Configuring the internal baseband source
R&S
®
SMM100A
104
User Manual 1179.1341.02 ─ 05
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
SMM100A offers a wide selection of pre-
defined 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, steeper edges or
change the transition bandwidth. For more information on the provided settings, see
"Impact of the filter parameters"
The selection of user-defined filters offers even more flexibility. Use these filters if you
need to filter with filters of complex or proprietary form are required. For more informa-
tion, refer to
Predefined baseband filters
See
Chapter 4.5.5.2, "Predefined baseband filters"
on page 142 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
SMM100A. 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.
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
ter 13.16.4.2, "SOURce:BB:DM subsystem"
on page 770 and the corresponding sec-
tion in the user manual of each firmware option.
Related settings:
●
Chapter 4.5.3.5, "Filter settings"
●
Filter settings in the dialogs of the firmware options
Impact of the filter parameters
The following is a simple description of the filter parameters and the way they affect the
main filter characteristics. Changing filter parameters is an effective way to ensure that
the entire bandwidth of the desired signal is allowed to pass and adjust the filter form to
reach the spectrum mask requirements.
Common functions and settings in the baseband domain
