Nonlinear Testbed Design
Software Defined Radio (SDR) can move the complicated signal processing and handling procedures involved in communications from radio equipment into computer software. Consequently, SDR equipment could consist of only a few chips connected to an antenna. Due it’s relative simplicity, we focus on adopting SDRs to testbed setups.
Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC)
During the project evaluation-phase it turned out that small companies, e.g., start-ups, have problems with EMC tests. One of the largest obstacles are radiated emission measurements in a frequency range between 30MHz to 1GHz. In order to improve their quote in passing such a certification process, pre-compliance setups are investigated. The focus is put on low-cost equipment which is easily available and applicable to characterize typical battery-powered IoT devices.
On the receiver side, software-defined radios (SDRs) are analyzed regarding their capabilities for EMC measurements. The derived requirements are strongly influenced by CISPR 16-1-1 and are further examined by different radiation sources limited to a certain geometrical structure. Performance degrading aspects are reduced by simple modifications.
Because of its versatility, TEM cells have been identified as the appropriate measurement site. The size of such cells depends on the dimensions of the equipment-under-test (EUT). Furthermore, the field-uniformity decreases the larger the geometry gets. To analyze the respective cut-off frequency an HFSS simulation framework, triggered by Matlab, is constructed.
In conclusion, the main output of this work is to give an overview of SDRs differing in architecture, price, and performance for radiated pre-complinace measurements using TEM cells.
Measurement Filter Design
The Lattice Wave Digital Filter, which generates the required filter characteristic through a series of all-pass filters that can be designed in a way to minimize the group delay variation.
The Research Group Embedded Systems at the University Of Applied Sciences of Upper Austria was founded in 2005. The group’s working domain ranges from digital hardware design and embedded software engineering to digital signal processing as well as circuit, device and system simulation. Current focus is in Circuit and System Simulation, Near Fields Communication (NFC), high speed data links, and smart textiles. The research lab consists of 7 professors and 15 full and part time researchers. The projects are partly funded by the Austrian national research council FFG, the Austrian National Science Foundation FWF, from the European Community, and various industrial partners. The research activities in circuit and system simulation and design deal with algorithms and prototype software for radio frequency circuits. The focus here is on simulation engines for multi-rate circuits in the GHz range and mixed EM/device/circuit simulation for THz devices.
The Signal Processing Laboratory as part of the Research Group Embedded Systems focuses in the AMOR project on modeling of RF circuits and devices. A toolbox for automatic generation of SPICE compatible behavioral models based on the Hammerstein Wiener approach is under development.
Kai Bittner, Martin Steiger, and Hans Georg Brachtendorf, Harmonic Balance with Small Signal Perturbation, SCEE 2022, ACCEPTED
Martin Steiger, Kai Bittner, Hans Georg Brachtendorf, Non-linear RF Device Behavioral Models based on Hammerstein-Wiener Systems, MATHMOD 2022, ACCEPTED
Tomas Gotthans, Roman Marsalek, Linearity and Efficiency Enhancement Techniques for Satellite Communications, 2022 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications (PAWR), 2022, pp. 54-57, doi: 10.1109/PAWR53092.2022.9719692.
Moritz Tockner, Hans Georg Brachtendorf, Martin Steiger, Design of Wave Digital Filters with the TU Delft Toolbox, 2021 16th International Conference on Telecommunications (ConTEL), 2021, pp. 18-22, doi: 10.23919/ConTEL52528.2021.9495968.
Stefan Jahn, Hans-Georg Brachtendorf, DDS with Noise Reduction by Multiplier-Less Filter Methods, 2021 31st International Conference Radioelektronika (RADIOELEKTRONIKA), 2021, pp. 1-4, doi: 10.1109/RADIOELEKTRONIKA52220.2021.9420194.
Kristyna Pijackova, Tomas Gotthans, Radio Modulation Classification Using Deep Learning Architectures, 2021 31st International Conference Radioelektronika (RADIOELEKTRONIKA), doi: 10.1109/RADIOELEKTRONIKA52220.2021.9420195., 2021.
Lukas Jagla, Jan Kral, Tomas Gotthans, Acquisition System For Adaptation Of Digital Predistorter To Linearize Amplifiers Using Comparator, Proceedings II of the 26st Conference STUDENT EEICT 2020: Selected papers, ISBN 978-80-214-5868-0, 2020.