Journal articles: 'Telecommunication systems – Noise'

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Kropotov, Y. A., A. A. Belov, and A. Y. Prockuryakov. "Increasing signal/acoustic interference ratio in telecommunications audio exchange by adaptive filtering methods." Information Technology and Nanotechnology, no. 2416 (2019): 271–76. http://dx.doi.org/10.18287/1613-0073-2019-2416-271-276.

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The paper deals with the issues of increasing signal/noise ratio in telecommunication audio exchange systems. The study of characteristics of speech signals and acoustic noises, such as mathematical expectation, dispersion, relative intensity of acoustic speech signals and various types of acoustic noises and interference is carried out. It is shown that in the design of telecommunications systems, in particular loudspeaker systems operating under the influence of external acoustic noise of high intensity, it is necessary to solve the problem of developing algorithms to effectively suppress the above mentioned interference to ensure the necessary signal/noise ratio in communication systems. A mathematical model of the autocorrelation function of the speech signal by using the Lagrange interpolation polynomial of order 10, considered the creation of adaptive algorithms to suppress acoustic noise by linear filtering methods. Thus suppression of acoustic noises and hindrances is possible at the expense of operated change of area of a cutting in the interval from 0 Hz to 300-1000 Hz, depending on a hindrance conditions.

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Кропотов, Юрий, Yuriy Kropotov, Алексей Белов, Aleksey Belov, Александр Проскуряков, and Aleksandr Proskuryakov. "EFFECTIVENESS INCREASE IN AUDIO EXCHANGE TELECOMMUNICATION SYSTEMS UNDER CONDITIONS OF EXTERNAL ACOUSTIC NOISE BY METHODS OF ADAPTIVE FILTERING." Bulletin of Bryansk state technical university 2019, no. 3 (March 27, 2019): 71–77. http://dx.doi.org/10.30987/article_5c8b5cebac6217.27543313.

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Signal processing in the telecommunication systems of audioinformation exchange is conditioned on the requirement in the separation of useful speech acoustic information, in the increase of the verification of information perception by subscribers of a communication system, in the stability increase of telecommunication systems at the suppression of external acoustic interference and echosignal compensations. Therefore during designing telecommunication systems, in particular, speakerphone systems (SS) operating under conditions of an active impact of external acoustic interference and echosignals, there is specified a problem of the algorithm formation of efficient noise suppression for an essential “signal-noise” ratio support. The investigation object is design methods of adaptive algorithms for speech signals processing and acoustic interference suppression at the expense of the controlled change of a rejection area in the range from 0 to 300…1000Hz depending on an interference situation. The work aim is an investigation of the speech signals characteristics and acoustic noise of different nature and also problems consideration in the matter of an algorithm creation for adaptive filtering and suppression of external acoustic interference and echosignals. At that the increase of the “signal-acoustic interference” ratio in the systems of audioexchange telecommunications is carried out through the methods of adaptive filtering. The results obtained in the course of the investigations of different acoustic interference suppression show that through the method of linear filtering in the system of telecommunications of speech information exchange it is possible to ensure the essential ratio Rs/Rak.pom. >20 dB and, accordingly, an essential syllab-ic legibility S ≥ 93%.

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Abbasova, T. S. "Development of rules in expert systems for the analysis and evaluation of telecommunications." Informacionno-technologicheskij vestnik 12, no. 2 (June 30, 2017): 47–63. http://dx.doi.org/10.21499/2409-1650-2017-2-47-63.

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Typical malfunctions that may occur in telecommunication systems due to the failure to meet the noise immunity requirements, as well as the characteristic features that can identify these problems, are analyzed. In the process of developing the knowledge base for the expert system for assessing the telecommunications infrastructure, the existing tools for developing knowledge bases have been improved.

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Lyakhovetsky, L. "Method of estimation of interference noise in transmission systems with orthogonal harmonic signals." Metrology and instruments, no. 3 (March 7, 2018): 17–20. http://dx.doi.org/10.33955/2307-2180(3)2018.17-20.

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The method of estimation of interference noise that arises in transmission systems with orthogonal harmonic signals due to linear distortions of signals in the telecommunication channel is proposed. The method can be used both for simulation of telecommunication systems, and for the construction of measuring devices with the function of estimation of interference noise based on the results of measuring the characteristics of the telecommunication channel.The results of estimation of interference noise for ADSL2 + subscriber access transmission system are presented.

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Kropotov, Yu A., A. A. Belov, A. A. Kolpakov, and A. Yu Proskuryakov. "The syllable intelligibility in the system of information transmission by speech signals depending on the intensity of acoustic noise." Information Technology and Nanotechnology, no. 2416 (2019): 277–82. http://dx.doi.org/10.18287/1613-0073-2019-2416-277-282.

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The paper investigates the effect of the signal-to-noise ratio on syllable intelligibility under the intense influence of external acoustic interference when exchanging voice messages in telecommunication systems of public address systems. The article discusses the effect on the syllable intelligibility of the signal / external acoustic noise ratio, examines the effect of the integral articulation index, the dependence of the perception coefficient of formants on the relative level of formant intensity, the dependence of the formant parameter on the geometric mean frequency of the i-th spectrum of the speech signal. In accordance with the results of studies of the integral articulation index depending on the signal-to-noise ratio, a function of syllable intelligibility depending on the signal-to-noise ratio was obtained, using which it is possible to determine the maximum value of the output signal-to-noise ratio in the audio exchange telecommunications system to obtain a given syllable intelligibility. At the same time, experimentally determined the value of the signal-to-noise ratio in the telecommunications system of audio exchange to obtain a syllable intelligibility of at least 93% for ensure full perception of the transmitted speech information.

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Abbasova, Tatiana Sergeevna, Natalya Petrovna Sidorova, Natalya Nikolaevna Teodorovich, and Elshan Maggeram Oglu Abbasov. "Evaluation of Telecommunications Electromagnetic Compatibility with the Use of Three-Dimensional Modeling Technology." Modern Applied Science 10, no. 10 (July 27, 2016): 224. http://dx.doi.org/10.5539/mas.v10n10p224.

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Three-dimensional modeling is used as a new way of presenting information about the electromagnetic compatibility of telecommunications infrastructure equipment. We analyzed the problem of modeling of electromagnetic noise waves equipment and communication channels of telecommunications monitoring systems. Conducted the analysis of control problems of telecommunications equipment electromagnetic compatibility. Described the real conditions of installing the electronic equipment in computational complexes. Using tools of 3D-modeling was formed cable route, taking into account the suppression of noise waves, placement of telecommunication devices and checking whether the threshold value of cable susceptibility for all options of its gasket between devices was transcended. It is proposed to study the behavior of electromagnetic fields in the cable lines with shielding cable, electrostatic discharge, providing set of measures for electromagnetic compatibility, to convert created in a three-dimensional environment model in a specialized settlement package. The prospects of the use 4D-, 5D-, 6D-simulation for analysis of the implementation of projects, reduction of operating and electromagnetic compatibility costs.

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Kholkina, Natalya. "INFORMATION TRANSFER EFFECTIVENESS OF WARNING AND TELECOMMUNICATION SYSTEMS OF AUDIO-EXCHANGE UNDER NOISE CONDITIONS." Bulletin of Bryansk state technical university 2020, no. 5 (May 13, 2020): 49–55. http://dx.doi.org/10.30987/1999-8775-2020-5-49-55.

