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Beamforming using microphone arrays
Bartoň, Zdeněk ; Schimmel, Jiří (referee) ; Míča, Ivan (advisor)
The aim of the master thesis is to sum up theoretical information about beamforming methods of microphone arrays and to verify their functionality. At the beginning of this work there are simulated different varietes of linear uniform and nonuniform microphone arrays and circular arrays. The results are verificated by a practical measurement in ideal conditions. Then I will focuse on implementation of the DAS(Delay And Sum), SAB(Sub Array Beamforming), CDB(Constant Directivity Beamforming), CDB-CA(CDB-Circular Arrays) beamformer including theoretical and practical verification of the functionality in ideal conditions. At the end of this thesis are all beamforming methods compared with each other at SNR(signal to Noise Ratio) and directivity parameters.
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Unidirectional plasmonic antennas
Formanová, Veronika ; Hrtoň, Martin (referee) ; Kvapil, Michal (advisor)
This thesis deals with directional V-shaped plasmonic antennas. In the thesis, an analytical model of antenna emission is proposed. The results of analytical computations are compared with results of numerical simulations in Lumerical FDTD Solutions package. Also, the process of fabrication of such antennas by electron beam lithography and measurement of optical properties using Fourier infrared spectroscopy is described and measured antenna resonant spectra are shown. Finally, there is a proposal of an experiment to prove the emission directivity of fabricated V-shaped antennas.
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Sound emission directivity model
Zdvyhal, Marian ; Hájek, Roman (referee) ; Hejčík, Jiří (advisor)
This diploma thesis solves creation of a computing model of sound propagation for determination of acoustic pressure level around multiple point sound source with consideration of sound directivity of each source (compresor and fan). Thesis contains neccesary theoretical knowledge for creation of computing model and basics of sound measuring, theoretical computing model, measurement data of real unit and model configuration for real measured values. Computing code of the model in Visual Basic for MS Excel is a part of the thesis.
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Design and realisation of microwave directional coupler
Nejedlý, Miroslav ; Motl, Milan (referee) ; Dvořák, Radek (advisor)
The diploma thesis deals with microwave directional coupler. The paper presents some of the microwave directional coupler and an analysis of bifurcations. The paper also discussed the various techniques of bifurcations and the bandwidth to which they are making. Proposal is implemented in two selected directional couplers and determining their size. They also performed using the selected simulation program selected two bifurcations. Furthermore, these couplers are made on the perimeter of the analyzer is verified by their actions and are verified by the actual parameters of the coupler.
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Model of the metropolitan optical network
Prudík, Jiří ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
The purpose of this master’s thesis is foremost to provide a simple guide how to build elements of optical metropolitan area network. The basic model consists to sequence of construction, network topology, passive and active parts. The collection contains examples of alternative technology such as Wireless LAN with different frequency. The optical network construction based on optical cable, fibres, splices, trays, adapters, connectors and active parts for example a lot of media convertor models. After that there are demonstrating type of wavelength division multiplexer used in metropolitan area network – passive planar PCL splitter. One of the passive planar splitter are used to increase optical fibre channel. At the end of the collection a simplified examples of used measurements – optical time domain reflectometry and optical fibre transmission. Contains standard protocols or reflectogram. The conclusion of this thesis summarizes costs of FTTb (Fibre To The Building) model of optical metropolitan area network in Czech republic and future contribution for society.
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Analysis of the radiation of accordions and designing the spatial arrangement of microphones for their recording
Rapáč, Marek ; Musil, Jaroslav (referee) ; Jirásek, Ondřej (advisor)
This bachelor’s thesis deals with the analysis of the spectrum and directivity of three different accordions.Two of the analyzed instruments are piano accordions with standard basses, one accordion is a special type of piano accordion, the so-called bass accordion.The effect of the played tone and used register on the spectrum and on the directionality of the resulting tone is described. The resulting findings are also compared between different accordions. The final part of the thesis is devoted to the practical use of stereo microphone techniques for high-quality, faithful and listener-friendly recording of the accordion sound. In conclusion, these findings are evaluated and the most suitable stereo microphone technique for recording the accordion is presented here.
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The influence of the diameter and depth of the hole in the whistle on the timbre and directionality
Borovičková, Barbora ; Mojdl, Edgar (referee) ; Jirásek, Ondřej (advisor)
This bachelor’s thesis examines the influence of the diameter and depth of the holes in the recorder on the timbre and directionality of the resulting tone. For measurements and subsequent data analysis, nine flute body prototypes were made from three different materials and with three different wall thicknesses. During the measurement, holes with different diameters were drilled into the prototypes. Thanks to this procedure, it was possible to separate desirable influences from undesirable ones. The measured data were analyzed in the Matlab environment.
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Numerical simulation of of human voice propagation through the vocal tract and in the space around the body
Batelka, Jiří ; Hájek, Petr (referee) ; Švancara, Pavel (advisor)
This master's thesis handles description of the source-filter theory of voice production, anatomy of larynx, possible approaches to voice production modelling and selected works using these approaches in first chapter. Brief description of selected quantities used in acoustics and model creation follows. Models of only the head and head with female and male torso are created, including mesh testing to determine suitable element size. Models created in this thesis focus on description of voice propagation primarily in front of body and on influence of torso on sound propagation. Inclusion of torso results in fluctuations in frequency domain in range from 1 000 Hz to 8 000 Hz, more pronounced near lower frquencies. In transverse plane the presence of torso manifests in lower SPL in front of mouth and higher SPL on the sides for several frequencies. Regions with decrease of SPL in front of mouth are coindicent with frequencies, where higher SPL on sides in comparision with direction in front of the mouth is evident. These observations are in agreement with other works. No significant differences were observed between models with different torsos in the transverse plane. Below the transverse plane differences between models with different torsos can be observed, for example for some frequencies decrease in SPL isn't observed in front of mouth in directivity diagrams for model with male torso.
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