Information interchange in modern pilotless vehicles’ control complexes
Vilkova N.N., Evstigneev V.G., SuKhachev A.B.
Modern pilotless complexes possess a high maneuverability and sufficient equipment means of monitoring of a spreading surface that allows to use them for the decision of the broad audience of problems both special, and economic value.
Key words: pilotless flying device, pilotless complex, useful loading, devices of gathering of the specific information.
Analyzing narrow-band interference suppression methods on receiving ultrawide-band signals
Kosichkina T.P., Speransky V.S.
Powerful narrowband interference can corrupt ultrawideband (UWB) radio transmission. For rejection of this interference some methods are employed. This paper presents nonlinear processing methods for short-pulse UWB technology. The system with one-cannel and multi-channel Fourier transformer with limiter, are investigated. The system used Direct Sequence Phase Coded UWB (DSC-UWB) modulation to encode data are modeled. Efficiency of processing estimated with correlation function peak and side lobes reduction. The results show that using a multi-channel Fourier transformer without adaptation limiter lever has better system performance than other methods. The paper contains also recommendation for choosing limiter lever.
Key words: UWB, ultrawideband systems, narrowband interference, limiter, multi-channel processing, nonlinear processing, Fourier transformer.
OFDM carrier recovery under short-term frequency-selective fading conditions
Kazakov L.N., Markov K.A., Ismailov A.V.
The investigation of the complex non-data-aided OFDM carrier recovery algorithm was presented. The offered algorithms include the phase-locked and the multitude-locked loops with QAM-detector based on ML theory. There is the presented method are compared with basic pilot-based compensations scheme.
Key words: OFDM, short-term fading, frequency-selective fading, non-data-aided ML estimation, multitude and phase correction.
Methods of estimating random signals’ parameters under prior uncertainty
The 2 estimation methods of continuous phase modulated signal’s delay, phase and frequency in presence of an additive noise with an unknown distribution law are shown in this article. The estimations were analyzed with nonlinear filtration and nonlinear equations’ system decision methods. PC simulations showed the algorithm based on the nonlinear equations’ system decision method required less sample size rather than the algorithm based on the nonlinear filtration method in condition to achieve the satisfactory precision for the signal parameters’ estimation.
Key words: algorithm, method, expected uncertainty, model, functional, estimate, nonlinear filtration, system of nonlinear equations.
Investigating cellular system’s mobile terminals’ radio receiving path stations
Pestryakov A.V., Makarov E.V.
The signal with sophisticated types of modulation take a wide spread place in the current digital telecommunication networks. The processing, transmit and generation of such signals form their distortion. The sources of distortions excluding the radio channel ones are the non-ideal (non-linear) radoitransmitter and radioreceiver path’s nodes functionalities. An analytic math studies of such processes are difficult to be processed using the latest math methods because of not only sophisticated structure of used signals and distortions in mobile cellular networks, but there are difficulties to think the math description and study of processes describing the non-linear effect formed by radioreceiver path’s nodes. So such difficulties lead to use the computer simulation for non-linear effects of described nodes. The computer simulation studies of non-linear effects in the radioreceiver path designed as direct conversion receiver helped to get the restrictions for values which are describing the nodes works on radioreceiver antijamming ability. The obtained data forms the requisitions on maximal values of the distortions for any node. The dependencies can be approximated with necessary precisions and they can be used for education and modeling purposes. This data can be used to radio component selection during a radioreceiver design.
Impulse noise suppression in rank-order filtration based images
Priorov A.L., Khryashchev V.V., Kuykin D.K.
In this paper the improvement of SPIHT algorithm and JPEG2000 algorithm by adaptive wavelet filters changing is proposed. The main difference of modified algorithm from classic one consists in first-level wavelet transform synthesis filters impulse response modification. The method based on searching for the impulse response of desired length, which allows getting maximum improvement of the image quality.
Key words: image compression, discrete wavelet transform, impulse response changing, SPIHT, PSNR.
Experimental investigation of PM-noise in CMOS-inverter based oscillators
Zabin A.S., Kuleshov V.N.
CMOS-structures are widely used in communication systems. They are used to build some important parts of frequency synthesizers: frequency dividers, phase-frequency discriminators, quartz crystal oscillators and voltage controlled oscillators. In modern communication systems rather strict requirements to PM-noise of oscillators and frequency synthesizers are established. To forecast PM-noises, introduced by circuits with CMOS-structures, one needs the CMOS-structures models that could be used to calculate these noises. In this paper rather simple CMOS-inverter model, containing internal source of PM-noise, is offered. A method of this PM-noise measurement, based on investigation of test-oscillator PM-noise, is also presented. The estimation of power spectral density of 1/f noise, introduced by the CMOS-inverter under investigation, presents opportunities to forecast PM-noise levels of different oscillators and other circuits, containing this type of CMOS-inverter.
Key words: CMOS-inverter, PM-noise, oscillators, experimental investigation, gross level model.
Bipolar transistored differential buffer amplifier’s phase noises
Boldyreva T.I., Vasiliev M.V.
Results of theoretical analysis of PM and AM noise introduced by BJT resonance differential amplifiers are presented. Both wideband and 1/f PM noise is calculated. An influence of the amplifier input impedance fluctuations on PM noise of oscillator connected with the amplifier input is investigated. Some recommendations related to choosing parameters of buffer differential amplifiers that are used in low noise frequency sources are formulated.
Selection of compatible radio-frequency channels
Prikhodko V.V., Panov V.P.
Formulas of selection of the compatible radiofrequency channels groups for location on the object up to seven radioelectronic equipments are obtained. These channels provide of frequency wigging of unwanted components up seventh power forming in result of nonlinear processes in the elements of transceiver links and introduced in the manner of given linear combinations of few frequencies. Use of these formulas gives advantages in contrast with known methods so as simplifies solution similar problems.
Multipath communication channel characteristics definition routine
The method of an estimation of intensity and phase of beams of the multibeam communication channel based on measurement on pilot frequencies of its complex transmission ratio is presented. Influence of quantity of pilot frequencies and the frequency separation between them at which high accuracy of an estimation of a frequency response of the multibeam channel in a wide frequency band is reached is investigated. Results of investigation can be used at synthesis of an optimum equalizer of an intersymbol interference in the multibeam channel.
Errors multiplicity function determination in transient channels
The method of errors multiplicity function calculation in transient channel is offered. It is based on joint using error-generating function and Monte-Carlo method, that lets to calculate error spectrum for different statistic description at the same time. The generation of the channel parameter vector is offered by making fast orthogonal frequency spectrum transform.
Communication channel signal detection method
The communication channel call signal detection method based on the Neumann-Pierson criterion is examined to find a threshold value for decision making. The signal and noise power calculation technique based on call signal transmission through matched and orthogonal filters is proposed.
Key words: digital signal processin, signal sensing, matched filtering, Neumann-Pierson сriterion, pseudorandom sequences.
Application of security software’s modeling algorithms
This article presents most common and widely used at the moment methods of modeling software’s behavior. Advantages and disadvantages of each one are concerned. The way of upgrading these methods is proposed. The results of using each method are applied.
Key words: behavior models, deflections.
Mathematical rationale for increasing telecommunication equipment’s efficiency due to flexible tariffs.
Rakhimov T.G., Sokolov V.K., Belova L.N.
Absolutely crypto secure and elementary encoders.