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In the paper shown there is presented an approach to the solution of the problem of the effectiveness parameter assessment in telecommunication systems of operational and command communication, systems of warning speakerphone and audio-exchange. There are considered the matters of the dependence investigation of the acoustic speech signal/noise ratio to the assurance of the required syllabic legibility for the possibility to increase the function effectiveness of telecommunication systems and information exchange operated under complex noise situation. There is shown the dependence of formant legibility upon the meaning of average geometric frequencies in each i-th band of a frequency spectrum of acoustic speech signals. The degree of the impact upon syllabic legibility of the acoustic speech signal/noise ratio is shown. In the paper it is shown that for obtaining speech information with syllabic legibility higher than 93% required for complete perception by a subscriber it is necessary to ensure the acoustic signal/noise ratio at the level no less than 20 dB. The problems in the probability density approximation of acoustic signals with the use of generalized polynomials on function basis systems are presented.

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Semenko, Anatoliy, Nikolaj Kushnir, Natalia Bokla, and Yevhen Shestopal. "SYNTHESIS OF STRIP-BAND TELECOMMUNICATION SYSTEM WITH INCREASED CONFIDENTIALITY OF INFORMATION TRANSMISSION THROUGH USE OF PSSEVDOVIDOVYPOVY." Visnyk Universytetu “Ukraina”, no. 1 (28) 2020 (2020): 65–74. http://dx.doi.org/10.36994/2707-4110-2020-1-28-06.

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Currently, special attention is paid to the creation of broadband telecommunications systems with a noise-like signal. Such systems have indisputable advantages in noise immunity, in the confidentiality of information transmission, electromagnetic compatibility with neighboring electronic devices. The formation of a broadband signal in most cases is carried out by the method of direct spreading of the spectrum by manipulating the carrier frequency signal by a pulse pseudo-random sequence (PVP) –m-sequence, Gold, Kasami, Walsh sequence. Sequences such as a well-known attacker can pick up in the receiver and they can not be considered reliable protection of information. The use of the phenomenon of dynamic chaos provides an opportunity to find a new class of PVP, the structure of which is almost impossible to reproduce, so their use provides increased confidentiality of information transmission. PVP generators are built on the basis of one-dimensional chaotic mappings - logistic, quadratic and cubic, which are chaotic systems. When creating a PVP based on chaos, three secret encryption keys are used: for example, for logistic separation, this is the initial value, the equation parameter, and the start of the sequence. To increase the cryptosecurity of telecommunication systems, it is proposed to create PVP based on 2 chaotic signals (by logistic and quadratic mappings), which provides an increase in secret keys from three to six. The paper proposes a scheme for building a telecommunications system with high confidentiality of information transmission through the use of such PVP.

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Pliushch, Oleksandr, Viktor Vyshnivskyi, Volodymyr Tolubko, Vadym Mukhin, Serhii Ishcheryakov, Mykhailo Okhramovych, and Vitalii Loza. "Performance Study of Spread Spectrum Systems with Hard Limiters." International Journal of Computer Network and Information Security 12, no. 5 (October 8, 2020): 1–15. http://dx.doi.org/10.5815/ijcnis.2020.05.01.

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Use of spread spectrum systems in telecommunications is studied. It is shown that spread spectrum techniques can substantially enhance noise and interference immunity in the currently deployed information transmission networks. Primitive polynomials are proposed to obtain respective spreading codes. A spreading code consisting of 1023 chips is synthesized and its characteristics are studied. It is deduced that powerful interferences can exceed dynamic range of the receiving part of the system and, as a result, deteriorate information transmission. To overcome this problem, utilization of limiters is proposed, in which limitation level equals that of the internal noise of the receiving part. Computer simulation is employed to test the performance of the proposed solution. Performance of the spread spectrum system for information transfer is studied both without the limiter and with the limiter. Research results show that, for binary modulation, performance of the system with limitation and without limitation is nearly identical while limiters can substantially reduce requirements for the dynamic range. Compared to the existing approaches, it is proposed to use the synthesized spreading coding sequence with the limitation technique in practical implementations of those telecommunication networks, in which noise immunity and transmission concealment are required, such as in unmanned aerial vehicles. This can replace currently used approaches, such as frequency hopping, transmission power adjustment and antenna pattern changes.

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Matsenko, S., O. Borysenko, S. Spolitis, and V. Bobrovs. "Noise Immunity of the Fibonacci Counter with the Fractal Decoder Device for Telecommunication Systems." Latvian Journal of Physics and Technical Sciences 56, no. 5 (October 1, 2019): 12–21. http://dx.doi.org/10.2478/lpts-2019-0027.

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Abstract The paper presents the improved method of noise immune Fibonacci counting in the minimal form of representation. The method was tested and investigated in the developed noise immune pulse counter based on a minimal form of Fibonacci code with a fractal decoding device. The proposed device, which is simulated in the NI Multisim software, possesses a homogenous structure, increased noise immunity, performance and detection of bit errors in the process of its operation.

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Artyushenko, Vladimir Mikhailovich, and Tatyana Sergeevna Abbasova. "Increasing Noise Immunity of Electric Communication Channels in High-speed Telecommunication Systems." Biosciences Biotechnology Research Asia 11, Spl Edition Nov. 14 (April 30, 2014): 277–79. http://dx.doi.org/10.13005/bbra/1475.

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Shefer, О., B. Topikha, V. Shefer, and S. Myhal. "SYNTHESIS OF INVENTORIES TO THE INTERFERENCE OF INFORMATION AND TELECOMMUNICATION SYSTEMS." Системи управління, навігації та зв’язку. Збірник наукових праць 6, no. 58 (December 28, 2019): 115–22. http://dx.doi.org/10.26906/sunz.2019.6.115.

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The article deals with the development of analytical algorithms of information and telecommunication systems formation that are invariant to the obstacle (additiveornon-aditiveone). The basic approaches to determine the class of obstacles for which an invariant system can be constructed are discussed and analyzed in detail. It is established that the invariance property of a feedback system guarantees the given probability of receiving information, but it does not guarantee a preset speed of information transmission. Studies have shown that invariance is achieved by reducing the noise immunity of additive noise. In a second-order phase-difference modulation system, the error probability is invariant to the signal frequency, but it is greater than the error rate in the system with phase-difference modulation at a constant signal frequency. As a result of the conducted researches it is established that the maximum of the undetected error does not depend on the characteristics of the interference, but is determined solely by the parameters of the correction code. The ways of improving the qualitative characteristics of information and telecommunication systems to ensure their invariance to the obstacle have been determined by analytical means, which is confirmed by simulation results and experimental data

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Miller, S. E. "On the injection laser contribution to mode partition noise in fiber telecommunication systems." IEEE Journal of Quantum Electronics 25, no. 8 (1989): 1771–81. http://dx.doi.org/10.1109/3.34035.

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Miry, Mohammed, Ali Miry, and Hussain Khleaf. "Adaptive Noise Cancellation for speech Employing Fuzzy and Neural Network." Iraqi Journal for Electrical and Electronic Engineering 7, no. 2 (December 1, 2011): 94–101. http://dx.doi.org/10.37917/ijeee.7.2.2.

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Adaptive filtering constitutes one of the core technologies in digital signal processing and finds numerous application areas in science as well as in industry. Adaptive filtering techniques are used in a wide range of applications such as noise cancellation. Noise cancellation is a common occurrence in today telecommunication systems. The LMS algorithm which is one of the most efficient criteria for determining the values of the adaptive noise cancellation coefficients are very important in communication systems, but the LMS adaptive noise cancellation suffers response degrades and slow convergence rate under low Signal-to-Noise ratio (SNR) condition. This paper presents an adaptive noise canceller algorithm based fuzzy and neural network. The major advantage of the proposed system is its ease of implementation and fast convergence. The proposed algorithm is applied to noise canceling problem of long distance communication channel. The simulation results showed that the proposed model is effectiveness.

