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Configuring the Internal Baseband Source
R&S
®
SMBV100B
105
User Manual 1178.4460.02 ─ 03
3.4.1.5
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. This explains why coding schemes are not freely com-
binable with the modulation methods.
Refer to
Chapter 3.5.5.1, "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:
●
3.4.1.6
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
the output stream, especially while generating broadband signals. If the filter is too nar-
row, it cuts the signal. If the filter is too wide, the signal could be distorted by some
unwanted signals.
To fulfill wide range of requirements, the R&S
SMBV100B offers a wide selection of
predefined baseband filters. The predefined filters are designed for the special spec-
trum characteristics of the different communication standards. However, depending on
the selected filter form one or more filter parameters are provided for even more pre-
cise adjustment of the filter characteristic. You can select for example more steeper
edges or change the transition bandwidth. For more information on the provided set-
tings, refer to
"Impact of the Filter Parameters"
The selection of user-defined filter offers even more flexibility. The later is a useful
interface while filters with complex or proprietary form are required. For more informa-
tion, refer to
Predefined baseband filters
Refer to
Chapter 3.5.5.2, "Predefined Baseband Filters"
on page 142 for an overview
of the available baseband filters.
User filter
The user filter file must have extension
*.vaf
and can be created with the
Rohde
&
Schwarz software tool filter wizard.
The filter wizard (filtwiz) is a tool from Rohde
&
Schwarz designed for creating filter
files that can be imported on a R&S
SMBV100B. Its main purpose is the conversion of
user-defined finite impulse response (FIR) filters into the filter format (
*.vaf
). Beyond
this filtwiz provides designs for standard filters, e.g. root raised cosine (RRC), Gaus-
sian.
The program was developed on a 32-bit Microsoft Windows platform under MATLAB.
Common Functions and Settings in the Baseband Domain