Magnetic Levitation Device

This paper brings some general knowledge about magnetic levitation devices used for aesthetic and entertainment purposes. Two major principles are discussed while their advantages and disadvantages are pointed out. A new principal of hanging-type levitation device is constructed where permanent magnets are implemented into closed-loop magnetic system for lower power consumption. The function of control system is described and power consumption measurements are done

Persistent homology approach for human presence detection from 60 GHz OTFS transmissions

Orthogonal Time Frequency Space (OTFS) is a new, promising modulation waveform candidate for the next generation integrated sensing and communication (ISAC) systems, providing the environment-awareness capabilities together with high speed wireless data communications. This paper presents original results of OTFS-based person monitoring measurements in the 60 GHz millimeter-wave frequency band under realistic conditions, without the assumption of an integer ratio between the actual delays and Doppler shifts of the reflected components and the corresponding resolution of the OTFS grid. As the main contribution of the paper, we propose the use of the persistent homology technique as a method for processing of gathered delay-Doppler responses. We highlight the advantages of persistence homology approach over the standard constant false alarm rate target detector for selected scenarios

Utilization of circuit elements described by fractional-order dynamics in analog phase shifters

Práce se zabývá matematickým popisem, metodami návrhu a využitím fraktálních pasivních RC struktur - dvojpólů - v určité kmitočtové oblasti. Jsou zde uvedeny dvě metody pro návrh těchto struktur a jedna z nich je využita pro návrh a konstrukci tří fraktálních dvojpólů. Ty jsou podrobně změřeny a zhodnoceny. Jsou zde teoreticky rozebrány analogové posouvače fáze využívající tento fraktální prvek a následně jsou prakticky realizovány a změřeny. Závěrem se práce stručně věnuje metodě návrhu fraktálních dvojbranů pomocí obecných bikvadraturních filtrů.This document deals with fractional passive dipole structures, their mathematical description, design methods and practical use with respect to limited frequency range. Two fractional dipole design methods are being described while one of them is used for practical realization of three fractional dipole samples. All of them are well measured and documented. Analog phase shifters implementing this fractional-order dipole are being discussed theoretically and they are practically constructed and measured. Concisely the fractional-order two-port design method implementing biquadratic filters is described.

Magnetic Levitation Device

This paper brings some general knowledge about magnetic levitation devices used for aesthetic and entertainment purposes. Two major principles are discussed while their advantages and disadvantages are pointed out. A new principal of hanging-type levitation device is constructed where permanent magnets are implemented into closed-loop magnetic system for lower power consumption. The function of control system is described and power consumption measurements are done

X-Band Earth Observation Satellite Software Defined Radio

This article presents the digital baseband receiver for signals from the EOS-PM-1 X-band Earth observing satellite. The conventional SDR is used to provide samples of the baseband signal. The MATLAB software is used for simulating the O-QPSK satellite signal in baseband, algorithms for the Doppler frequency shift and additional frequency offset removal, carrier phase synchronization, symbol timing synchronization and the phase ambiguity removal

X-band Earth Observation Satellite Software Defined Receiver

Práce se zabývá procesem návrhu digitálního přijímače pro signály družic dálkového průzkumu Země v pásmu X. V první části je uveden seznam družic které umožnují příjem vědeckých dat pomocí amatérských neautorizovaných stanic. Jsou zde vypsány základní signálové parametry některých družic, z nichž EOS-PM-1 je zvolena jako hlavní objekt pro návrh přijímače. Ve druhé části je použit software MATLAB pro simulaci družicového O-QPSK signálu v základním pásmu, mechanizmu kompenzace kmitočtového ofsetu, synchronizaci nosné, symbolové synchronizaci, rámcové synchronizaci a odstranění fázové dvojznačnosti vlivem modulace. Třetí část práce pojednává detailněji o implementaci jednotlivých bloků přijímače do FPGA při použití aritmetky s pevnou řádovou čárkou. Je zde popsána metoda pro verifikaci celého designu v reálném čase a závěrem je zde uvedeno porovnání výsledků měření touto metodou a výsledků simulace.This thesis describes the process of designing the digital baseband receiver for the O-QPSK modulated signals from the X-band Earth observing satellites. The satellites provide free direct data broadcast for the civilian ground stations. The first part lists the main downlink parameters of several EOS satellites, choosing EOS-PM-1 as the main target. The second part uses MATLAB software to simulate the O-QPSK satellite signal in baseband, offset frequency compensation, carrier phase synchronization, symbol timing synchronization, frame synchronization and the carrier phase ambiguity removal. The third part elaborates previously simulated design blocks with respect to the FPGA implementation using fixed-point arithmetic. A sophisticated method of verifying the whole design in real time is introduced and performance comparison between simulations and measurements is done.

Analog Phase Shifters of Fractional Order

This paper brings some general knowledge about linear analog fractional-order phase shifters. These useful building blocks can perform continuous phase shift with adjustable userdefined asymptotic values. Design process starts with predefined transfer function in which at least single fractional-order passive two-terminal device is needed. These elements are made as approximations in limited frequency range by using fully passive ladder structures where only resistors and capacitors are employed