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Boiko, Juliy, Ilya Pyatin, Oleksander Eromenko, and Mykhailo Stepanov. "Method of the adaptive decoding of self-orthogonal codes in telecommunication." Indonesian Journal of Electrical Engineering and Computer Science 19, no. 3 (September 1, 2020): 1287. http://dx.doi.org/10.11591/ijeecs.v19.i3.pp1287-1296.

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The methodology description of the adaptive multi-threshold decoding of self-orthogonal codes in the telecommunication channels of information transfer is shown in this paper. The method of multi-threshold decoder modification is described on the basis of adaptive filtration algorithms. Principles of adaptive algorithms application provide for necessary data transmission validity in the case of the multi-threshold decoding are explored. The graphic charts of multi-threshold decoders noise immunity of self-orthogonal block and convolutional codes are presented. It is determined the coding gain (CG) for multi-threshold decoding schemes. The result of research conducted in the course of the paper is to develop a set of scientifically grounded theoretical positions and practical recommendations and proposals for the development of mechanisms of formalization of description of method of increasing of noise immunity of telecommunication systems transmitting information to the synthesis and improving receiver circuit modulated signals on the theory and practice the use of signal-code constructions (SCC) when deciding maximize system capacity information transmission in the presence of noise.

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Martín, Antonio J. López. "Web-Based Remote Learning of Communication Systems: A Successful Experience." International Journal of Electrical Engineering & Education 40, no. 3 (July 2003): 169–74. http://dx.doi.org/10.7227/ijeee.40.3.1.

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A web-based on-line framework has been created to augment an undergraduate course in communication theory aimed at Spanish telecommunication engineering students. Its aim is to enrich the students' understanding on basic topics such as analogue and digital communication systems, information theory, random signals and noise, as well as to provide remote support, additional information and interactive tools. As an ultimate goal, it tries to contribute to a redefinition of the role of the student as the principal actor of his or her own learning.

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Satar, Baris, Gokhan Soysal, Xue Jiang, Murat Efe, and Thiagalingam Kirubarajan. "Robust Weighted l1,2 Norm Filtering in Passive Radar Systems." Sensors 20, no. 11 (June 8, 2020): 3270. http://dx.doi.org/10.3390/s20113270.

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Conventional methods such as matched filtering, fractional lower order statistics cross ambiguity function, and recent methods such as compressed sensing and track-before-detect are used for target detection by passive radars. Target detection using these algorithms usually assumes that the background noise is Gaussian. However, non-Gaussian impulsive noise is inherent in real world radar problems. In this paper, a new optimization based algorithm that uses weighted l 1 and l 2 norms is proposed as an alternative to the existing algorithms whose performance degrades in the presence of impulsive noise. To determine the weights of these norms, the parameter that quantifies the impulsiveness level of the noise is estimated. In the proposed algorithm, the aim is to increase the target detection performance of a universal mobile telecommunication system (UMTS) based passive radars by facilitating higher resolution with better suppression of the sidelobes in both range and Doppler. The results obtained from both simulated data with α stable distribution, and real data recorded by a UMTS based passive radar platform are presented to demonstrate the superiority of the proposed algorithm. The results show that the proposed algorithm provides more robust and accurate detection performance for noise models with different impulsiveness levels compared to the conventional methods.

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Makri, R., M. Gargalakos, and N. K. Uzunoglu. "Design and Development of Monolithic Microwave Integrated Amplifiers and Coupling Circuits for Telecommunication Systems Applications." Active and Passive Electronic Components 25, no. 1 (2002): 1–22. http://dx.doi.org/10.1080/08827510211275.

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Recent advances in printed circuit and packaging technology of microwave and millimeter wave circuits result to the increasing use of MMICs in telecommunication systems. At Microwave and Fiber Optics Lab of NTUA several designs of various MMICs were conducted using the HP Eesof CAD Tool and FET and HEMT models of F20 and H40 GaAs foundry process of GEC Marconi. The designed MMICs are constructed in Europractice Organization while on-wafer probe measurements are performed in the Lab. In that framework, MMIC technologies are employed in the design of power and low noise amplifiers and couplers to be used for mobile and wireless communications as well as remote sensing and radar applications. A medium power linear FET amplifier has been designed with combining techniques on a single chip. The circuit operates at 14.4–15.2 GHz with an input power of−15dB m, a 36 dB total gain, while the input and output VSWR is less than 1.6. Due to high cost of MMIC fabrication only the first subunit was manufactured and tests verified the simulation results. Additionally, novel techniques have been used for the design of two coupling networks at 10 GHz in order to minimize the area occupied. A meander-kind design as well as shunt capacitors were implemented for a90°quadrature coupler and a Wilkinson one in order to reduce size. Finally, a two stages low noise amplifier was designed with the use of H40 GaAs process in order the differences between the relevant designs to be explored. The key specifications for this MMIC LNA include operation at 10 GHz with a total gain of 17 dB while the noise figure is less than 1.5 dB.

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Eng, Png Ching, Sun Song, and Bai Ping. "State-of-the-art photodetectors for optoelectronic integration at telecommunication wavelength." Nanophotonics 4, no. 3 (January 1, 2015): 277–302. http://dx.doi.org/10.1515/nanoph-2015-0012.

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AbstractPhotodetectors hold a critical position in optoelectronic integrated circuits, and they convert light into electricity. Over the past decades, high-performance photodetectors (PDs) have been aggressively pursued to enable high-speed, large-bandwidth, and low-noise communication applications. Various material systems have been explored and different structures designed to improve photodetection capability as well as compatibility with CMOS circuits. In this paper, we review state-of-theart photodetection technologies in the telecommunications spectrum based on different material systems, including traditional semiconductors such as InGaAs, Si, Ge and HgCdTe, as well as recently developed systems such as low-dimensional materials (e.g. graphene, carbon nanotube, etc.) and noble metal plasmons. The corresponding material properties, fundamental mechanisms, fabrication, theoretical modelling and performance of the typical PDs are presented, including the emerging directions and perspectives of the PDs for optoelectronic integration applications are discussed.

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Lucks, Marcio Barbosa, and Heuller A. C. Procópio. "Analysis of Companding Techniques Applied to Onboard Telemetry Systems." Applied Mechanics and Materials 232 (November 2012): 915–18. http://dx.doi.org/10.4028/www.scientific.net/amm.232.915.

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In order to increase the dynamic range and the signal-to-quantization noise ratio (SQNR) of telecommunication systems, companding techniques were developed, such as the μ-law and the A-law. These techniques allow a non-uniform quantization of the signal using a compressor circuit followed by a uniform quantizer in the transmitter and the reconstruction of the original signal on the receiver by means of an expander circuit. Some types of signals monitored during the flight of sounding vehicles and satellite launchers have a very wide dynamic range. In this paper, we propose and analyze the use of companding techniques in order to improve the SQNR of onboard telemetry systems.

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Borgosz, Jan, and Bogusław Cyganek. "Wavelet Based Method for an Analysis of Jitter in Telecommunication Signals." International Journal of Wavelets, Multiresolution and Information Processing 01, no. 03 (September 2003): 307–23. http://dx.doi.org/10.1142/s0219691303000207.

