Journal articles: 'Signal synthesi'

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Yoga, I. Putu Harta, and Gst Ayu Vida Mastrika Giri, S.Kom., M.Cs. "Virtual Hybrid Synthesizer Application." JELIKU (Jurnal Elektronik Ilmu Komputer Udayana) 8, no. 3 (January 27, 2020): 357. http://dx.doi.org/10.24843/jlk.2020.v08.i03.p19.

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Hybrid synthesizers can be syntheses with digital or analog signals on a hardware device. In this article hybrid means make a virtual digital synthesis which combines several synthesis methods. The method used is the synthesis method of additive, substractive, and amplitude modulation (AM). Where the initial signal is an oscillator by making waves with the form Sinusoide Wave, Square Wave and Saw Tooth Wave. This virtual synthesis produces sound that has the same fundamental frequency as the fundamental frequency of notes. Keywords: Hibrid Synthesizer, Additive, Substractive, Amplitude Modulation

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Zamula, A. A., I. D. Gorbenko, and Ho Tri Luc. "Statistical properties of derived signal systems." Radiotekhnika, no. 203 (December 23, 2020): 141–47. http://dx.doi.org/10.30837/rt.2020.4.203.14.

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The search for effective methods of synthesis of discrete signals (sequences) that correspond to the potentially possible limiting characteristics of correlation functions and possess the necessary correlation, structural, ensemble properties remains an urgent problem. The authors have proposed a method for the synthesis of derivatives of signal systems, for which orthogonal signals are used as the initial ones, and nonlinear discrete complex cryptographic signals (CS) are used as generating signals. The synthesis of the latter ones is based on the use of random (pseudo-random) processes, including algorithms for cryptographic information transformation. Derivative signals synthesized in this way have improved (in comparison with linear signal classes) ensemble and correlation properties, while the statistical properties of such signal systems remain unexplored. The paper presents the results of testing derived signal systems using the tests defined in FIPS PUB 140 and NIST 800-22. Analysis of the results obtained allows us to assert that the statistical properties of this class of derived signals satisfy the requirements for pseudo-random sequences: unpredictability, irreversibility, randomness, independence of symbols, etc. In essence, such signals do not differ from random sequences. The use of the proposed class of derived signals will improve the performance of signal reception noise immunity, information security and secrecy of the ICS functioning.

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Khrapov, S. D., and A. V. Strukova. "Synthesis of optimal transmitter signal, providing the maximum noise immunity of the equipment of aviation and space radio systems under the influence of a complex of noise." Informacionno-technologicheskij vestnik, no. 2 (July 30, 2019): 72–78. http://dx.doi.org/10.21499/2409-1650-2019-2-72-78.

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The questions related to the synthesis of the optimal signal of the transmitter providing the maximum mechanical stability of the equipment of aerospace radio systems under the influence of a complex of noise are considered and analyzed. The problem of finding the optimal signal for detection in non-Gaussian interference is considered. The criteria for the selection of signals and the conditions imposed on them are analyzed. Considered variational principles of synthesis signals. Examples of solving problems of synthesis of transmitted signals are given.

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Rogozinsky, G., M. Chesnokov, and A. Kutlyiarova. "Some New Mathematical Models of Synthesized Sound Signals." Proceedings of Telecommunication Universities 8, no. 2 (June 30, 2022): 76–81. http://dx.doi.org/10.31854/1813-324x-2022-8-2-76-81.

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Modern sound synthesis systems make it possible to implement various signal generation algorithms of higher complexity. The theory of sound synthesis actively uses the mathematical apparatus of analog and digital radio engineering and signal processing, however, it should be noted that the classical signal models used in acoustics are not adequate to real-world synthesized signals, mainly due to the significant complexity of the latter. This article presents some models of synthesized signals typical for practical use.

