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Digital Predistorters with Low-Complexity Adaptation
Král, Jan ; Springer, Andreas (oponent) ; Roblin, Patrick (oponent) ; Götthans, Tomáš (vedoucí práce)
Modern communication systems often require digital predistorters (DPDs), advanced signal-processing units, to satisfy stringent demands on transmitter linearity and efficiency. Nevertheless, DPD significantly increases the hardware and computational complexity of transmitters, which leads to increased power consumption and expenses. Therefore, we propose methods to achieve lower hardware and computational complexity of DPD adaptation. The principle of real-valued feedback samples allows for saving one of two originally-needed feedback analogue-to-digital converters (ADCs), which implies reduced transmitter complexity and power consumption. Furthermore, the hardware and computational complexity can be reduced if the feedback samples for the DPD adaptation are undersampled and carefully selected. The proposed techniques select samples based on histograms and can reduce the required number of feedback samples to a few tens. The provided analyses show approximately 400-times reduced computational complexity achieved by the sample selection and 40-times reduced power consumption of the undersampling feedback ADCs. The real-valued feedback, its undersampling, and sample selection constitute fundamental principles of the proposed DPD adaptation with a level-crossing ADC, which is realised by a simple comparator. Replacing the conventional ADCs with a comparator significantly reduces the design complexity and power consumption. All the proposed and described techniques are accompanied by simulations, usually confirmed by measurements on real hardware, and compared with state-of-the-art methods. The final discussion analyses the limitations, usability and advantages of the proposed techniques. It shows that reducing complexity might not be universally applicable and all the design constraints and specifications must be carefully assessed.
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Rozhraní mezi LCD maticovým a grafickým displejem
Hartmann, Lukáš ; Svoboda, Roman (oponent) ; Götthans, Tomáš (vedoucí práce)
Tato práce se zabývá návrhem rozhraní mezi alfanumerickým displejem s řadičem HD44780 a grafickým displejem. Toto zařízení nahrazuje displeje s rozlišením 2x20, 4x20 a 4x40 znaků. Znaky k zobrazení lze posílat paralelním rozhraním jako u alfanumerických displejů, nebo pomocí rozhraní SPI. Pro nastavení jazykové sady slouží komunikační linka RS-485. Jazykové sady jsou uloženy v externí paměti flash.
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Senzorová síť WirelessHART
Řežucha, Tomáš ; Dřínovský, Jiří (oponent) ; Götthans, Tomáš (vedoucí práce)
Předložená diplomová práce je zaměřená na sestrojení demonstračního systému založeném na specifikaci WirelessHART a na popis průmyslového standardu WirelessHART, který je navržen pro použití v bezdrátových senzorových sítích. Z rozsáhlé specifikace WirelessHART jsou v práci nejprve popsané dvě nejnižší vrstvy síťového modelu: fyzická a linková; dále je popsaný burst mód a dynamické proměnné nezbytné pro publikováni dat v síti. Navržený a sestrojený demonstrační hardware je doplněn firmwarem a PC aplikacemi, které demonstrují možnosti systému v přehledném grafickém prostředí.
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Vehicle Location Detection and Distribution from Camera Images
Stryk, Filip ; Götthans, Jakub (oponent) ; Götthans, Tomáš (vedoucí práce)
This bachelor's thesis deals with vehicle location detection and tracking. Basic principles of deep learning and convolutional networks are presented. Deep learning based object detectors are described with a focus on YOLO and then compared in terms of accuracy and speed. A system for vehicle location detection and tracking using YOLOv4-tiny and SORT is designed, implemented and evaluated.
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Design of adaptive wireless video and data transmission
Lorenc, Tomáš ; Nykodým, Jiří (oponent) ; Götthans, Tomáš (vedoucí práce)
The aim of this thesis is to build a device that will be able to establish a wireless transmission of a real-time video stream and send the video to a computer where it will be displayed. The device is powered by the NVIDIA Jetson Nano and video is streamed wirelessly through a WiFi interface. In theoretical part described the problem of video transmission and video compression. The used codecs are h264, h265, and VP8. A subjective test to find the minimum acceptable value of video quality was performed. Measurements have been made to find the best codec for real-time video streaming. Measurements were also performed in real conditions. In conclusion, the results of the measurements and the selection of the best codec for real-time video streaming are commented.
