Journal des systèmes électriques et électroniques

Now a days the telecommunication systems have been concerned as a required for a life, the number of users are improved therefore the usage of spectrum are increased. From many different studies and researches very bad utilizations of spectrum were found. To solve it cognitive radio network is introduced in order to dynamic the spectrum therefore to increase the spectrum efficiency, decreasing costs and increasing number of wireless users, cognitive radio network solved bad utilizations and in advance it improved more characteristics for the spectrum. The goal of this paper is to identify along with clearly describe the concept of cognitive radio networks.

This paper explain how to determine the link budget design and receiver sensitivity design in term of bit error rate, BER and Q factor for different length and attenuation. The parameters which were taken into consideration of the simulation are network, type of coding, optical fiber length, attenuation, wave length, data rate, power detection, type of noise, type of modulator. The objective is achieved by using (OPTI system) and MATLAB software program, the results were obtained in terms of tables and charts.

With modern development, communication have become an important part of human life and cannot be dispensed with, the communication process involves information generation, transmission, reception and interpretation. Wide bandwidth for signal transmission with low delay is a key requirement in present day applications. Fiber optics is now the transmission medium of data for long distance and it has high data rate transmission for Telecommunication networks. This paper gives an overview of fiber optic communication systems including the concept of wire communication, characteristic, architecture, optical fiber system (link budget design) and application of fiber optic.

As solar energy is an important source of renewable energy resource. Sun radiation is being used as renewable energy, a combination of solar collector dish type and a Stirling engine is generally referred to the solar power. In this type, Stirling engine is depending on sunlight as source of heat to providing the input energy. This project presents different components and various configurations alongside with the feasibility of using solar energy as a source of heat for a Stirling engine. In addition to this, calculation of different components of Stirling engine and parabolic dish like sun heat calculations, Stirling torque calculations, generator calculations, and calculations for following and tracking the light intensity to get maximum solar power. This paper addresses issues which we saw during design and development of solar Stirling engine with generator to be sufficient acceptable for experimental and small wattage applications. This makes the energy usable in homes as a supplemental source of power or as an independent power source. 3D model is showing that is consisting of the parabolic collector, receiver, Stirling engine, and generator. The 3D model is prepared in solid work to enable us starting the manufacturing and calculations. The design is implemented to include location and depends on properties that affect the performance based on the sun elevation angle, ambient temperature, the wind speed, and density of air (altitude). Here experimental study is conducted on small-scale solar parabolic Stirling engine with generator. The solar collector is fabricated using satellite dish antenna fitted with polished sheets of aluminum. Low power is consumed to find the maximum power and highest light intensity. The applications of solar Stirling have green and clean energy generation from sun energy. Overall efficiency of solar Stirling power of system is expected to be around (36-24) percentage.