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Zhang, Xian Yi, Jian Xu, Xiang Quan Guo, Yan Ting Lan, and Jia Yan Tao. "A Signal Generator Based on AD9850." Advanced Materials Research 712-715 (June 2013): 1767–70. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.1767.

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This paper analyzes the advantages of the direct digital frequency synthesis (DDS) in signal generator applications, introduces the basic principles and characteristics of AD9850, a cost-effective chip, shows the overall scheme of a signal source design based on DDS and implements the hardware system. Experimental results show the signal generator can produce sine wave signals scoping from 100Hz to 5MHz, clock signals and triangular wave signals and can display frequency on the LCD.

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Kol'tso, N. E., S. A. Grenkov, and L. V. Fedotov. "Comparison of Radio Interferometers with Analog and Digital Extraction of Recorded Signal." Journal of the Russian Universities. Radioelectronics 23, no. 2 (April 28, 2020): 6–18. http://dx.doi.org/10.32603/1993-8985-2020-23-2-6-18.

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Introduction. Radio telescopes of Very Long Baseline Interferometry (VLBI) networks usually record several signals with relatively narrow (up to 32 MHz) bands, which are extracted by means of base band converters (BBC) from an analog noise signal of an intermediate frequency (IF) with bands up to 1 GHz. When processing data, frequency band synthesis is used. At new small radio telescopes (for example, RT-13), directly wideband IF signals are digitized. An ability to connect the RT-13 radio telescope to the “Quasar” VLBI complex and to international VLBI networks provides by a digital narrow-band signal extraction module developed in 2019.Aim. Determining the measuring accuracy of an interferometric group delay of a signal by a radio interferometer with a digital narrow-band signal extraction module and comparing the sensitivity of interferometers with analog and digital signal extraction systems.Materials and methods. Sensitivity losses of interferometers with different systems for detecting recorded signals were calculated. The accuracy of a multi-channel interferometer with the synthesis of a frequency band and of an interferometer with recording of digital broadband IF signals without band synthesis was compared. The results were confirmed by VLBI observations in the observatories of the “Quasar” complex.Results. When replacing the analog system of signal extraction with digital system the sensitivity losses of the interferometer were slightly reduced. The measurement accuracy of the interferometric group delay had not changed. Accuracy increased when digitally recording broadband IF signals and when synthesizing a frequency band significantly larger than the IF bandwidth. Conditions and minimum synthesized bands were determined under which the accuracy of the interferometer with the registration of narrowband signals can be higher than the accuracy of the interferometer with the registration of wideband IF signals.Conclusion. The problem of combining RT-13 radio telescopes with VLBI networks with recording of video frequency signals was solved. The efficiency of the installation of digital signal conversion systems at radio telescopes was shown.

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Dolinský, Pavol, Imrich Andráš, Linus Michaeli, and Domenico Grimaldi. "MODEL FOR GENERATING SIMPLE SYNTHETIC ECG SIGNALS." Acta Electrotechnica et Informatica 18, no. 3 (September 27, 2018): 3–8. http://dx.doi.org/10.15546/aeei-2018-0019.

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Plaksienko, V. S. "Linear-logical decision-making algorithm for signal processing." Vestnik of Don State Technical University 18, no. 4 (January 9, 2019): 385–91. http://dx.doi.org/10.23947/1992-5980-2018-18-4-385-391.

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Introduction. Heuristic synthesis is used to improve the efficiency of reception and processing of discrete signals under aprior information pressure. The analysis of the decisionmaking algorithm for the linear-logical processing of discrete signals in case of the incomplete aprior data on their parameters is presented. The work objective is to develop and analyze the efficiency of the linear-logical algorithms.Materials and Methods. New mathematical algorithms for the signal reception and processing, effective under conditions of a priori uncertainty, are proposed. They are based on the consideration of the structure of emissions and process exceedance in the signal processing channels.Research Results. Linear-logical algorithms for processing discrete signals are developed. They are based on the consideration of one, two and more detailed characteristics of emissions or exceedance of random processes.Discussion and Conclusion. The results obtained can be useful in the synthesis of algorithms and devices for the signal reception and processing. Algorithms and devices are implemented both in an analog form and in the form of algorithms for computers. The simulation programs for the signal processing under conditions of the considerable uncertainty of aprior information on the signals and the channels of their distribution are developed.

