Disertační práce se zabývá optickým digitálně-analogovým převodníkem, jako alternativou optické části koncové vysílací jednotky (optický front-end) určené pro VLC (visible light communication) aplikace. Stěžejní část práce, která se věnuje numerickému modelování optického kanálu, prezentuje vliv bitové hloubky, topologie koncové části optického vysílače a geometrického uspořádání na přenášený signál. Součástí práce je návrh, realizace a ověření parametrů optického digitálně-analogového převodníku vycházející z předcházejících simulací. V poslední řadě práce obsahuje demonstraci vysokorychlostní optické komunikace s využitím navrženého VLC optického vysílače.

Master's thesis treat of optical connection. The aim of this work was also the practical implementation and successful testing. Communications signal is low frequency in the range of 20 to 15 kHz and intended length of the coupling is approximately 200 m. The first is the work carried out theoretical analysis issues. Then is described the design and implementation of its own facility. In conclusion, the measurement is done and evaluate the parameters. I have dealt the optical connection with using a laser beam that is modulated frequency modulation. This optical signal is converted in the receiver using a PIN photodiode (type PIN) back to the electrical signal. Then there is the demodulation and amplification. The frequency modulator and demodulator is phase lock loop. It realizes the type of circuit CMOS 4046. The work is designed properly functioning equipment. It serves for the transmission of speech and audio signal line. It has good properties that match the criteria. The connection can be used outdoors due to the use of cover. The scope of communication may be even greater than 200 meters

This dissertation thesis deals with a long range free space optical links for communication over the distance of few tens of kilometers in the atmosphere. The problematic of the beam propagation and atmospheric effects influencing the beam and the quality of the communication protocol are discussed. The measuring link is also designed to study the parameters of the communication link work conditions. The measuring link consists of two heads. The transmitter head is designed to use two optical beams with laser diodes at the wavelength of the atmospheric windows 850 or 1550 nm and the overall power of hundredths of mW. The receiver head includes the Fressnel lens. For the detection of very weak signal, the avalanche photodiode is used. In the end of this work, due to the high power of the transmitting optical beam, the laser safety conditions are also discussed, including the deduced optical transmitters construction recommendations.

This work is focused on free space optical communication in visible electromagnetic spectrum known as visible light communication (VLC). Basic parameters of standard IEEE 802.15.7, advantages and disadvantages are discussed in the theoretical part of this work. Furthermore, optical link and it´s parts are described. The largest part of the work is focused on design and simulation of optical receiver for visible spectrum. Selection of component, noise and SNR calculation is discussed as well. This work also includes calculation of power energy in different parts of optical connection, PCB design of optical receiver, transmitters and power supply and output board. Behavior and parameters of electronic circuits, components and optical connection are explored, measured and compared with theoretical values.

The aim of the study was focused on problem of electrograms recording from alive tissue. Study of electrograms recording was extended with noise analysis and its elimination. Elimination of noise and disturption was made in program Matlab; lowpass filtration and wavelet transformation was used. Application for electrograms analysis was developed in latter part of this work.

This thesis deals with method of measuring optical beam intensity, searching for communication system beam using stepper motor movement of the optical head and processing measured signal for displaying on PC. The basic theory of optoelectronics is shown here concerning the problem. There is elaborated main principles of photodetector and stepper motor mainly, which are main part of device. The second part of work is theoretical design of data recorder. All parts are described individually-their characteristics and conditions for correct usage. In the last part setup of device is explained, with the references to blocks of written programs. In the last part, main funcrions of system, its hardware managing and communication are described. At the very end of thesis, examples of measured data are presented.

This diploma thesis is focused on design and prototyping of wireless optical link for an indoor usage. In the beginning of the thesis frequency spectrums of infrared, visible and ultraviolet light are described by its typical qualities such as values of attenuation or reflection capability. On the basis of this analysis, a proper wavelength has been chosen for usage at the engineered communication system. Next part is devoted to selection of suitable communication components on basis of its declared qualities. In the following chapter this qualities are in carefully measured and after that they are compared with values provided by its manufacturer. The following section is devoted to design schemes of transceiver modules. After completion of the design the manufacturing of PCB, mounting components and the analysis of their distribution was described. The last part of this thesis deals with testing of created prototype in terms of maximum transmission distances and operating frequencies. At the very end of this project, in one small section ways to improve system characteristics was discussed.

The diploma thesis deals with design of the converter card for the precise control of a laser diode. At first, there are described the principles of the laser diode, photodiode and basic functions of optical fiber sensors. Following chapter deals with description of developed converter card. In the diploma thesis are discussed all function blocks of the converter card and they are explained in detail. In the thesis are subsequently tested all problem parts of the converter card for the precise control of the laser diode, such as fast switching of the current flowing through the laser diode and design of the connection for evaluating of current pulse from the sensing photodiode. An integral part of thesis is a description of created printed circuit board and there are described all used layers and devices’ layout on the PCB. Final part of the diploma thesis deals with firmware for the microcontroller, which was made for testing of all function blocks of the converter card for the precise control of a laser diode. At the same time was developed software for PC, which communicates with the converter card via universal serial bus (USB).

The diploma thesis deals with description and design of a low-cost free-space optical (FSO) link. First, general FSO theory is discussed including their common parameters, properties and topologies. Further, optical signal sources and detectors are proposed. Finally, the selected implementation is described including its design and realization. The proposed FSO consists of two identical segments (modules) to form a full-duplex link. The FSO utilizes LED as a light source, maximum speed data rate is 100 Mb/s with 100Base-TX interface.

The aim of the study was focused on problem of electrograms recording with using voltage sensitive dyes. Study of electrograms recording was extended with thema of optical detectors suitable for measurement and noise analysis. Elimination of noise and disturption was made in program Matlab; lowpass filtration and wavelet transformation was used. Application for electrograms analysis was developed in latter part of this work.