Rohde & Schwarz SMM100A, Руководство пользователя

Страница: 148 / 1088

Configuring the internal baseband source
R&S
®
SMM100A
148 User Manual 1179.1341.02 ─ 05
4.6.2 About ARB
This section provides background information on the ARB functionality and the impact
of the provided settings.
For a description of the multi-carrier, multi-segment and multi-carrier continuous wave
functions, refer to:
●
Chapter 4.10, "Generating multi-carrier signals" , on page 230
●
Chapter 4.9, "Generating multi-segment waveform files" , on page 200
●
Chapter 4.11, "Generating multi-carrier continuous wave signal" , on page 247
4.6.2.1 Waveform files sources
In ARB mode, the R&S SMM100A uses ARB waveform files to obtain the digital I/Q
data of the baseband signal. The R&S SMM100A can play back any waveform file
saved on a network drive but it can also generate and play back simple waveforms for
test purposes.
What is a waveform?
A waveform is a file with specified file format containing raw IQ samples. The IQ values
are calculated in advance and saved in waveform files with a predefined extension
*.wv
.
When waveforms are created by the R&S SMM100A, the instrument inserts a wave-
form header at the beginning of each created ARB file. The header of the generated
I/Q data files consists of "tags" which are enclosed in braces { }.
For detailed description on all available tags and for information on how to query them
or to create waveforms manually, refer to
Chapter 4.6.5, "Tags for waveforms, data and
control lists" , on page 177.
Waveform file sources
Depending on whether the R&S SMM100A creates the waveform files itself or not, the
following waveform file sources can be distinguished:
●
Internally generated waveforms
The ARB generator enables the calculation and the generation of multi-segment
and multi-carrier waveform files. The ARB generator provides also a built-in func-
tion to create a test waveform (e.g. a sine or rectangle signal) and keep it as a file
or in the RAM.
Several digital standards provide the special function "Generate Waveform File".
With this function, the calculated signals are saved as a waveform file that you can
play back using the ARB generator.
●
Externally generated or created waveforms
The ARB generator processes externally created waveform files, for example:
–
The waveform files generated by the software R&S WinIQSIM2, the
R&S ARB Toolbox, the R&S Pulse Sequencer
– Signals calculated using a mathematical program such as MATLAB.
See Chapter 4.6.5, "Tags for waveforms, data and control lists" , on page 177.
Using the arbitrary waveform generator (ARB)