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Gorbenko, Ivan, and Oleksandr Zamula. "Devising methods to synthesize discrete complex signals with required properties for application in modern information and communication systems." Eastern-European Journal of Enterprise Technologies 3, no. 9(111) (June 30, 2021): 16–26. http://dx.doi.org/10.15587/1729-4061.2021.234674.

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Information and communication systems (ICSs) must comply with increasingly stringent requirements to ensure the reliability and speed of information transmission, noise immunity, information security. This paper reports the methods to synthesize discrete complex cryptographic signals, underlying the construction of which are random (pseudo-random) processes; the methods for synthesizing characteristic discrete complex signals whose construction is based on using the nature of the multiplicative group of a finite field; the results of studying the properties of the specified signal systems. It is shown that the methods built provide a higher synthesis performance than known methods and make it possible to algorithmize the synthesis processes for the construction of software and hardware devices to form such signals. The win in the time when synthesizing nonlinear signals in finite fields using the devised method is, compared to the known method, for the period of 9,972 elements is 1,039.6 times. The proposed method for synthesizing the entire system of such signals, based on decimation operation, outperforms the known method of difference sets in performance. Thus, for a signal period of 2,380 elements, the win in time exceeds 28 times. It has also been shown that the application of such systems of complex signals could improve the efficiency indicators of modern ICSs. Thus, the imitation resistance of the system, when using complex discrete cryptographic signals with a signal period of 1,023 elements, is four orders of magnitude higher than when applying the linear signal classes (for example, M-sequences). For a signal period of 1,023 elements, the win (in terms of structural secrecy) when using the signal systems reported in this work exceeds 300 times at a period of 8,192, compared to the signals of the linear form (M-sequences)

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Zamula, Alexander, and Ivan Gorbenko. "Optimization for the quick-code methods for the synthesis of discrete signals – physical carriers of data in information-communication systems." Physico-mathematical modelling and informational technologies, no. 32 (July 8, 2021): 126–30. http://dx.doi.org/10.15407/fmmit2021.32.126.

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The paper presents the theoretical foundations of synthesis and analysis of complex nonlinear discrete cryptographic signals, the basis for the synthesis of which are random (pseudo-random) processes, including algorithms for cryptographic transformation of information, as well as methods for optimizing the synthesis of these signals using decimation and discrete programming. namely, the method of branches and boundaries. In order to improve the performance of signal generation and processing, estimates of the effectiveness of the decimation procedure are proposed and presented. It is shown that the use of the studied signal systems will improve the efficiency of modern ICS (speed of data generation and processing devices, noise immunity, information security, secrecy, protection against input (imposition) of false messages, message falsification, data integrity, etc.).

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Farrow, John M., and Everett C. Pesci. "Two Distinct Pathways Supply Anthranilate as a Precursor of the Pseudomonas Quinolone Signal." Journal of Bacteriology 189, no. 9 (March 2, 2007): 3425–33. http://dx.doi.org/10.1128/jb.00209-07.

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ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that causes serious infections in immunocompromised patients and those with cystic fibrosis (CF). This gram-negative bacterium uses multiple cell-to-cell signals to control numerous cellular functions and virulence. One of these signals is 2-heptyl-3-hydroxy-4-quinolone, which is referred to as the Pseudomonas quinolone signal (PQS). This signal functions as a coinducer for a transcriptional regulator (PqsR) to positively control multiple virulence genes and its own synthesis. PQS production is required for virulence in multiple models of infection, and it has been shown to be produced in the lungs of CF patients infected by P. aeruginosa. One of the precursor compounds from which PQS is synthesized is the metabolite anthranilate. This compound can be derived from the conversion of chorismate to anthranilate by an anthranilate synthase or through the degradation of tryptophan via the anthranilate branch of the kynurenine pathway. In this study, we present data which help to define the kynurenine pathway in P. aeruginosa and show that the kynurenine pathway serves as a critical source of anthranilate for PQS synthesis. We also show that the kyn pathway genes are induced during growth with tryptophan and that they are autoregulated by kynurenine. This study provides solid foundations for the understanding of how P. aeruginosa produces the anthranilate that serves as a precursor to PQS and other 4-quinolones.

