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SMV-2022-61: Development of advanced programmable acquisition system with pulse generator
Vondra, Vlastimil
Assessment of the equipment specification in terms of the equipment implementation possibilities using the contractor's instrumentation. Analysis of the requirements of the assignment and development of the generator solution methodology. Preparation of a proposal for implementation according to the desired characteristics. Manufacturing mechanical and electrical parts and purchasing the necessary components. Verification of theoretical initial requirements by practical measurements at a designated location. Assembling 1 piece of experimental equipment. Installation, calibration of equipment at the filling site. Operator training at the client's.
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Automatic determination of the pulse wave velocity in a body segment
Kampo, Dávid ; Svačinová, Jana (referee) ; Vondra, Vlastimil (advisor)
This Bachelor´s thesis deals with a propagation of a pulse wave velocity in different body segments and its measurement through bioimpedance. In connection with this topic, the work includes a profound description of a pulse wave and its velocity in regards to diagnostics and prevention of cardiovascular diseases that have been prevailing in recent years. During the process of determination of PWV, ECG is recorded, as it helps to accurately estimate the relevant transition times and the reulting PWV. The main purpose of this work is to validate that PWV can be determined without supportive ECG signals, what as a result makes the whole process simpler, more effective and available. The main target of this work has been successfully achieved and the algorithm for an evaluation of transition times and determination of PWV is described in the work. Moreover, the algorithm is implied to the structure of GUI in Matlab programm where the interface has been designed to suit the user´s needs to analyse PWV. Highlighting the validation process and functionality of the algorithm, signals from 21 subjects have been used to assess some of the most frequent analysed PWVs and all average values of velocities are within a physiological range from 5 m/s to 15 m/s. cfPWV is considered as a golden standard when it comes to PWV and the average value for all 21 subjects has been estimated to 7,54 m/s what corresponds with values from scientific studies that have been assessing cfPWV.
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Evaluation of pulse Wave Velocity Based on Whole-Body Bioimpedance
Soukup, Ladislav ; Tyšler, Milan (referee) ; Vrba, Jan (referee) ; Vondra, Vlastimil (advisor)
This thesis deals with the methodology of use of whole-body impedance cardiography for evaluation of pulse wave velocity. The first three chapters explain selected hemodynamic properties of the arterial system related to the issue of pulse wave propagation. At the same time the ordinary methods for estimation, its disadvantages and merits has been summarized. Points at issue of whole-body impedance evaluation methodology for pulse wave velocity are researched in second part of this thesis. In order that analysis the procedure for correct methodology has been determined. Particularly determination of reference proximal point for calculation of transit time towards aortic valve, and design and accuracy of transit distance measurement were discussed. Based on the obtained data, a calculation of representative pulse wave velocity to eight limb locations was performed.
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Frequency synthesizer for microwave communication systems
Klapil, Filip ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
The main aim of the thesis is to develop a solution of a frequency synthesizer for a microwave communication systems. Specifically, it suggests a design for frequency synthesizer with phase-locked loop. At beginning of the thesis the principle and basic properties of this method of signal generation are explained. Then it is followed by a brief discussion of the parameters of synthesizers and their influence on design. Another part of the work is the analysis of circuit the frequency synthesizer with the phase-locked loop MAX2871, which is followed by a proposal for the design of the frequency synthesizer module hardware. The last part of the work deals with practical implementation, verification of function and measurement of achieved parameters and their evaluation.
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SMV-2019-58: Development of programmable acquisition system with pulse generator
Vondra, Vlastimil
The contract research project consists of:\n• assessment of the equipment specification in terms of the equipment implementation possibilities using the contractor's instrumentation,\n• analysis of the requirements of the assignment and development of the generator solution methodology,\n• preparation of a proposal for implementation according to the desired characteristics,\n• manufacturing mechanical and electrical parts and purchasing the necessary components,\n• Verification of theoretical initial requirements by practical measurements at a designated location\n• assembling 1 piece of experimental equipment,\n• installation, calibration of equipment at the filling site,\n• Operator training at the client's.\n
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Low Noise Amplifier for the S Band
Benites Ayala, Ivan Alejandro ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
This master's thesis presents the design and the realization of a low noise amplifier (LNA) for the S band of radio frequency spectrum from 2.3 GHz to 2.4 GHz. This thesis is mainly focused on stability and impedance matching networks study. Ansoft Designer and ANSYS HFSS programs are used for this design to simulate the LNA. Different low noise devices are simulated in order to find the best results for the final design. Moreover, a coaxial cavity resonator is designed in the input of the LNA and works as a band pass filter. Finally, the LNA is fabricated and its properties compared with the simulation results.
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Hemodynamic modelling in the calf — A pilot study
Matějková, M. ; Jurák, Pavel ; Soukup, L. ; Halámek, Josef ; Viščor, Ivo ; Langer, P. ; Vondra, Vlastimil
With increasing age, the cardiovascular system loses its efficiency. The goal of this work was to investigate the hemodynamic system response to a head-up tilt test in two groups of different aged people. We used a model for describing this response in the right calf based on a non-invasive, non-occlusive, bioimpedance signal measurement technique. A decrease in the bioimpedance value in the calf during the head-up tilt test is associated with the accumulation of blood in the calf, which can be expressed by a model parameter. Subjects were examined in both a head-up tilt test and a supine position. 50 healthy non-smoking volunteers were divided into two groups according to age. The impedance signal during the tilt test for each subject was fitted by a model exponential function: Z0 model EF(t) =A exp(-t/B)+C, where Z0 model EF(t) is the calculated model of electrical impedance in the calf by an exponential function, A is the amplitude of impedance change, B is the time constant of the impedance decrease, C is the value of the steady state after the tilt test and t denotes time. A lower time constant B shows a faster filling of the vascular system in the investigated part. The Mann-Whitney test (p-value<;0.005) revealed that the time constant B for the older group was significantly lower than for the young group (145.24+/- 80.28 vs. 239.23+/-136.59 sec.). A lower time constant value means a faster response to blood filling in the lower limbs and directly reflects decreased vessel elasticity. This time constant was lower in the older group. The results show increased vessel stiffness in old age and could lead to a non-invasive evaluating the cardiovascular system state.
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SMV-2017-29: Current generator for 3D space coil systém GMP4
Vondra, Vlastimil
Development of an advanced experimental system for adjustment of the magnetic field inside the 3D coil system according to defined requirements, including the time programming of the magnitude and direction of the magnetic. field vector. The system is equipped with accurate monitoring of the actual magnitude of mg. field vector that is connected in the feedback loop.
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Solid State Power Amplifier for the L-Band
Pecen, Vojtěch ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
The goal of this diploma's thesis is to create a design of a two stages amplifier working in a band reserved for the secondary surveillance radar at the frequency of 1090 MHz. Output power of the amplifier should be 20 W and efficiency should be as high as possible. Because of this the second stage is designed in class C. Contents of this diploma's thesis include a theoretical analysis, simulations of the amplifier parameters, comparison of the Ansys Designer and AWR Microwave Office simulation programs and design of both stages of the amplifier, followed by a comparison of the measured parameters with the simulations.
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