes
Coding is a technique used to improve the signal properties and signal reception and is
required only when using some types of modulation. In general, the coding schemes
are applied before modulation. The modulation symbols are coded directly before I and
Q values or frequency shifts are assigned. The applied coding is directly related to the
selected modulation methods. The relation implies that coding schemes are not freely
combinable with the modulation methods.
Refer to
Chapter 4.5.5.1, "Common coding algorithms"
on page 140 for overview on
the available coding combinations. This section also defines the modulation types for
which the various coding procedures can be used.
Related settings:
●
4.4.1.6
Supported baseband filters
In the wireless transmission technique, filters are applied to shape the baseband signal
before it is modulated on the RF. The selected baseband filter type and shape affect
Common functions and settings in the baseband domain