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Yang, Yuxiang, He Bian, Fangling Du, Qiang Sun, and He Wen. "Development of a Stair-Step Multifrequency Synchronized Excitation Signal for Fast Bioimpedance Spectroscopy." BioMed Research International 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/143461.

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Wideband excitation signal with finite prominent harmonic components is desirable for fast bioimpedance spectroscopy (BIS) measurements. This work introduces a simple method to synthesize and realize a type of periodical stair-step multifrequency synchronized (MFS) signal. The Fourier series analysis shows that thep-order MFS signalf(p,t)has constant 81.06% energy distributed equally on itsp 2nth primary harmonics. The synthesis principle is described firstly and then two examples of the 4-order and 5-order MFS signals,f(4,t)andf(5,t), are synthesized. The method to implement the MFS waveform based on a field-programmable gate array (FPGA) and a digital to analog converter (DAC) is also presented. Both the number and the frequencies of the expected primary harmonics can be adjusted as needed. An impedance measurement experiment on a RC three-element equivalent model is performed, and results show acceptable precision, which validates the feasibility of the MFS excitation.

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Korchynskyi, V. V., V. I. Kildishev, A. M. Berdnikov, and K. O. Smazhenko. "INCREASE OF STEALTH TRANSMISSION BASED ON TIMER SIGNALS AND LINEAR FREQUENCY MODULATION." Proceedings of the O.S. Popov ОNAT 1, no. 1 (August 27, 2020): 53–58. http://dx.doi.org/10.33243/2518-7139-2020-1-1-53-58.

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Recently, much attention has been paid to the research of the properties and methods of forming complex noise-like signals to increase the noise immunity of radio communication systems operating in the conditions of electronic conflict. Using such signals, the tasks are resolved to improve the noise immunity and the main indicators of transmission stealth (energy, structural and information). For the task of the synthesis noise-like signals using timer signal designs in combination with the method of spreading the spectrum based on linear frequency modulation is proposed. The advisability of using timer signals is justified by their properties, which increase the noise immunity and stealth transmission. In contrast to positional codes, timer signals have more complex structure for construct signal construction. The initial parameters for constructing timer signals allow the formation of various sets of signal constructions. Such variational possibilities of constructing timer signals substantially increase the potential structural stealth of the transmission. Also based on timer signals, noise immunity coding is implemented without additional test elements. In the article A method for synthesizing noise-like signals based on linear frequency modulation and timer signal designs is proposed.

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DeKruyff, R. H., T. Turner, J. S. Abrams, M. A. Palladino, and D. T. Umetsu. "Induction of human IgE synthesis by CD4+ T cell clones. Requirement for interleukin 4 and low molecular weight B cell growth factor." Journal of Experimental Medicine 170, no. 5 (November 1, 1989): 1477–93. http://dx.doi.org/10.1084/jem.170.5.1477.

