R&S WinIQSIM2 Software Manual - Rohde & Schwarz

R&S ® WinIQSIM2
Graphical User Interface
Baseband Block
5.10 Baseband Block
The Signal Generation Software R&S WinIQSIM2 provides you with the ability to generate
digital modulation signals in accordance with the definitions in the digital standards
or with user-definable characteristics. You can then load these files into the R&S Signal
Generator in the form of waveform files.
Several digital standards are provided, plus digital modulation with user-definable signal
characteristics and generation of multi carrier CW signals with the aid of Multi Carrier
CW.
The settings for digital modulation can be accessed in the block diagram via the Baseband
function block.
The equipment layout for generating the internal, digital modulation signals includes the
options Multi Carrier CW Signal Generation and the option Import IQ Data.
In addition, the appropriate option is required for the digital standards. These options are
specified in the description of the respective standard.
In the subsequent signal route the baseband signals can be loaded with noise (see ​
chapter 5.9.2, "Working with the AWGN Block", on page 43).
5.10.1 Data and Signal Sources in Baseband
This section describes the common characteristics of the signals used for generating the
baseband signal for all standards, including for example all listed data sources. The
selection in the digital menus at any given time depends on the parameter and standard
concerned and is clear from the selection list offered in the dialog. The external data
sources may therefore not be available in certain cases.
Characteristics which are uniquely specific to particular standards are described in the
corresponding manual.
The following input signals are used when digital modulation signals are being generated:
●
●
Modulation data
Control signals
Externally computed waveform files can be loaded in the instrument using computer
interfaces or IEC bus.
Internally the "Multi Carrier CW" menu for defining multi carrier waveforms is available
(see ​chapter 5.10.3, "Multi Carrier Continuous Wave", on page 84).
5.10.1.1 Internal PRBS Data and Data Patterns
PRBS generators deliver pseudo-random binary sequences of differing length and duration.
They are known as maximum length sequences, and are generated with the aid of
ring shift registers with feedback points determined by the polynomial.
By way of example, the diagram below shows a 9-bit generator with feedback to registers
4 and 0 (output).
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