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Optimizing neural network architecture for EEG processing using evolutionary algorithms
Pijáčková, Kristýna ; Maršálek, Roman (oponent) ; Götthans, Tomáš (vedoucí práce)
This thesis deals with an optimization of neural network hyperparameters for EEG signal processing using evolutionary algorithms. The incorporation of evolutionary optimization can reduce reliance on human intuition and empirical knowledge when designing neural network and can thus make the process design more effective. In this work, a genetic algorithm was proposed that is suitable for hyperparameters optimization as well as neural architecture search. These methods were compared to a benchmark model designed by an engineer with expertise in iEEG processing. Data used in this work are classified into four categories and come from St. Anne's University Hospital (SAUH) and Mayo Clinic (MAYO) and were recorded on drug-resistant epileptic patients undergoing pre-surgical examination. The results of the neural architecture search method were comparable with the benchmark model. The hyperparameter optimization improved the F1 score over the original, empirically designed, model from 0.9076 to 0.9673 for the SAUH data and 0.9222 to 0.9400 for the Mayo Clinic data. The increased scores were mainly due to the increased accuracy of the classification of pathological events and noise, which may have further positive implications in applications of this model in seizure and noise detectors.
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Digital Predistorters with Low-Complexity Adaptation
Král, Jan ; Springer, Andreas (oponent) ; Roblin, Patrick (oponent) ; Götthans, Tomáš (vedoucí práce)
Modern communication systems often require digital predistorters (DPDs), advanced signal-processing units, to satisfy stringent demands on transmitter linearity and efficiency. Nevertheless, DPD significantly increases the hardware and computational complexity of transmitters, which leads to increased power consumption and expenses. Therefore, we propose methods to achieve lower hardware and computational complexity of DPD adaptation. The principle of real-valued feedback samples allows for saving one of two originally-needed feedback analogue-to-digital converters (ADCs), which implies reduced transmitter complexity and power consumption. Furthermore, the hardware and computational complexity can be reduced if the feedback samples for the DPD adaptation are undersampled and carefully selected. The proposed techniques select samples based on histograms and can reduce the required number of feedback samples to a few tens. The provided analyses show approximately 400-times reduced computational complexity achieved by the sample selection and 40-times reduced power consumption of the undersampling feedback ADCs. The real-valued feedback, its undersampling, and sample selection constitute fundamental principles of the proposed DPD adaptation with a level-crossing ADC, which is realised by a simple comparator. Replacing the conventional ADCs with a comparator significantly reduces the design complexity and power consumption. All the proposed and described techniques are accompanied by simulations, usually confirmed by measurements on real hardware, and compared with state-of-the-art methods. The final discussion analyses the limitations, usability and advantages of the proposed techniques. It shows that reducing complexity might not be universally applicable and all the design constraints and specifications must be carefully assessed.
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Komunikační síť pro rojové létání bezpilotních letounů
Rajm, Jan ; Götthans, Tomáš (oponent) ; Janoušek, Jiří (vedoucí práce)
Tato bakalářská práce se zabývá vytvořením robustní komunikační sítě pro rojové létání bezpilotních letadel a jejím testováním. V první části práce jsou představeny požadavky na komunikační síť a jsou popsány vybrané komunikační standardy, které jsou schopné přenášet telemetrická data. Ve druhé části je popsán software potřebný pro přenos telemetrických dat a pro řízení bezpilotních letadel. Ve třetí části je představena navržená komunikační síť pro roj bezpilotních letadel. Jsou prezentovány její možnosti a odlišnost od sítí založených na jiných technologiích. V této části je také popsán postup jejího sestavení. Čtvrtá část práce se zabývá testováním a vyhodnocováním výsledků.
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Bluetooth lokalizace s nízkou spotřebou energie
Šlígl, Jan ; Nykodým, Jiří (oponent) ; Götthans, Tomáš (vedoucí práce)
Tato diplomová práce se zabývá návrhem lokalizačního zařízení v Bluetooth 5.2 s nízkou spotřebou. Lokalizace je provedena pomocí vytvořených zařízení tvořících beacony a navržené aplikace pro mobilní telefon. Dále také návrhem více druhů antén s různými směrovými charakteristikami, ziskem a velikostmi. Návrh bere v potaz především nízkou spotřebu energie, kompaktnost a nezávislost zařízení.
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