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We have analyzed in detail the precise requirements for the induction of human IgE synthesis using several experimental approaches with purified B cells and well-characterized alloantigen-specific CD4+ T cell clones expressing different profiles of lymphokine secretion. Using these clones under cognate conditions in which the B cells expressed alloantigens recognized by the cloned T cells, we have confirmed that IL-4 is required for the induction of IgE synthesis, but we have clearly demonstrated that IL-4 by itself is not sufficient. With several cloned CD4+ T cell lines, including an IL-4-producing clone that could not induce IgE synthesis, and cloned T cells pretreated with cyclosporin A to inhibit lymphokine synthesis, we showed that Th cell-B cell interactions are necessary for IgE synthesis, and that low molecular weight B cell growth factor (LMW-BCGF) and IL-4, in combination, are lymphokines of major importance in the induction of IgE synthesis. Together our results indicate that optimal induction of an IgE-specific response requires the exposure of B cells to a particular complex of signals that include (a) a signal(s) involving Th-B cell interaction that primes B cells to receive additional signals from soluble lymphokines, (b) a specific B cell proliferative signal provided by LMW-BCGF, and (c) a specific B cell differentiation signal provided by IL-4.

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Chen, Zhang Mei. "Research on Blind Estimation and Synthesis of FM Speech Frequency Hopping Signal." Scholars Journal of Engineering and Technology 9, no. 9 (October 28, 2021): 152–54. http://dx.doi.org/10.36347/sjet.2021.v09i09.005.

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This paper mainly studies the blind estimation and synthesis of frequency hopping points of speech signals based on frequency modulation in the case of frequency hopping.FM voice frequency hopping signal transmitter and receiver are built based on MATLAB platform. The transmitter FM modulates the original signal and then performs frequency hopping processing; the receiver blind estimates the frequency hopping point of the received signal.

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Zheleznjak, V. K., S. V. Lavrov, A. G. Filipovich, and M. M. Baranouski. "Synthesis of a measuring composite signal for assessing the security of speech signals during discrete-quantized transformation." Doklady BGUIR 18, no. 6 (October 1, 2020): 81–87. http://dx.doi.org/10.35596/1729-7648-2020-18-6-81-87.

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The purpose of the work is to systematically analyze and generalize a high-precision measuring signal for assessing the security in leakage channels in high-level noise by discrete-quantized representation of speech signals using the principles of amplitude-pulse modulation. It has been established that time sampling and level quantization of high-speed high-quality speech signals for digitalization are the main sources of information leakage. It is shown that to determine the degree of information security for high-quality high-speed transmission in broadband information transmission channels, it is necessary to use a complex measuring (test) composite signal. Requirements for the measuring signal are determined by the features of the discretequantized representation of speech signals. It is proposed to use a periodic pulse sequence of a triangular shape as a measuring signal. The triangular measurement signal has an advantage over the harmonic signal in the quantization noise extraction process, since allows you to achieve higher accuracy when processing it. To assess the security of the channel due to pulse-amplitude modulation, a harmonic signal is used, formed from a periodic pulse sequence of a triangular shape by the Fourier transform method. The use of the proposed measuring composite signal makes it possible to establish its numerical dependence with the numerical value of the signal taken as normalized and compare it to make a decision about the security of the speech signal. The materials presented in the article are original and can be used to assess the security of the channels of leakage of speech signals converted into digital form. In addition, the results obtained make it possible to carry out further studies of the security of speech signals during their reverse conversion from digital form to the original signal.

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Bedzhev, Borislav. "Method for synthesis of large families of signals with low correlation." Journal scientific and applied research 2, no. 1 (December 3, 2012): 13–20. http://dx.doi.org/10.46687/jsar.v2i1.37.

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In the paper a new method for synthesis of large families of signals with low auto- and crosscorrelation is presented. It is based on the known method for generation of Gold sets but is not related to a certain value of the decimation coefficient d. As a result it allows generating of families, consisting of p-ary M –sequences, for arbitrary values of p and the degree of their characteristic equation.

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Gorbenko, I. D., A. A. Zamula, and Ho Tri Luc. "Methods of synthesis and formation of a system of nonlinear discrete signals for modern information and communication systems." Radiotekhnika, no. 203 (December 23, 2020): 126–32. http://dx.doi.org/10.30837/rt.2020.4.203.12.