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This article describes a new method of the measure and analysis of the jitter phenomenon. Presented analysis is focused on the case of the telecommunication systems, but can be easily extended to other systems. This research is a continuation of the earlier work on the phase noise and jitter measurement systems. Method shown in this paper does not require generation of the reference clock in contrast to classic methods. It is rather based on the combination of the wavelet analysis and relational pattern recognition. This new approach to the jitter measurement problem gives very interesting results which are worth for further exploration. Authors give not only proposal but show measurement algorithm, which allows to estimate the jitter parameters by measure relation between the jitter wavelet base functions. In the background comparison of a classic and wavelet approaches to the jitter measurement problem is presented. In addition, such topics like the wavelet type, its order, as well as calibrating methods are also discussed.

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Gorbenko, I. D., А. А. Zamula, and V. L. Morozov. "INFORMATION SECURITY AND NOISE IMMUNITY OF TELECOMMUNICATION SYSTEMS UNDER CONDITIONS OF VARIOUS INTERNAL AND EXTERNAL IMPACTS." Telecommunications and Radio Engineering 76, no. 19 (2017): 1705–17. http://dx.doi.org/10.1615/telecomradeng.v76.i19.30.

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Kittisuwan, Pichid. "Image Denoising via Bayesian Estimation of Statistical Parameter Using Generalized Gamma Density Prior in Gaussian Noise Model." Fluctuation and Noise Letters 14, no. 02 (May 4, 2015): 1550017. http://dx.doi.org/10.1142/s0219477515500170.

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The application of image processing in industry has shown remarkable success over the last decade, for example, in security and telecommunication systems. The denoising of natural image corrupted by Gaussian noise is a classical problem in image processing. So, image denoising is an indispensable step during image processing. This paper is concerned with dual-tree complex wavelet-based image denoising using Bayesian techniques. One of the cruxes of the Bayesian image denoising algorithms is to estimate the statistical parameter of the image. Here, we employ maximum a posteriori (MAP) estimation to calculate local observed variance with generalized Gamma density prior for local observed variance and Laplacian or Gaussian distribution for noisy wavelet coefficients. Evidently, our selection of prior distribution is motivated by efficient and flexible properties of generalized Gamma density. The experimental results show that the proposed method yields good denoising results.

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Xiao, Y., and C. F. Mackenzie. "Remote Diagnosis in Dynamic Task Environments." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 40, no. 4 (October 1996): 218–22. http://dx.doi.org/10.1177/154193129604000416.

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Increasingly telecommunication systems have become an integral part of many professions. However, little empirical data and guidelines exist for designing telecommunication systems to facilitate decision makers in cooperative efforts in dynamic task environments. A preliminary experiment was conducted in which the subjects (all experienced in the domain concerned) were presented with video-tapes of previously recorded real-life trauma patient resuscitation. The experiment examined the subjects' ability to understand the status of the patient and resuscitation efforts shown in the video. The experiment was to simulate remote diagnosis tasks in which experts provide consultation through video linkage. The subjects were found to have a number of difficulties in achieving a full understanding. Hypotheses about the reasons that could explain these difficulties are proposed and they include (1) background noise, viewing range restriction, and insecure viewing access to remote sites (2) visual information overload due to the multiple action threads at remote sites (3) lack of adequate dynamic mental models of remote events and activities (4) lack of context information.

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Emagbetere, J. O., and P. A. Kuale. "Investigation of Harmonics in Power Generating Systems." Advanced Materials Research 18-19 (June 2007): 99–106. http://dx.doi.org/10.4028/www.scientific.net/amr.18-19.99.

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This paper investigates harmonics in power systems especially harmonics produced by synchronous generators as well as those by distributed generation systems, particularly these days when private generating systems are on the increase in Nigeria. For the work done so far, we found that some generators have near square waves, and these are characterized by their odd harmonics. An investigation of the harmonic emf waves conducted shows that these generators produces harmonic alternating mmf’s and fluxes. All harmonic fluxes produce emfs which are undesirable. The effect of these harmonics results in additional losses, vibration and noise, interferences, and very often stall motors. However the useful torque of a machine is usually produced by the fundamental flux wave which is a pure sine wave. The work is on-going. The waveforms are being analyzed so as to determine the full spectrum of the harmonics present in each case and subsequently investigate their effects in telecommunication systems including the present day GSM.

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Ikamas, Kęstutis, Dmytro B. But, Albert Cesiul, Cezary Kołaciński, Tautvydas Lisauskas, Wojciech Knap, and Alvydas Lisauskas. "All-Electronic Emitter-Detector Pairs for 250 GHz in Silicon." Sensors 21, no. 17 (August 28, 2021): 5795. http://dx.doi.org/10.3390/s21175795.

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The spread of practical terahertz (THz) systems dedicated to the telecommunication, pharmacy, civil security, or medical markets requires the use of mainstream semiconductor technologies, such as complementary metal-oxide-semiconductor (CMOS) lines. In this paper, we discuss the operation of a CMOS-based free space all-electronic system operating near 250 GHz, exhibiting signal-to-noise ratio (SNR) with 62 dB in the direct detection regime for one Hz equivalent noise bandwidth. It combines the state-of-the-art detector based on CMOS field-effect-transistors (FET) and a harmonic voltage-controlled oscillator (VCO). Three generations of the oscillator circuit are presented, and the performance characterization techniques and their improvement are explained in detail. The manuscript presents different emitter–detector pair operation modalities, including spectroscopy and imaging.

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Hasso, Alaaldin, and Karwan Jacksi. "Effects of Rounding and Truncating Methods of Quantization Error and SQNR for Sine Signal." Journal of Applied Science and Technology Trends 1, no. 1 (March 12, 2020): 08–12. http://dx.doi.org/10.38094/jastt113.

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Within the Analog to Digital Conversion (ADC), quantization noise is a duplicate of a Quantization Error (QE) which is introduced by quantization. In signal processing and telecommunication systems, the noise is non-linear and depends on the signal type. During the analog, Sine signal converts to the digital (ADC) process, the two methods are used Rounding and Truncating in-order to eliminate the error produced in the digitization process. The rounding method quantize assigns each sample of sine signal to the nearest quantization level. However, making the Truncating would have assigned each sample of sine signal to the quantization level below it. This paper compares the rounding and truncating methods of QE for sine signal, signal to quantization noise ratio, correlation coefficient, and regression equation of a line for both methods. Then, it calculates the residual sum of squares and compares it to the regression equations of the lines.

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Pradhan, Dipika D., and Abhilash Mandloi. "Performance Analysis of Flat Gain Wideband Raman Amplifier for S+C and C+L Band DWDM System." Advances in OptoElectronics 2018 (August 15, 2018): 1–7. http://dx.doi.org/10.1155/2018/5703805.

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Raman amplifier is an open area of research in telecommunication field. This paper discusses the performance of 64 channels of 10 Gbps WDM systems with backward multipump Raman amplifier. The main goal of this paper is the optimization of Raman amplifier to minimize its gain variation without using any gain flattening techniques. To increase the transmission capacity of DWDM system, Raman amplifier with backward multipump configuration is implemented. The optimized parameters such as pump power and frequencies are used to deliver both ground and excited state absorption for amplification in S+C and C+L band region. The pump power and frequencies are optimized through multitarget and multiparameter optimization tool available in OptiSystem software. Gain ripple was achieved <0.5 dB for this simulation setup. The maximum flat gain achieved is 8.6 dB and noise figure of <8 dB was achieved for this wide bandwidth without using gain flattening techniques. This amplifier design will be helpful for CATV applications and telecommunication networks.

