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Audio Saving Module
Strašil, Ivo ; Kouřil, Jiří (referee) ; Říha, Kamil (advisor)
The aim of this thesis was to design and construct an autonomous, hardware voice recorder/player module. The device is made as a compact, built-in component for a motherboard of a target appliance. During recording, the incoming analog voice signal is converted to a digital stream by an ADC with 16 bits resolution and 24 kHz sample rate. Microcontroller LPC2103 (ARM7TDMI core) processes data, recalculates resolution and sample rate, encodes and converts to WAV format and save into a FAT/FAT32 filesystem on a Secure Digital memory card. At playback, the process is opposite: the microcontroller reads file from the memory card, decodes the stream and sends it to a DAC and then to a reconstruction filter. So there is an analog voice signal at the output again. The firmware allows control by logic inputs or by a serial bus, processing of uncompressed WAV files or WAV files with A-law or IMA ADPCM compression, continual recording including automatic freeing of card space by deleting the oldest records and a usage of a voice emphasis filter or of a signal dynamic compression circuit.
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Acoustic emissions of buildings
Smažinka, Josef ; Uher, Pavel (referee) ; Rubinová, Olga (advisor)
The diploma thesis deals with acoustics with the main focus on acoustic emissions of buildings. The first part of the thesis aims to familiarize the reader with the field of acoustics as a whole. They will learn the basic concepts, quantities and relations that exist in acoustics. In the second part I focus specifically on the sources of noise in buildings and their surroundings, how can excessive noise affect health, what standards must be met and how to prevent excessive noise. The last part is devoted to practical measurements in the field, which is focused on real sources of noise in the city of Brno. The aim of this measurement is to compare the noise generated by buildings with other noises in the urban environment.
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Monitoring of hydraulic machines using acoustic emissions
Závorka, Dalibor ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The goal of this diploma thesis is to clarify possibilities of usage of acoustic emission as a hydraulic machinery diagnostics tool. Especially for exposing presence of ruptures or cracks in the parts of machine, assuming changes in acoustic exposure of the part during operation. This clarification is based on series of simple measured experiments, which consist of monitoring the bolt placed in fluid stream inside of a pipe. This bolt was preloaded against inner wall of pipe by appropriate tightening torque. This preload is supposed to simulate effects of the size of rupture. High preload simulates small rupture or none in object and respectively small preload is supposed to simulate big rupture. A group of pressure sensors and accelerometers measures experiments and their evaluations are processed by script created in software MATLAB. Outputs of this script are charts with effective values of respective sensors from the entire record split into individual frequency spectrums. These charts compare spectrums of each configuration to judge effects of parameters changes.
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2x400W/8 ohms end amplifier
Káňa, Lukáš ; Balík, Miroslav (referee) ; Káňa, Ladislav (advisor)
Submitted text deals with a power amplifier intended for usage in music electronics. First part is related to the common problems of low-frequency amplifiers including principles and individual circuit wiring types. Next part is related to description of self-made power amplifier including wiring scheme diagram. The end of the text concerns about mechanical construction of mounting box and design of possible module layout inside a device.
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Software for simulation of acoustic pressure distribution
Hampl, Filip ; Schimmel, Jiří (referee) ; Kurc, David (advisor)
This semestral thesis deals with the creation of software to simulate the distribution of sound pressure. Basic principles of sound propagation are explained which are necessary for an understanding of the issue. There is a description of the velocity potential and its application in creating simulations. Another issue is the introduction of wavefield synthesis, which is essentially a technology for simulation of primary sources with secondary sources. Advantages of wavefiled synthesis are discussed as well as disadvantageous aspects. The practical part of this work is creating a user interface in Matlab, which allows user to plot the distribution of sound pressure of one or interaction of more emitters. Another possible outcome is to display the directional characteristics of real resources. At the very end of the work the direction of further work is outlined.
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System for Recording and Repeating of Events for Sound Systems
Klobása, Jiří ; Černocký, Jan (referee) ; Zemčík, Pavel (advisor)
This thesis deals with the design and implementation of system for recording and repeating of events for audio systems. The introductory part is devoted to the study of sound systems, their user interfaces and communication protocols that are used by audio systems. Hereafter the description of essential features of Mac OS X, as well as the characteristic of its user interface and principles of development on this platform, are given. The core of the thesis consists of the design of system for recording and repeating of events and the concept of events which specifies the reprezentation of events in the system and their subsequent processing. In~the end of the thesis is presented the implementation of the designed system for Mac OS X with respect to possible extensions of the system and its features.
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Study of acoustic properties of enclosed rooms
Kovařík, Filip ; Fišarová, Zuzana (referee) ; Šťastník, Stanislav (advisor)
The bachelor thesis deals with the acoustics of enclosed spaces, its behaviour and impact on the clarity and quality of presentation. Here is written transmission of acoustic energy, behaviour of spatial and building acoustics, which builds their diagnostic methods. The work also includes legislative requirements stipulated by the acoustics of enclosed spaces and the achievement of these requirements using different types of acoustic absorption capacity of materials, applications, and more specifically their basic properties. In the experimental part, the measurement of reverberation time in a selected room and the adaptation of acoustic properties so that attained legislative requirements
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Complete design of three-way speakers
Jalový, Michal ; Petržela, Jiří (referee) ; Slezák, Josef (advisor)
This project describes complete design of Three-way speakers. The introduction discussed the basic theoretical knowledge to the understanding of loudspeaker system design issues with regard to the physiology of hearing, the theory of acoustics, speaker characteristics, types of enclosures and the use of switches. Furthermore, based on the formula calculated parameters of a loudspeaker cabinet and speaker points to the loudspeaker of the proposed speakers.The proposal also relies on the specific measurement properties of the selected speaker impedance. Finally all data are presented for practical implementation speakers.
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Player for iPhone for Educational Purposes
Klobása, Jiří ; Polok, Lukáš (referee) ; Beran, Vítězslav (advisor)
This thesis deals with the design and implementation of mobile application for iPhone that serves as a music player. The application works with meta-information to a music song and suggests their use in the process of memorization. The thesis is divided into chapters, starting with the characteristics of the target platform iOS, user interface design and its testing, principles of creating computer music and sound. The core of this thesis is to design a user interface along with the structure and use of meta-information related to a song. At the end of the thesis there is described the implementation of the application, the tests performed and possibilities for further improvements of the application.
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Soundspce
Jandová, Eva ; Kopec, Jakub (referee) ; Vítek, Jiří (advisor)
The aim of this work is to research the relationships between abstract musical space and physical space, to explore the various possibilities of connecting sound, light and matter in space, their interaction and unfolding over time. The knowledge and outputs will later be applied in the design of a cultural object providing a visual and acoustic experience with an emphasis on human perception.
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