The subject matter of the paper is the processes of analysis and evaluation of the effectiveness of information coding methods in wireless systems. The aim is to improve noise immunity of information messages under conditions of powerful electromagnetic interference, with the help of complex signal-code constructions. The objective is to develop a method for noise-immune encoding in a wireless information transmission system, providing increase in information transmission rate. The methods used: Simulation and digital signal coding. The following results have been obtained: A method for encoding information transmitted via wireless communication lines in presence of interference. For signal coding, it is proposed to use Gaussian monocycle with time-dependent position-pulse modulation (PPM). It is shown that for organization of independent channels within a single frequency band, it is practical to use a system of orthogonal codes. Pulses of the useful information signal accumulated in a receiver correlator provide significantly increase in signal-to-noise ratio, allowing transmission of information over a wide frequency range well below the noise level. As a result of encoding information in wireless information transmission systems with the help of ultra-short pulse signals, the effectiveness of the proposed method is a quantitatively and qualitatively evaluated. Conclusion. Using Pulse Position Modulation coding in wireless information transmission systems allows transmitting large volumes of information with high transmission rate and high noise immunity of the communication channel as well as protecting the channel from message interception. Ability to work with low radiating power and high signal capacity to penetrate various obstacles ensure fulfilment of electromagnetic compatibility requirements as well as stable communication in conditions of multipath radio wave propagation. A possibility that powerful electromagnetic disturbances accompanying a lightning discharge may have catastrophic impact on the information transmission channel is also eliminated. K e ywor d s : wireless communication line; information coding method; time-dependent position-pulse modulation; lightning discharge; electromagnetic compatibility; electromagnetic interference.

The subject matter is the mechanisms of emergence of instabilities in natural oscillations of semiconductor supertattices caused by their interaction with charged particle flows of extraneous electromagnetic radiation. The aim is calculating ratios to determine a degree of deviation of operating characteristics of semiconductor components from the norm, depending on the parameters of extraneous pulsed electromagnetic radiation. The objective is to model how currents that are induced with extraneous EMR interact with electrostatic oscillations of a semiconductor supertattice, using an implementation of (Cherenkov) resonance interaction of moving charges with electromagnetic oscillations under conditions where the phase velocity of the wave and the velocity of the charged particle are the same. The methods used: analytical methods for solving Maxwell's equations and medium equations in a framework of hydrodynamic approach. The following results are obtained. We have studied semiconductor components of electronic equipment (supertattices) being exposed to strong pulsed electromagnetic fields. The study was focused on the nature of changes in the working capacity of the components. We show that the effect of pulsed electromagnetic radiation is accompanied by an emergence of currents in the conductive hardware elements and an emergence of internal fields within them. One kind of reversible failures of semiconductor hardware elements is determined, based on interaction of extraneous radiation induced currents with the intrinsic fields of the supertattices of the hardware components. Similar failures occur under conditions of Cerenkov radiation (when the current is parallel to the structure boundary). It is shown that such interaction leads to energy losses in the induced currents spent to excitation of natural oscillations of the supertattice, i.e. to emergence of an oscillation generation mode that is characterized with a change in the volt-ampere characteristics of the hardware. Conclusion. The results obtained in this work can be used to evaluate the efficiency of active radio electronic devices (amplifiers, generators and converters of electromagnetic oscillations in the millimeter and sub-millimeter ranges) being exposed to extraneous pulsed electromagnetic fields. The comparative analysis of quantitative evaluations of reversible failures of semiconductor devices in dependence on the spatial configuration of the acting field (induced current parallel to the structure boundary) allows solving problems in optimizing the degree of distortion of the performance characteristics of these devices.

The subject matter is analysis and evaluation of efficiency of noise-like signals in wireless information transmission systems. The aim is quality of service improvement for mobile subscribers, due to communication channel multiplexing using complex signal-code structures. The objective is development of a systemic view of the technology of information transmission using ultra-short pulse signals focusing on main phenomena that arise at different stages of signal transmission in a wireless information transmission system. The methods use dare sequential analysis, simulation modeling and digital signal coding. The following results have been obtained. An antenna design featuring an expanding slit has been proposed for effective emission and reception of noise-like signals. A method for controlling radiation pattern of such antenna array has been developed. Gaussian Monocycle coding of information with time position-pulse modulation has been justified to be used as a noise-like signal. It has been shown that for the organization of independent channels in one frequency band, it is practical to use a system of orthogonal codes, e.g. Walsh sequence. Due to accumulation of pulses of a useful information signal in the receiver correlator, significant increase in signal-to-noise ratio becomes possible, which enables information transmission over a wide frequency range well below the noise level. As a result, a systematic understanding of the technology of information transmission using ultra-short pulse signals in wireless information transmission systems is developed and a quantitative evaluation of the efficiency of the proposed technical solutions is provided. Conclusion. The use of noise-like signals in wireless information transmission systems provides for high data transmission rates with high interference immunity and tapping protection communication channel. The ability to operate with low emitted power and the high penetrability of noise-like signals through various obstacles, for example, walls, allow meeting the requirements for electromagnetic compatibility and ensuring stable communication in conditions of multipath propagation of radio waves. These circumstances form the basis for the development and implementation of information transfer technology using noise-like signals when designing office networks.K e ywor d s : noise-like signal; wireless information transmission system; time position-pulse modulation; orthogonal coding; electromagnetic compatibility.

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The subject of the study are processes of manifestation of instabilities of natural oscillations of semiconductor structures, which are caused by the mechanisms of interaction of charged particle flows in the presence of powerful external electromagnetic radiation. The goal is to obtain design relationships that allow determining the degree of deviation of the performance characteristics of semiconductor components from the norm, depending on the parameters of the external pulsed electromagnetic field. The task is to construct a model of interaction induced by external electromagnetic radiation currents with electrostatic oscillations of the semiconductor structure. The model is based on the realization of the resonance (Cherenkov) interaction of moving charges and electromagnetic oscillations under conditions where the phase velocity of the wave and the velocity of the charged particle are the same. The methods used: analytical methods for solving the Maxwell equations and the equations of the medium in the framework of the hydrodynamic approach. The following results are obtained. Investigations of the functioning of semiconductor components of electronic equipment under the influence of strong-pulsed electromagnetic fields are carried out. The nature of changes in the working capacity of semiconductor components of the hardware component base is determined. It is shown that the influence of pulsed electromagnetic radiation is accompanied by the appearance of currents in the conductive elements of products and the appearance of intrinsic internal fields. One of the types of reversible failures of the semiconductor element base of electronic products is determined, based on the interaction of currents induced by external radiation with the intrinsic fields of the structures that complete the product. Similar failures are realized under conditions of Cherenkov radiation, when the current is parallel to the boundary of the structure. It is shown that this interaction leads to energy losses of the induced currents to excitation of the natural vibrations of the structure, i.e. the appearance of a mode of oscillation generation, which is characterized by a change in the volt-ampere characteristics of radio products. Conclusions. The comparative analysis of quantitative evaluations of reversible failures of semiconductor devices depending on the spatial configuration of the acting field, in which the induced current is paralleled to the structure boundary, allows solving problems of optimizing the degree of distortion of the performance characteristics of these devices. The results obtained in the work can be used to evaluate the efficiency of active radioelectronic devices, for example, amplifiers, generators and converters of electromagnetic oscillations in the millimeter and submillimeter ranges under the influence of powerful external pulsed electromagnetic fields.