Configuring the Internal Baseband Source
R&S
®
SMW200A
247User Manual 1175.6632.02 ─ 30
Related settings:
●
"Coding" on page 265
5.5.1.6 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 SMW offers a wide selection of prede-
fined baseband filters. The predefined filters are designed for the special spectrum
characteristics of the different communication standards. However, depending on the
selected filter form one or more filter parameters are provided for even more precise
adjustment of the filter characteristic. You can select, for example, more steeper edges
or change the transition bandwidth. For more information on the provided settings, see
"Impact of the Filter Parameters" on page 248.
The selection of user-defined filters offers even more flexibility. Use these filters if you
need filtering with filters of complex or proprietary form are required. For more informa-
tion, refer to "User filter" on page 247.
Predefined baseband filters
See Chapter 5.6.5.2, "Predefined Baseband Filters", on page 293 for an overview of
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 SMW. 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), Gaussian.
The program was developed on a 32-bit Microsoft Windows platform under MATLAB.
For more information, see "Introduction to "filtwiz" Filter Editor" at the
Rohde & Schwarz webpage.
The remote commands required to define the filter settings are described in Chap-
ter 14.19.4.2, "SOURce:BB:DM Subsystem", on page 988 and the corresponding sec-
tion in the user manual of each firmware option.
Related settings:
●
Chapter 5.6.3.5, "Filter Settings", on page 274
●
Filter settings in the dialogs of the firmware options
Common Functions and Settings in the Baseband Domain
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