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Tube Microphone
Škoda, Adam ; Šotner, Roman (referee) ; Staněk, Miroslav (advisor)
The presented thesis deals with a tube microphone using a condenser microphone capsule for sound capturing. Moreover, two essential aspects of a tube microphone – the basis of its operation and its design – are also discussed in this thesis. In the designed microphone, there is a vacuum tube known as ECC81. This vacuum tube is used as an amplifying element of an input sound signal. This paper also includes the choice of the most suitable microphone circuit, its modification and the design of a voltage source used for feeding and heating the vacuum tube. Some appropriate simulations were applied to find out the functionality of all designed parts of the microphone system. Following step was the practical realization of all microphone parts as well as the activation and the complete parameters and characteristics measurements of realized microphone system. After the provided measurements, the microphone was compared to equivalent commercial products. Evidently, the realized microphone is qualitatively similar to other commercial products. Presented thesis also contains the list of components and PCBs.
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Spectral analysis of sound in spatial acoustics
Křenek, Jakub ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
This thesis is focused on the basics concepts of room acoustics and used sound level meters. The first part focuses on the spatial acoustics and acoustic quantities used in it. Next part of thesis describe the structure and features of sound level meters. Following chapters are concerned on the PULSE system architecture and data analysis. PULSE platform contributes multi-spectral analyzer type 3560B PULSE, programming environment LabShop and microphones for difuse and free fields. The practical part describes the installation, setup and the measurement of reverberation time in the Labshop environment.
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Hybrid microphone preamplifier with variable selection of amplifier technology
Musil, Tomáš ; Levek, Vladimír (referee) ; Háze, Jiří (advisor)
This diploma thesis deals with a basic description of dynamic and condenser microphone, its performance regarding polar patterns and a type of mechanical construction. It also describes a principle of operation of a triode. The thesis deals with selecting of a suitable type of microprocessor to control microphone preamplifier functions. Last part contains a power supply and microphone preamplifier circuits design using a semiconductor and vacuum tube technology.
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Measurement of the rain rate instantaneous value using acoustic method
Kresta, Daniel ; Poliak, Juraj (referee) ; Wilfert, Otakar (advisor)
This thesis deals with implementation of the rainfall rate measurement using an acoustic method. It is divided into four parts. In the first part of the thesis a necessary theoretical knowledge is analysed. The second part contains a design of a workplace used for the measurement. The third part presents and analyses important experimental recordings acquired in the workplace. Then all measured values are processed and applied in the measuring program. The last part summarizes results of the thesis, advantages and disadvantages of using the acoustic rainfall rate meter.
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Measurement and analysis of phonocardiographic signal
Všetula, Petr ; Kolářová, Jana (referee) ; Kolář, Radim (advisor)
This work is engaged in measurning and analysis of phonocardiographic signal. Effect of characteristics and parameters of used parts is examined due to quality of measurement of these signals. The emphasis is put especially on the amplifiers and microphones. The measurment is done by measure card PCI6221E. Data processing and analysis is proceeding by the help programmes, which are created in programmatic environmen LabView.
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Noise Source Identification Using Beamforming
Kurc, David ; Míča, Ivan (referee) ; Schimmel, Jiří (advisor)
This master's thesis is focused on the noise source identification using microphone arrays and beamforming as the signal processing method. It describes parts of such a system and provides a comparison with other systems that serve a similar purpose (eg. NAH). Various types of microphone arrays are mentioned with their influence on the resulting ability to identify the noise source. We are further focusing on Delay-And-Sum technology, on which we are explaining the basic principles and constraints of beamforming. The practical part describes the implementation of the DAS method in MATLAB and C language, the specific structures of built microphone arrays and assembly of complete systems capable of identifying sources of noise. These systems were tested by performing a practical experiment. Achievements in the form of distribution maps of acoustic energy in the focused space are interpreted in the last chapter.
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Spectral analyse of sound in space acoustics
Port, Martin ; Bereznanin, Martin (referee) ; Rozman, Jiří (advisor)
This thesis is an introduction to the problems of acoustics and is focused on the variables describing the noise. The methodology for measuring noise in relation with valid hygiene standards is analyzed in next section. The noise levels at work required by government regulation no. 148/2006 are summarized in a subsequent charter. The next section is an introduction to the analyzer PULSE 3560B from Brüel & Kjar. This work describes a software called Labshop, which is designed to analyze noise and vibrations. It also describes the most common features Acoustilyzer NTI AL1. The practical part was to measure the reverberation, noise, frequency spectrum and plott the distribution of noise with noise maps of various auditoriums.
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Non-destructive Detection Methods of Biological Activities Wood-destroying Insects
Kintr, Jindřich ; Král, Bohumil (referee) ; Fiala, Pavel (advisor)
The subject of this thesis is to study a non destructive methods and methodologies of detection biological wood pests. Analyzed method of detection in this thesis is non destructive acoustic detection. For scanning the activity of wood pests a sensor with piezoelectric converter is used and for scanning the ambient sound a sensor with an electret microphone is used. The signals from these sensors are subtracted in a differential amplifier. In this thesis we can find a method determine the similarity of two signals and a laboratory measuring of detection of activity of a wood pests (Hylotrupes bajulus).
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