Configuring the Internal Baseband Source
R&S
®
SMW200A
301User Manual 1175.6632.02 ─ 16
4.7.2 About the 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 4.9, "Generating Multi-Carrier Signals", on page 354
●
Chapter 4.8, "Generating Multi-Segment Waveform Files", on page 324
●
Chapter 4.10, "Generating Multi-Carrier Continuous Wave Signal", on page 372
4.7.2.1 Waveform Files Sources
In ARB mode, the R&S SMW uses ARB waveform files to obtain the digital I/Q data of
the baseband signal. The R&S SMW can replay any waveform file stored on a network
drive but it can also generate and replay simple waveforms for test purposes.
A waveform is a file with specified file format containing raw IQ samples. The IQ values
are calculated in advance and stored as waveform files with a predefined extension
*.wv. When created by the R&S SMW, the instrument inserts a tagged waveform
header at the beginning of each created ARB file. For more information, refer to Chap-
ter 13.18.4.4, "Waveform, Data and List Format", on page 961.
Depending on whether the R&S SMW creates the waveform files itself or not, two
waveform files 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 stored as a waveform file that can be
afterwards played by the ARB generator.
●
Externally generated waveforms
The ARB can also process externally generated waveform files. For example, the
waveform files generated on a PC by the Windows software package R&S WinIQ-
SIM2, the software R&S ARB Toolbox, the R&S Pulse Sequencer software or sig-
nals calculated using a mathematical program such as MATLAB.
The externally generated waveform files can be loaded into the instrument via one
of the available interfaces (USB, LAN or GPIB). Usually, the waveform file is stored
on one of the network drives which are accessible for the operating system.
4.7.2.2 ARB Test Signals
The following test signals are available:
●
Sine Test Signal: Two sinewave signals with a selectable (but equal) number of
samples per period and equal frequencies. When the generation is triggered, the
number of samples per period, together with the frequency of the test signal, deter-
Using the Arbitrary Waveform Generator (ARB)
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