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The paper presents the results of solving the urgent problem of improving the performance indicators of information and communication systems (ICS), in particular, information security, noise immunity, secrecy, the speed of formation and processing of information. The use of the distributed spectrum technology (broadband noise-like signals) is a promising direction for ensuring the security of information resources. The methods used for data formation and processing, as well as the classes of broadband signals used as physical data carriers, do not allow providing the necessary (especially for critical infrastructure facilities) indicators of information security and noise immunity. In this case, as discrete sequences (DS) that expand the spectrum (manipulate the carrier frequency), should be used DS based on nonlinear construction rules and having improved correlation, ensemble and structural properties. Methods for the synthesis and formation of nonlinear discrete complex signals, namely, the so-called cryptographic signals, are proposed. The first method, presented in the article, uses random (pseudo-random) processes. Another method is based on the implementation of the operation of decimation of the original discrete sequence of symbols obtained from the results of the implementation of the first method; it provides the synthesis of an ensemble of signals for a certain signal duration. Analytical expressions are obtained for determining the synthesis time of an ensemble of signals using the proposed methods. It is shown that the speed of the signal generation method based on the decimation operation for a certain signal duration is more than three orders of magnitude higher than the speed of the method based on the random (pseudo-random) processes used. At the same time, based on the carried out computer simulation, it is shown that the signals obtained using the proposed methods have identical correlation, ensemble, and structural properties.

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Gorbenko, I. D., and A. A. Zamula. "Theoretical approaches to the synthesis of discrete signals with necessary properties." Radiotekhnika, no. 206 (September 24, 2021): 25–32. http://dx.doi.org/10.30837/rt.2021.3.206.02.

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Methods for information exchange, formation and processing of data used in information and communication systems (ICS), as well as classes of broadband signals used as a physical data carrier, do not provide the necessary (for individual ICS applications) indicators of cyber and information security, noise immunity of reception signals and secrecy of IKS functioning. Most of the existing systems use signals, the construction of which is based on linear laws, which allows an attacker, based on the establishment of the parameters of the signals used in the system, to carry out deliberate interference in the operation of the ICS with minimal energy consumption. The article presents conceptual approaches to the construction of secure ICS, which determine the need to cover the entire spectrum of information transformations in the complex, and based on the synthesis of signal systems with improved ensemble, correlation, structural properties. A method is proposed for synthesizing discrete derivatives of signals based on nonlinear discrete complex cryptographic signals (CS) and orthogonal signals formed on the basis of the rows of the Hadamard matrix (initial signals),. Based on computer modeling and the performed calculations, it is shown that the derivative signals formed on the basis of cryptographic sequences and rows of the Hadamard matrix have improved properties compared to orthogonal and linear classes of signals. Approaches to the construction are stated and a general characteristic of the hardware-software complex for synthesis, analysis, study of properties, generation, processing of a number of studied signal classes is given. It is shown that the use of such signals will improve such indicators of the system functioning as information security, noise immunity of signal reception and secrecy of functioning.

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Gorbenko, I. D., O. V. Potii, and A. A. Zamula. "The concept of synthesis of one class of self-synchronizing discrete signals." Radiotekhnika, no. 204 (April 9, 2021): 24–29. http://dx.doi.org/10.30837/rt.2021.1.204.03.

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The use of broadband signals (BSS) makes it possible to increase the noise immunity of information and communication systems (ICS) when exposed to structural (mutual) and organized interference. The real noise immunity will be lower than the potential one. The reason for the decrease in noise immunity, when entering synchronism and when distinguishing signals, is the presence of side peaks of the correlation functions. Proceeding from this, the NLS used in ICS should have such correlation properties when the side peaks of the NLS CF are as small as possible, i.e. ideally should tend to zero. In this case, it is necessary to determine the influence of side peaks on the characteristics of signal detection, measure their parameters, distinguish signals, and find the conditions for obtaining small side peaks. The problem of synthesizing a class of signals with given correlation, ensemble and structural properties, as well as properties of "blurring" in correlation characteristics, is formulated and solved in general form. The specified property ("fuzziness") means that increasing or decreasing the length of the discrete signal does not change the correlation properties of the discrete sequence on the basis of which the signal is synthesized. The use of many of these signal systems in modern information and communication systems will improve the performance indicators of such systems, first of all, noise immunity, secrecy, information security, noise immunity of signal reception.