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Rosenblum, Lawrence D., Jennifer A. Johnson, and Helena M. Saldaña. "Point-Light Facial Displays Enhance Comprehension of Speech in Noise." Journal of Speech, Language, and Hearing Research 39, no. 6 (December 1996): 1159–70. http://dx.doi.org/10.1044/jshr.3906.1159.

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Seeing a talker's face can improve the perception of speech in noise. There is little known about which characteristics of the face are useful for enhancing the degraded signal. In this study, a point-light technique was employed to help isolate the salient kinematic aspects of a visible articulating face. In this technique, fluorescent dots were arranged on the lips, teeth, tongue, cheeks, and jaw of an actor. The actor was videotaped speaking in the dark, so that when shown to observers, only the moving dots were seen. To test whether these reduced images could contribute to the perception of degraded speech, noise-embedded sentences were dubbed with the point-light images at various signal-to-noise ratios. It was found that these images could significantly improve comprehension for adults with normal hearing and that the images became more effective as participants gained experience with the stimuli. These results have implications for uncovering salient visual speech information as well as in the development of telecommunication systems for listeners who are hearing impaired.

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Samad, Md Abdus, Md Razu Ahmed, and Syed Zahidur Rashid. "An overview of rain attenuation research in Bangladesh." Indonesian Journal of Electrical Engineering and Computer Science 23, no. 2 (August 1, 2021): 902. http://dx.doi.org/10.11591/ijeecs.v23.i2.pp902-909.

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The demands of shifting to the operating frequency of wireless telecommunication systems at new higher frequency bands increase as day by day the necessity to transfer more data volume through wireless networks. Bangladesh has launched its first satel-lite, Bangabandhu-1, with 40 communication channels in the C and Ku frequency bands. Besides, a huge volume of terrestrial microwave backbone networks suffer from fading during rain across the country. Bangladesh experiences heavy rainfall in June-July-August. The rain has a remarkable impact on deteriorating the signal-to-noise ratio at the receiver end. To implement the 5G network, 2.6–60 GHz frequency bands are promising. However, the propagated waves in these bands are prone to fadedue to rain. Unfortunately, the rain attenuation model developed for other climatic conditions can not be used readily without customization. In this regard, to maintain quality telecommunication networks, proper rain attenuation model development is crucial. This work reviews rain attenuation research in Bangladesh, global research trends and the research scope to manage rain attenuation.

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Assaf, Mohammad Razk, and Abdel-Nasser Assimi. "Iterative Interference Cancellation for Coded Filter Bank Multicarrier Systems." International Journal of Embedded and Real-Time Communication Systems 10, no. 4 (October 2019): 81–93. http://dx.doi.org/10.4018/ijertcs.2019100105.

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Filter bank multicarrier is one of the candidates for future communication systems. Simple equalization methods cannot be directly applied due to the high interference from adjacent channels. In this article, the authors derive a soft-input/soft-output (SISO) equalizer based on the minimum mean square error (MMSE) criterion for the bit-interleaved coded system using a filter bank multi-carrier scheme with offset quadrature amplitude modulation (FBMC/OQAM). The authors use this SISO-MMSE equalizer in a turbo-equalization scheme for each sub-carrier. The difficulty in this implementation comes from the required processing delay per turbo-iteration due to the non-causal nature of the interference in this system. Therefore, the number of turbo-iterations is limited in order to limit the processing delay. The authors evaluate the performance of the proposed turbo-equalizer over the International Telecommunication Union (ITU) Vehicular B channel by mean of numerical simulations. The obtained results show the effectiveness of the proposed equalizer in term of signal-to-noise ratio (SNR) gain.

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Kropotov, Y. A., A. A. Belov, A. Y. Proskuryakov, and A. A. Kolpakov. "Investigation of signal models and methods for evaluating structures of processing telecommunication information exchange systems under acoustic noise conditions." Journal of Physics: Conference Series 1015 (May 2018): 022010. http://dx.doi.org/10.1088/1742-6596/1015/2/022010.

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M. El-Hageen, Hazem, Aadel M. Alatwi, and Ahmed Nabih Zaki Rashed. "Spatial optical transmitter based on on/off keying line coding modulation scheme for optimum performance of telecommunication systems." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 1 (January 1, 2021): 305. http://dx.doi.org/10.11591/ijeecs.v21.i1.pp305-312.

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This study has presented a spatial optical transmitter based on on off keying line coding modulation scheme for the optimum performance of telecommunication systems. The encircled flux versus fiber core radius, the 3D graph for fiber mode versus core radius, and the signal power level in dBm versus wavelength through coarse wavelength division multiplexing with a fiber length of 20 km are presented and discussed in detail. The total power measured in W and dBm as well as the signal power amplitude level obtained through the infinite impulse response (IIR) filter based on both Z domain and pole/zero coefficient filter types are illustrated clearly. Signal gain, noise figure, maximum Q factor, and received power are also clarified against bit rates for various modulation line coding schemes.

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Uryvsky, Leonid, Andriy Korniienko, and Bohdan Shmigel. "ANALYSIS OF TELECOMMUNICATION CHANNEL SPECTRAL CHARACTERISTICS WITH BLOCK CODING AT A CONSTANT SPEED OF THE MESSAGE SOURCE." Information and Telecommunication Sciences, no. 1 (June 29, 2021): 55–61. http://dx.doi.org/10.20535/2411-2976.12021.55-61.

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Background. The direction of development of modern electronic communication systems tends to increase the speed of information transmission. In turn, increasing the speed requires the use of additional resources of the communication channel and tools to maintain the specified reliability of the transmission under limited conditions. But resources are not free. That is why there is a need to establish a relationship between the conditions for reliable transmission in high-speed channels and the spectral and energy parameters of the information transmission system. Objective. The purpose of the paper is to analyse and describe the effect of block noise-tolerant coding on the rate of transmission of symbols in the communication channel while ensuring the required reliability of information transmission at a constant speed of the message source by increasing the frequency involved. Methods. The initial stage of the study is the presentation of system parameters in case of inaccurate transmission. Then a block redundant code is synthesized, which ensures the reliability of information transmission and the procedure of spreading the spectrum at a fixed speed of the message source is performed. Results. Recommendations on the method of selecting coding parameters in the procedure of spreading the spectrum and provided that the speed of the message source is constant are formed. Conclusions. Analysis of the possibilities of noise-tolerant coding at different energies of the communication channel under conditions of increasing the channel transmission rate at a fixed speed of the message source. Keywords: speed; message source; reliability; noise immunity.

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Hamidkhani, Mehdi, Rasool Sadeghi, and Mohamadreza Karimi. "Dual-Band High Q-Factor Complementary Split-Ring Resonators Using Substrate Integrated Waveguide Method and Their Applications." Journal of Electrical and Computer Engineering 2019 (September 9, 2019): 1–11. http://dx.doi.org/10.1155/2019/6287970.

