This thesis discusses about using the worldwide satellite system GPS for time and frequency synchronization. This thesis presents study about basic principles of the GPS system, its segments and ways of using this system. Some GPS receivers suitable for receiving the time marks (pulses) used for time synchronization are described. Thesis contents designing of the circuit that will receive time marks and it will digitalize and record external signal and send it with precision time information to PC for displaying and post processing. Thesis also discusses about both hardware and software development of the synchronization module and software used in PC.

In last years phenomena of wireless communication technologies became a primary interest of big development laboratories whole world. Domain of point to point links which are realized by laser technology with narrow beam divergence and very sensitive photo-detectors is ordinarily used these days. This trend of using light waves as carrier medium turned interests of scientist to the sphere of wide area networks which is domain of wi-fi radio technologies. One of new trends in this sphere is also in-door free space optics. With expansion which leads to using LED's in everyday applications and with technological progress of last years, also grows tendency of most effective utilization of LED systems. The result of this effort is thought which considerate LED as source of artificial lighting and source of carrier medium for modulated signal. This kind of device must fulfill hygienic standards for illumination and also must be able to work with high frequency by which is signal modulated. These systems can provide links with sufficient capacity in order of hundred megabits.