Today, users of radio frequencies face a double challenge, namely: - Respond to a growing need for communication channels (frequencies); - Maintain good quality of service (Qos). The difficulty results from the fact that the number of frequency (channels) available for radio electricity spectrum allocation is a very limited resource. This constraint imposes optimal and efficient use of frequencies, taking into account all the necessary parameters so as not to increase the probability of interference and also to avoid the malfunction of neigh boring stations. In the Democratic Republic of Congo in general and more particularly the city Province of Kinshasa, the Post and Telecommunications Regulatory Authority of Congo (ARTPC) has a limited number of usable frequencies in order to cover the needs of potential users.

In this article we will try to study the motion of a charged particle electro dynamic. Note that a moving charged particle finds its application in electronics, more precisely in television and the vacuum tube, thus giving rise to the different types of screen currently used to display an image of a transmitted object. Note that a moving charged particle is subject to two fields: the electric field □( (E ⃑ )) and the magnetic fiel□( (H ⃑ )) . This article will be the subject of a study in uniform electric field taking into account the physics laboratory reference of the department of physics and applied sciences of the National Pedagogical University. For this purpose, we used for our experiment: - Two metal plaques ; - An electron gun having a cathode et anode ; - A low and high voltage generator ; - A screen (flat surface for projecting light). The objective of this study is to establish the different equations of motion of a charged particle an uniform electric field E in a projection frame (O:i,j,k). To close the study, we will finally consider the electrical bending of a charged particle moving between two plaques having different potentials.

In this article, it is a question of studying the behavior of a band pass filter in BF and HF with passive elements. Said filter is widely used in electronics and telecommunications with many applications such as: manufacture and assembly of loudspeakers, limitations of working frequencies in a given interval according to its band, etc. We preferred to do this study based on mathematical and physical models which allowed us to discuss and interpret the different results obtained after simulation at the physics laboratory of the National Pedagogical University (UPN/RDCongo-Kinshasa) and which are presented as follows: In Low Frequency (BF): The capacitor blocked the signal and behaved like an open switch, on the other hand the coil allowed the signal to pass through. It acted as a closed switch. Therefore, the voltage at the filter output was zero; In High Frequency (HF): We had the opposite behavior in BF and the voltage at the output of the filter was always zero. The studied behavior led us to the determination of the band pass filter. The tool used for the simulation in Matlab, very powerful engineering software.

The modeling of an interconnecting network with optical fiber aimed to be represented by taking into account some phenomena (characters, forecasting, etc) with the help of mathematical equations or formula. In general way, the simulation of the later enables us to create a virtual laboratory with the help of Matrix Laboratory Software (Matlab) with the possibility of doing the tests at cheaper cost for the benefit of considerable time in relationship with the implementation of macroscopic trial at laboratory.