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In modern microwave telecommunication systems, especially in low phase noise oscillators, there is a need for resonators with low insertion losses and high Q-factor. More specifically, it is of high interest to design resonators with high group delay. In this paper, three novel dual-band complementary split-ring resonators (CSRRs) featuring high group delay etched on the waveguide surface by using substrate integrated waveguides are investigated and proposed. They are designed for a frequency range of 4.5–5.5 GHz. Group delay rates for the first, second, and third resonators were approximated as much as 23 ns, 293 ns, and 90 ns, respectively. We also proposed a new practical method to develop a wide tuning range SIW CSRR cavity resonator with a small tuning voltage in the second resonator, which leads to about 19% and 1% of tuning frequency band in the first and second bands, respectively. Finally, some of their applications in the design of filter, diplexer, and low phase noise oscillator will be investigated.

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Daneshvar, Milad, Naser Parhizgar, and Homayoon Oraizi. "Design and implementation of the subsystem subject to emission of multicomponent high-frequency signals to ensure its reliability." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 5 (October 1, 2019): 4204. http://dx.doi.org/10.11591/ijece.v9i5.pp4204-4216.

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Telecommunication systems, especially digital ones, are mostly known to be immune to noise given their extensive range of applications. This study aimed to investigate the methods and tools used for the analysis of multicomponent signals input to high-frequency digital subsystems, including the analysis of changes in its electrical behavior. This research mainly focuses on analyzing a high-frequency telecommunication subsystem, recording the results, investigating the system behavior against signals with different amplitudes and phases, detecting the received signals, and measuring the phase differences. The study extended the mono-component signals to multi-component signals and accurately extracted the statistical signal specifications using analytic signals in the time-frequency domain. To this end, a method was proposed based on the switch matrix to relate the different components and parameters, and also a mathematical model based on the state-space equations was employed to evaluate the nonlinear system modes. Given that the decoupling of measurement parameters is a problem to be tackled from multiple aspects, the costs and test durations were also taken into calculations in addition to considering all the detection methods for interference signals, reliability and time under test.

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Moazzeni, Taleb, Henry Selvaraj, and Yingtao Jiang. "A Novel Multi-Exponential Function-based Companding Technique for Uniform Signal Compression over Channels with Limited Dynamic Range." International Journal of Electronics and Telecommunications 56, no. 2 (June 1, 2010): 125–28. http://dx.doi.org/10.2478/v10177-010-0016-1.

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A Novel Multi-Exponential Function-based Companding Technique for Uniform Signal Compression over Channels with Limited Dynamic Range Companding, as a variant of audio level compression, can help reduce the dynamic range of an audio signal. In analog (digital) systems, this can increase the signal-to-noise ratio (signal to quantization noise ratio) achieved during transmission. The μ-law algorithm that is primarily used in the digital telecommunication systems of North America and Japan, adapts a companding scheme that can expand small signals and compress large signals especially at the presence of high peak signals. In this paper, we present a novel multi-exponential companding function that can achieve more uniform compression on both large and small signals so that the relative signal strength over the time is preserved. That is, although larger signals may get considerably compressed, unlike μ-law algorithm, it is guaranteed that these signals after companding will definitely not be smaller than expanded signals that were originally small. Performance of the proposed algorithm is compared with μ-law using real audio signal, and results show that the proposed companding algorithm can achieve much smaller quantization errors with a modest increase in computation time.

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Kozel, V. M., D. A. Podvornaya, and K. A. Kovalev. "Peal factor of signals of 5G mobile service systems." Doklady BGUIR 18, no. 6 (October 1, 2020): 5–10. http://dx.doi.org/10.35596/1729-7648-2020-18-6-5-10.

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This article discusses the possible formats of signals of 5G mobile communication networks (NR, IMT-2020): configurations of the number of resource blocks and frequency shifts of subcarriers. modulation schemes, organizations of the physical level, as well as the broadband signals of these networks and, as a result, the need for introducing a margin on the linearity of the transceiver’s paths to eliminate distortion or the manifestation of blocking effects when the signal interferes with third-party means. We analyze the characteristics of the dynamic range of the signals from IMT-2020 ground mobile systems and make a conclusion about the noise-like signals. To find the ratio of the maximum amplitude to its average value and a given ratio not exceeded with a given probability, the Matlab mathematical models were used. We infer that the law of probability distribution of the module of the instantaneous amplitude of the 5G signals corresponds to the distribution characteristic of narrow-band radio noise. Based on the study, the peak factor of the signal of the IMT-2020 ground mobile systems for various variations is obtained and a sufficient level of power reserve is provided to ensure, with high probability, the transmission of the 5G signals through radio paths, eliminating signal distortion. The results of this study were applied in the examination of the electromagnetic compatibility of radio electronic devices of cellular mobile communications with existing and promising electronic means of civil and special purposes and in the study of the protection of ground satellite stations from the effects of radio electronic means of IMT-2020 cellular mobile telecommunication networks located at border territories.

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Sombrin, Jacques B. "Optimization criteria for power amplifiers." International Journal of Microwave and Wireless Technologies 3, no. 1 (February 2011): 35–45. http://dx.doi.org/10.1017/s1759078710000863.

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This paper describes existing and new criteria for comparison and optimization of non-linear power amplifiers such as RF or microwave transmitters. In addition to intermodulation, receiver noise, and losses in the transmission system, the proposed new criteria take into account efficiency or consumed power. This results in the global optimization of a combined signal-to-noise-plus-intermodulation ratio as a function of saturated or nominal power but also consumed or dissipated power. Saturated power is limited by available technology. Consumed power and dissipated power are some of the main constraints in telecommunication satellite payloads, mobile phone handsets, and RFID (Radio Frequency IDentification). Another constraint comes from the limited size of antennas, which limits the system equivalent isotropic radiated power and gain-to-temperature ratio. With the proposed criteria the designer will be able to compare different amplifier technologies and to optimize the design and operating point of each stage of a multistage amplifier or a linearizer for a given amplifier. Interference from same or other systems is also introduced in the optimization through the use of signal-to-noise-plus-IM-plus-interference ratio criteria.

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Muhammad, Fazal, Farman Ali, Usman Habib, Muhammad Usman, Imran Khan, and Sunghwan Kim. "Time Domain Equalization and Digital Back-Propagation Method-Based Receiver for Fiber Optic Communication Systems." International Journal of Optics 2020 (February 12, 2020): 1–13. http://dx.doi.org/10.1155/2020/3146374.

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Fiber optic communication systems (FOCSs) have attained a lot of attention by revolutionizing the telecommunication industry and offering new possibilities with the technical advancements in state-of-the-art high speed digital electronics. Advanced modulation formats make use of the phase, amplitude, and polarization of the optical signals at the same time to provide high spectral efficiency as compared with 1 bit/s/Hz for the intensity modulation direct detection system (IMDD), but are highly prone to transmission impairments. Thus, the effects that add up to the optical fiber impairments such as optical fiber chromatic dispersion (OFCD), polarization model dispersion (PMD), and phase offset and noise (POaN) need to be addressed at the receiver side. The development of components and algorithms to minimize these effects in next generation FOCSs with 100 Gbps data rate and beyond with long-haul transmission is still a challenging issue. In this paper, digital signal processing- (DSP-) assisted dispersion and nonlinear compensation techniques are presented to compensate for physical layer impairments including OFCD, PMD, and POaN. The simulations are performed considering Dual Polarization- (DP-) QPSK modulation format to achieve two-fold data rate to achieve spectral efficiency of 3.28 bits/s/Hz by making use of the polarization diversity and system performance is investigated in terms of bit error rate (BER), constellation diagrams, and quality factor (Q-factor) for different values of optical signal-to-noise ratio (OSNR), launch power (PL), and fiber length.

