National Repository of Grey Literature 6 records found  Search took 0.01 seconds. 
Simulation of Sound Field of Multiple Sound Sources
Kohoutek, Jan ; Kurc, David (referee) ; Schimmel, Jiří (advisor)
The main task of this bachelor thesis is description of interaction of sound waves in field. To understand the whole topic important physical laws related to sound waves propagation are defined. It also deals with frequency and directional response of ideal point source which compares with real measured responses of direct-radiating electrodynamic loudpeaker. Thesis are shown some examples of sound fields on which are specified their behavior. It also desribe main properties for right functionality of line-array source. In practical part are measured acoustic pressure values which lead to creating a interpolation map of sound pressure level. This obtained map was compared with theoretical acoustic field. Part of this bachelor thesis is program which enable to simulate acoustic field created under variable sound and environment properties.
Ultrasonic Anemometer
Křepelka, Pavel ; Fialka, Jiří (referee) ; Beneš, Petr (advisor)
In the first section of this document, there are described principles of the wind measuring. Anemometers can be divides by physical principles to mechanical (propeller or cup), ultrasonic anemometers and thermoanemometers. This paper is focused to ultrasonic anemometers. In the next part, there are described principles of sound propagation in the atmosphere. There are studies of measurement theory and comparing of different approaches. Completed solutions are presented in patent exploration. Afterwards, there are introduction of market research. Important parameters of ultrasonic anemometers are highlighted. Main aim of work is designing prototype of ultrasonic anemometer. Software, hardware and construct of experimental anemometer were designed. Created anemometer was calibrated in aerodynamics tunnel and results were compared with simulation output.
Automation of measurement of directional characteristics of sound sources
Nimmerrichter, Benjamin ; Liska, Matej (referee) ; Schimmel, Jiří (advisor)
This bachelors thesis deals with the topic of automating the measuring of directional sound radiation characteristics of sound sources with the use of one to sixteen, possibly thirty-two microphones connected to an audio device, which supports the ASIO driver technology, which is connected to a computer with an installation of the MATLAB software. In the scope of this thesis a program was created, which is capable of measuring the 2D and 3D directional characteristics of sound sources and it can show the frequency spectrum of the signal. This work addresses the problematics of the effective value of discrete signals, calibration of microphones for measuring sound pressure level, the calculation and measuring of the level of acoustic pressure in dB (SPL), the autocorrelation of a discrete signal, plotting of the measurement in a polar or spherical plot and the calculation of the signal to noise ratio. This thesis contains a theoretical introduction to the measurement and to the propagation of sound, then the composition of the program and the measurement and an assessment of the measured results.
Estimation of acoustic wave propagation velocity in a steel sample to monitor creep changes using acoustic emission
Tichavský, Petr ; Slunéčko, T. ; Svobodová, M. ; Chmela, T.
The report describes the measurement of the sound propagation velocity in a sample of material subjected to heat and mechanical stress by means of an acoustic emission.
Simulation of Sound Field of Multiple Sound Sources
Kohoutek, Jan ; Kurc, David (referee) ; Schimmel, Jiří (advisor)
The main task of this bachelor thesis is description of interaction of sound waves in field. To understand the whole topic important physical laws related to sound waves propagation are defined. It also deals with frequency and directional response of ideal point source which compares with real measured responses of direct-radiating electrodynamic loudpeaker. Thesis are shown some examples of sound fields on which are specified their behavior. It also desribe main properties for right functionality of line-array source. In practical part are measured acoustic pressure values which lead to creating a interpolation map of sound pressure level. This obtained map was compared with theoretical acoustic field. Part of this bachelor thesis is program which enable to simulate acoustic field created under variable sound and environment properties.
Ultrasonic Anemometer
Křepelka, Pavel ; Fialka, Jiří (referee) ; Beneš, Petr (advisor)
In the first section of this document, there are described principles of the wind measuring. Anemometers can be divides by physical principles to mechanical (propeller or cup), ultrasonic anemometers and thermoanemometers. This paper is focused to ultrasonic anemometers. In the next part, there are described principles of sound propagation in the atmosphere. There are studies of measurement theory and comparing of different approaches. Completed solutions are presented in patent exploration. Afterwards, there are introduction of market research. Important parameters of ultrasonic anemometers are highlighted. Main aim of work is designing prototype of ultrasonic anemometer. Software, hardware and construct of experimental anemometer were designed. Created anemometer was calibrated in aerodynamics tunnel and results were compared with simulation output.

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