Andriy Semenov

The Van der Pol's mathematical model of the voltage-controlled oscillator based on a transistor structure with negative resistance

The results of the mathematical modelling for the voltage-controlled oscillator based on a transistor structure with negative resistance are presented in this article. The generated oscillations with and without noise were described with the Van der Pols model. The research was carried out for relaxation and oscillator modes of the generator.

Reviewing the mathemetical models and electrical circuits of deterministic chaos transistor oscillators

In the paper, the wide-spread mathematical models of the deterministic chaos transistor oscillators are considered. These models describe dynamic processes to take place in transistor Colpitts oscillators. Variations of the deterministic chaos transistor oscillators schemes are presented. Phase portraits, time and spectral diagrams of chaotic oscillation were obtained.

Mathematical simulation of the chaotic oscillator based on a field-effect transistor structure with negative resistance

In this paper a classical circuit of the Kiyashko-Pikovsky-Rabinovich deterministic chaos oscillator based on a field-effect transistor structure with negative resistance got the further development. The chaotic oscillation dynamic processes in this oscillator have been researched using the improved model. Phase portraits of the oscillator in different operating modes have been obtained.

The UHF oscillators based on a HEMT structure with negative conductivity

The article considers a possibility of constructing microwave oscillators on a transistor structure with negative conductivity based on two HEMT. Obtained non-linear equations can be used to model microwave oscillator parameters and characteristics with an error not more than 10%.

Access fuzzy controller for CDMA networks

It is suggested to use a fuzzy-neural controller for access control in CDMA networks that allows avoiding congestion in networks. The fuzzy-controller for controlling users access has been designed. Linguistic variables, terms and membership functions for input and output values have been defined. A rule base has been developed.

Routing in telecommunication networks using fuzzy logic

In the paper it has been proposed to use a fuzzy-controller in telecommunication networks for improving the routing process. An architecture of the fuzzy-controller was developed. Linguistic variables, terms and membership functions for input and output values have been defined. Rules base has been developed. The operation of the fuzzy-controller has been simulated.

Experimental research and simulation of microwave oscillator based on structure of static inductance transistor with negative resistance

The experimental research of characteristics of the microwave oscillator based on the structure of static inductance transistor has been carried out and the model of its static and dynamic current-voltage characteristics has been improved. The results of the experimental research show that oscillating frequency changes from 770 to 900MHz, amplitude of generate oscillations changes from 5 to 22 V, average power of oscillations is 96mW, coefficient of efficiency is 80-85% when supply voltage variation is from 9 to 30 V. Calculation of characteristics by means of the simplified charge model of the structure of static inductance transistor gives quite accurate description of characteristics of the active element of the oscillator.

Radiofrequency deterministic chaos oscillator based on a transistor structure with negative resistance. Numerical researching

The deterministic chaos mode in a basic circuit of a radiofrequency oscillator based on a bipolar transistor structure with negative resistance have been studied in this paper. Experimental research results for parameters and characteristics of the bipolar transistor structure with negative resistance have been obtained. Chaotic dynamics of the generated oscillation has been explored. Feasibility of connecting a symmetrical dipole antenna to create a transmitter with chaotic carrier has been estimated.

Mathematical model of the microelectronic oscillator based on the BJT-MOSFET structure with negative differential resistance

The paper considers an electric circuit of a microelectronic oscillator based on a BJT-MOSFET structure with negative differential resistance. A mathematical model of this oscillator has been developed. Theoretical and practical researches of oscillations dynamics have been carried out. Lyapunov exponents have been calculated. Limits of periodic and chaotic oscillations modes have been determined. Phase portraits, time and frequency dependences of oscillations have been obtained.

The neuro-fuzzy controller for handover operation in mobile networks

The paper proposes using a neuro-fuzzy controller in mobile networks for improving the handover process. An architecture of the neuro-fuzzy controller was developed. Linguistic variables, terms and membership functions for input and output values were defined. A rules base was developed. The operation of the neuro-fuzzy controller was simulated and trained.