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Ермолаев, Валерий, Valeriy Ermolaev, Юрий Кропотов, and Yuriy Kropotov. "MODEL PARAMETER IDENTIFICATION OF ACOUSTIC SIGNALS IN AUDIO EXCHANGE TELECOMMUNICATION SYSTEMS UNDER CONDITIONS OF INTERFERENCE AND ACOUSTIC FEEDBACK SYSTEM." Bulletin of Bryansk state technical university 2019, no. 10 (November 7, 2019): 25–38. http://dx.doi.org/10.30987/article_5db95e85b8bb12.44709607.

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The paper reports the solution description for the problem of designing the models of the systems of information exchange with the acoustic feedback with the use of the methods of the linear functional-differential equation theory. With the aid of them it is ensured a stability increase in systems of operational-command loud-speaker communication and notice, and also the problem of echo decrease at the inputs of speech transforming devices is solved that conditions on quality increase of their functioning. In the paper there are presented models having a continuous consequence and taking into account a character of acoustic echo-signals in closed spaces more complete which results in authenticity increase of modeling results at echo-signal compensation. To solve the echo identification problem the functions of echo lag distribution are approximated by a number of exponents which simplifies the equations and allows accepting a consequence both at a finite and infinite interval. The investigation of the stability of models of systems with the acoustic feedback in the paper is carried out by a frequency method. At that there is considered an approach to the estimate of correlate and spectral functions of acoustic signals which is based on a parametric presentation of acoustic signals and components of noise constituents

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Sedunov, D. P., and A. S. Zhunusova. "Development of algorithm for receiving and decoding input signal using MTD decoder for subscriber terminals operating with low-orbit spacecraft." Omsk Scientific Bulletin, no. 175 (2021): 59–63. http://dx.doi.org/10.25206/1813-8225-2021-175-59-63.

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The relevance of the topic is determined by the need to increase the speed of data transmission in satellite telecommunication systems through the use of noise-proof coding. The speed of data transmission in a radio channel is actually determined by the level of interference present due to the fact that the radio transmission medium is a public environment and other electronic devices operate in it. The purpose of the article is to develop an algorithm for encoding and decoding the input signal using a multithreshold decoder (MTD) of rigid solutions for subscriber terminals operating with low-orbit spacecraft (NCA), and its comparison with a conventional PC decoder «Messi». The comparison allows us to conclude that the application of the developed algorithm is justified in systems where more stringent requirements are imposed on the probability of an error in the communication channel, while the «Messi» decoder is more appropriate to use in the presence of restrictions on computational complexity

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Zabala-Blanco, David, Marco Mora, Cesar A. Azurdia-Meza, and Ali Dehghan Firoozabadi. "Extreme Learning Machines to Combat Phase Noise in RoF-OFDM Schemes." Electronics 8, no. 9 (August 22, 2019): 921. http://dx.doi.org/10.3390/electronics8090921.

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Radio-over-fiber (RoF) orthogonal frequency division multiplexing (OFDM) systems have been revealed as the solution to support secure, cost-effective, and high-capacity wireless access for the future telecommunication systems. Unfortunately, the bandwidth-distance product in these schemes is mainly limited by phase noise that comes from the laser linewidth, as well as the chromatic fiber dispersion. On the other hand, the single-hidden layer feedforward neural network subject to the extreme learning machine (ELM) algorithm has been widely studied in regression and classification problems for different research fields, because of its good generalization performance and extremely fast learning speed. In this work, ELMs in the real and complex domains for direct-detection OFDM-based RoF schemes are proposed for the first time. These artificial neural networks are based on the use of pilot subcarriers as training samples and data subcarriers as testing samples, and consequently, their learning stages occur in real-time without decreasing the effective transmission rate. Regarding the feasible pilot-assisted equalization method, the effectiveness and simplicity of the ELM algorithm in the complex domain are highlighted by evaluation of a QPSK-OFDM signal over an additive white Gaussian noise channel at diverse laser linewidths and chromatic fiber dispersion effects and taking into account several OFDM symbol periods. Considering diverse relationships between the fiber transmission distance and the radio frequency (for practical design purposes) and the duration of a single OFDM symbol equal to 64 ns, the fully-complex ELM followed by the real ELM outperform the pilot-based correction channel in terms of the system performance tolerance against the signal-to-noise ratio and the laser linewidth.

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BENNANI, YOUNÈS, and FABRÌCE BOSSAERT. "MODULAR CONNECTIONIST MODELLING AND CLASSIFICATION APPROACHES FOR LOCAL DIAGNOSIS IN TELECOMMUNICATION TRAFFIC MANAGEMENT." International Journal of Computational Intelligence and Applications 01, no. 01 (March 2001): 53–70. http://dx.doi.org/10.1142/s146902680100007x.

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In Neural Networks (NN) applications, it is common practice to train several different networks and select the best one on the basis of performance on a validation set. There is a major disadvantage of such an approach: the network with the best performance on the validation set might not be the best one on new test data. In fact, the generalization performance on the validation set has a random component that is due to the data noise. An alternative approach to this problem is to use a combination of multiple NN classifiers. It is well known that such combinations can produce better performance than the best single network used in isolation. Several studies in different fields of the pattern recognition have experimentally shown that an appropriate combination of NN classifiers allows to capture complex phenomena, and to make decisions even with a great deal of information.3,11,12 The combination of multiple classifiers is a general problem in the pattern recognition area. Several methods for combining the outputs of multiple classifiers have been proposed: ensemble methods,14 boosting approaches,9 stacking techniques,27 multi-expert systems,2,16 and multi-modular architectures.3,13,18 A very rich synthesis of different methods of combining classifiers can be found in Ref. 28. An analytical framework to quantify the improvements in classification results that is due to combining classifiers is provided in Ref. 26. In this paper some contributions in combining multiple NN classifiers are presented. We give a combinational approach based on multi-modular systems for local diagnosis problem in the telephone network. In addition, we propose a combinational method for discrimination task using a fusion. The system validation will be performed on a disturbance identification problem.

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Supe, Andis, Kaspars Zakis, Lilita Gegere, Dmitrii Redka, Jurgis Porins, Sandis Spolitis, and Vjaceslavs Bobrovs. "Raman Assisted Fiber Optical Parametric Amplifier for S-Band Multichannel Transmission System." Fibers 9, no. 2 (February 1, 2021): 9. http://dx.doi.org/10.3390/fib9020009.

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In this paper we present results from the study of optical signal amplification using Raman assisted fiber optical parametric amplifier with considerable benefits for S-band telecommunication systems where the use of widely used erbium-doped fiber amplifier is limited. We have created detailed models and performed computer simulations of combined Raman and fiber optical parametric amplification in a 16-channel 40 Gbps/channel wavelength division multiplexed transmission system. Achieved gain bandwidth, as well as transmission system parameters—signal-to-noise ratio and bit-error-ratio—were analyzed by comparing the Raman assisted fiber optical parametric amplifier to the single pump fiber optical parametric amplifier. Results show that the 3 dB gain bandwidth in the case of combined amplification is up to 0.2 THz wider with 1.9 dB difference between the lowest and highest gain.

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Malykhina, Galina, Dmitry Tarkhov, Viacheslav Shkodyrev, and Tatiana Lazovskaya. "Intelligent LED Certification System in Mass Production." Sensors 21, no. 8 (April 20, 2021): 2891. http://dx.doi.org/10.3390/s21082891.

