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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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Transmission of Digital Information over Audio
Bujnovský, Michael ; Malenovský, Vladimír (referee) ; Černocký, Jan (advisor)
Cílem této práce je umožnit přenést binární informace mezi dvěma zařízeními jen za pomocí zvuku. Práce začíná analýzou existujících řešení. Dále popisuje různé techniky digitální modulace, věnuje se synchronizaci a vlastnímu protokolu zapouzdřující data. Velkou částí práce jsou testy úspěšnosti přenosu za užití různých nastavení frekvencí a prostředí. Na základě výsledků testů je implementovaná uživatelská aplikace, umožňující demonstraci systému.
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Network with capacitor microphone using FM modulation
Lapáček, Petr ; Říha, Kamil (referee) ; Káňa, Ladislav (advisor)
In bachelor's thesis I was interested in quality of the electrostatic transducer. I have described a theoretic pieces of knowledges in parts of FM modulations and the variables crystals oscillators. I have tried to propose a conception of the condenser mikrophone in the high-frequency circuit where one of the main part was the crystal oscillator, which part was the capacitor transducer, in capacity element representative uncertain capacities. By this way I have tried to create the modulator, whose modulation depend on the actual changes of capacities in the electrostatic changers. Finally I have interested in the demodulation in this way of creating the HF signal by the help of detection unit TDA7000 and likewise setup of integrated circuit.
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Design of system for indication of gas leakage by ultrasonic microphone
Bohuš, Michal ; Kovář, Jan (referee) ; Šotner, Roman (advisor)
The aim of this project is detection of gass leak based on the ultrasound sensing. Work introduces ultrasound, mechanism of its propagation and attenuation. From all of the available microphones, the piezoelectric microphone was chosen. Project continues with description of the device, which can be capable of detection of the ultrasound leakage in dangerous, explosive environment. This type of device must meet requirements of SIL 2 standard and ATEX directive for zone 2. Project discusses LNA (Low Noise Amplifier), filters and detection circuits design. The device is modular what means that each module can be freely replaced. The role of these modules is to convert analog signal to digital form suitable for microcontroller HERCULES TSM57012.
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Acoustic sensor with ICP power and electronic datasheet
Dvorský, Pavel ; Klusáček, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The task of this Bachelor’s thesis is to introduce IEEE 1451.4 standard and connection of sensors with ICP supply to data acquisition systems. It deals with realization of acoustic pressure sensor (microphone) with ICP (CCLD) supply and possibility of saving real parameters of this sensor into transducer electronic datasheet (TEDS). Finally there is shortly described work with TEDS in LabVIEW programming environment.
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Localization of Combustion Engine Noise Origin with the use of Acoustic Emission
Rasch, František ; Mazůrek, Ivan (referee) ; Klíčník,, Martin (referee) ; Pražák, František (referee) ; Píštěk, Václav (advisor)
This doctoral thesis deals with the diagnostics of combustion engines, which have clearly suffered a mechanical damage. The text describes a basic principle of a diagnostics based on an observation of a noise of a running engine. There are mentioned the basic methods of a noise recording with direct conection to the specifics of measurement a running combustion engine noise. The introduction describes the spread of a vibration in solid structures. For the combustion engine vibration and source of noise is dedicated an independent chapter, which focuses on all noise generators, not only mechanical and thermodynamic but also noise caused by fluid and gas flowing. An integral part of the thesis is also a list and examples of signal processing, serving for efficient localization of the noise root cause. The noise statistics are compared with event diagram of engine investigation. Considering the information of the crank shaft position, we are then able to localize a possible root cause of the mechanical problem. For this purpose unique computer software for MS Windows operation system was developed. This system is able to generate event timelines of the piston engines. The inputs are basic engine data, such as the number of cylinders, ignition sequence, valve timing diagrams and information regarding two stroke or four stroke engine types. The program also allows us to detect a potential damage by direct comparison of the engine timeline and noise signal input. The thesis is also supplemented by measurements serving for key-parameter-diagnostics, i.e. the selection of the most suitable running engine operation. Comparison of different technical diagnostic approaches shows the suitability of mentioned diagnostic process.
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Measuring of pulse rate using smartphone
Víteček, Jiří ; Smital, Lukáš (referee) ; Němcová, Andrea (advisor)
This bachelor thesis deals with the possibility to measure heart rate using a smartphone. Today, many people own a smartphone. Newer devices can record various data thanks to its sensors and additional equipment. The current trend is to use the data so that the mobile phone can replace other devices, e.g. navigation, camera, camcorder or multimedia player. Recently, mobile phones have also been used in the field of medicine and, thanks to their mass extension, there is the potential to use them to detect health problems early on. With a functional mobile application, testing becomes cheap, fast, always available and easy to the general public. The beginning of the thesis describes the basic facts about physiology and anatomy of the heart, and circulatory system. Methods of heart rate monitoring using standard devices and smartphones, and measurement history are discussed as well. Two proposed methods using the smartphone's microphone and accelerometer are described below. For each method, testing and statistical evaluation are described. The thesis confirmed the possibility of using these methods for relatively accurate pulse rate measurement, even under different measuring conditions. Created applications with graphical user interfaces are described in the thesis including examples. The last part contains a comparison of methods, recommendations for measurement and final evaluation.
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Application for Measurement of Musical Instruments Directional Characteristics
Ustohalová, Iveta ; Orlovský, Kristián (referee) ; Mach, Václav (advisor)
This bachelor thesis is focused on the directional charateristics of acoustics music instruments measurements. Compilalation of measuring apparatus including microphone array and the individual steps of measurement and post-processing of audio recordings in *.wav format using program created in MATLAB and ment for this purpose is described. The output are graphs showing the directional charakteristics of selected instruments - violin, clarinet, guitar and accordion in selected one-third octave bands. The measurement results are interpreted and if available, compared with results given in literature.
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