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It is impossible to effectively use light-emitting diodes (LEDs) in medicine and telecommunication systems without knowing their main characteristics, the most important of them being efficiency. Reliable measurement of LED efficiency holds particular significance for mass production automation. The method for measuring LED efficiency consists in comparing two cooling curves of the LED crystal obtained after exposure to short current pulses of positive and negative polarities. The measurement results are adversely affected by noise in the electrical measuring circuit. The widely used instrumental noise suppression filters, as well as classical digital infinite impulse response (IIR), finite impulse response (FIR) filters, and adaptive filters fail to yield satisfactory results. Unlike adaptive filters, blind methods do not require a special reference signal, which makes them more promising for removing noise and reconstructing the waveform when measuring the efficiency of LEDs. The article suggests a method for sequential blind signal extraction based on a cascading neural network. Statistical analysis of signal and noise values has revealed that the signal and the noise have different forms of the probability density function (PDF). Therefore, it is preferable to use high-order statistical moments characterizing the shape of the PDF for signal extraction. Generalized statistical moments were used as an objective function for optimization of neural network parameters, namely, generalized skewness and generalized kurtosis. The order of the generalized moments was chosen according to the criterion of the maximum Mahalanobis distance. The proposed method has made it possible to implement a multi-temporal comparison of the crystal cooling curves for measuring LED efficiency.

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Giansanti, Daniele, Andrea Giordano, and Sandra Morelli. "Validation of an automatic tool for the assessment of image quality in digital tele-echocardiography." Journal of Telemedicine and Telecare 14, no. 7 (October 2008): 342–44. http://dx.doi.org/10.1258/jtt.2008.007004.

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We investigated a novel tool for assessing image degradation in tele-echocardiography. Different video recordings from an echocardiographic examination were transmitted using commercial videoconferencing equipment via a local area network. Different compression schemes were selected, ranging from MPEG 1 to MPEG 4, with transmission at different bit rates ranging from 1.0 to 4.5 Mbit/s. Three methods were used to compare the transmitted and received video sequences: the peak signal to noise ratio, the Double Stimulus Impairment Scale (DSIS) and the National Telecommunication and Information Administration Virtual Quality Metric (VQM). The results showed that the most useful grading procedure was the subjective DSIS. There was a high correlation between the DSIS results and the VQM. The VQM could be thus an effective tool for evaluating tele-echocardiography transmission systems, avoiding the costs and times associated with conducting subjective tests in repeatable conditions.

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Науменко, Виктория Владимировна, Галина Анатольевна Проскура, Александр Владимирович Тоцкий, and Валерий Борисович Шаронов. "ИСПОЛЬЗОВАНИЕ РАЗВЕТВЛЕННОГО БИСПЕКТРАЛЬНО-ОРГАНИЗОВАННОГО КОДА В НЕСТАЦИОНАРНЫХ КАНАЛАХ СВЯЗИ С ЗАМИРАНИЯМИ." RADIOELECTRONIC AND COMPUTER SYSTEMS, no. 1 (March 23, 2019): 44–57. http://dx.doi.org/10.32620/reks.2019.1.05.

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One of the main problems in modern wireless telecommunication systems and networks is the transmission and reception of signals in a multipath environment. Due to the nonideal impulse response of the communication channel, the frequency selective fading of the transmitted signal occurs. Diffraction and interference effects create a complex non-stationary structure of the electromagnetic field, which varies greatly in space and time. The method of branched BIS is organized - redundant coding, which allows you to receive and recognize a signal in a digital communication system in the presence of additive Gaussian noise, multipath propagation of radio waves, fading, random signal delays, as well as random changes in Doppler frequency shift. The advantages of the bispectral signal processing method include the ability to identify and evaluate the phase relationships of the spectral components in the observation, high noise immunity with respect to additive Gaussian noise and invariance to random signal time delays. The proposed method is based on solving the problem of multi-alternative detection and distinguishing of known triple signals against the background of interference according to test statistics – estimating the amplitude bispectrum by comparing the corresponding peak values of bi-amplitudes at the output of the matched bispectral filter. Since the bi-amplitude serves as a measure of the contribution of the frequency-phase dependences specified in a polyharmonic signal, the reception rule is to choose a triplet as the solution of a bispectrically organized signal, whose frequency dependencies are most similar to the frequency dependencies in the adopted oscillation. The aim of the work is to substantiate the advantages of using a branched bispectrically-organized code in digital radio communication systems in conditions of fading and multipath propagation of radio waves in comparison with the known redundant code. The results of computer statistical modeling of communication systems with the proposed coding method and the known one show a lower probability of symbol error for branched bispectrically-organized redundant coding under conditions of multipath radio propagation channels within the considered Rice and Rayleigh fade models. Computer simulations performed to show that the proposed method of branched bispectrically-organized redundant coding improves noise immunity in the propagation of radio waves in a channel with additive white Gaussian noise and also in a multipath radio link with fast and slow fading compared to the known frequency-redundant system-prototype.

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Asif, Rameez, and William J. Buchanan. "Quantum-to-the-Home: Achieving Gbits/s Secure Key Rates via Commercial Off-the-Shelf Telecommunication Equipment." Security and Communication Networks 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/7616847.

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There is current significant interest in Fiber-to-the-Home (FTTH) networks, that is, end-to-end optical connectivity. Currently, it may be limited due to the presence of last-mile copper wire connections. However, in near future, it is envisaged that FTTH connections will exist, and a key offering would be the possibility of optical encryption that can best be implemented using Quantum Key Distribution (QKD). However, it is very important that the QKD infrastructure is compatible with the already existing networks for a smooth transition and integration with the classical data traffic. In this paper, we report the feasibility of using off-the-shelf telecommunication components to enable high performance Continuous Variable-Quantum Key Distribution (CV-QKD) systems that can yield secure key rates in the range of 100 Mbits/s under practical operating conditions. Multilevel phase modulated signals (m-PSK) are evaluated in terms of secure key rates and transmission distances. The traditional receiver is discussed, aided by the phase noise cancellation based digital signal processing module for detecting the complex quantum signals. Furthermore, we have discussed the compatibility of multiplexers and demultiplexers for wavelength division multiplexed Quantum-to-the-Home (QTTH) network and the impact of splitting ratio is analyzed. The results are thoroughly compared with the commercially available high-cost encryption modules.

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Mladenovic, Vladimir, and Danijela Milosevic. "A novel-iterative simulation method for performance analysis of non-coherent FSK/ASK systems over Rice/Rayleigh channels using the wolfram language." Serbian Journal of Electrical Engineering 13, no. 2 (2016): 157–74. http://dx.doi.org/10.2298/sjee151118002m.

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In this paper, a new approach in solving and analysing the performances of the digital telecommunication non-coherent FSK/ASK system in the presence of noise is derived, by using a computer algebra system. So far, most previous solutions cannot be obtained in closed form, which can be a problem for detailed analysis of complex communication systems. In this case, there is no insight into the influence of certain parameters on the performance of the system. The analysis, modelling and design can be time-consuming. One of the main reasons is that these solutions are obtained by utilising traditional numerical tools in the shape of closed-form expressions. Our results were obtained in closed-form solutions. They are resolved by the introduction of an iteration-based simulation method. The Wolfram language is used for describing applied symbolic tools, and SchematicSolver application package has been used for designing. In a new way, the probability density function and the impact of the newly introduced parameter of iteration are performed when errors are calculated. Analyses of the new method are applied to several scenarios: without fading, in the presence of Rayleigh fading, Rician fading, and in cases when the signals are correlated and uncorrelated.

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Journal articles on the topic 'Telecommunication systems – Noise'

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