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Yerokhin, Viktor, and Oleksandr Vakulenko. "Evolutoin of algorithms for separation of optimal two mutually unorthogonal signals of binary phase modulation." Collection "Information Technology and Security" 10, no. 1 (June 30, 2022): 83–97. http://dx.doi.org/10.20535/2411-1031.2022.10.1.261178.

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A review of the results of the development of the methodology for the synthesis of the separation-demodulation algorithms of two mutually non-orthogonal binary phase modulation signals in the length of the information clock interval, synchronous and asynchronous according to the clock points, with continuous and intermittent radiation. The evolution of algorithms for optimal separation of two mutually non-orthogonal signals of binary phase modulation has the following sequence: signals are mutually synchronous by clock points (communication channel – with constant parameters, non-seeding oscillations are represented by functions integrated with the square; the signals are mutually synchronous in clock points, the second interfering signal is intermittent; signals are mutually asynchronous in clock points; the signals are mutually asynchronous in clock points, the second interfering signal is intermittent; signals are mutually synchronous in clock points, both signals are discontinuous. At the same time, the minimum probability of an error in the estimation of the discrete information parameter of the first (useful) signal was assumed as the optimality criterion. The results of a comparative review of algorithms for the separation of two mutually non-orthogonal binary FM signals demonstrate their evolutionary nature. The identified main regularities make it possible to obtain descriptions of signal separation procedures with mismatched clock frequencies without performing intermediate signal processing procedures. The gradual process of complicating synthesis tasks led to the discovery of gradual regularities in the structures of the separation-demodulation algorithms of two binary FM signals, which provides an opportunity to formulate directions for further research, which should be based on the provisions of the theory of multi-user detection. Namely, the revealed regularities are the basis for conducting further research in order to solve similar problems with the gradual further complication of the initial conditions. Priority consideration in the future will be given to tasks that have theoretical interest and practical value: when both signals are characterized by non-stationary intermittent emission modes and are asynchronous in clock points; when they are characterized by packet transmission mode; when band-efficient types of modulation are used (MSK, GMSK – first of all).

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Butyrskiy, Evgeniy, and Vitaliy Rahuba. "Polyharmonic signals and their properties." National Security and Strategic Planning 2020, no. 3 (September 30, 2020): 37–50. http://dx.doi.org/10.37468/2307-1400-2020-3-37-50.

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This article proposes a new approach to signal synthesis to ensure the stealth and safety of active location tools, which improves the efficiency of lighting. The work has been classified complex broadband signals, considered the class of polyharmonic and band signals, their pros and cons, the prospects of application in the systems of location, shows the relationship of their signals with hyperbolic function and generalized range Fibonacci.

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Volosyuk, Valeriy, Volodymyr Pavlikov, Simeon Zhyla, Eduard Tserne, Oleksii Odokiienko, Andrii Humennyi, Anatoliy Popov, and Oleh Uruskiy. "Signal Processing Algorithm for Monopulse Noise Noncoherent Wideband Helicopter Altitude Radar." Computation 10, no. 9 (August 31, 2022): 150. http://dx.doi.org/10.3390/computation10090150.

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Radio altimeters are an important component of modern helicopter on-board systems. These devices currently involve the use of narrowband deterministic signals, that limits their potential technical characteristics. Given the significant breakthrough in the development of wideband and ultra-wideband radio electronics, it is promising to create on-board radio complexes capable of obtaining the necessary information using wideband stochastic signals. At the same time, when developing such complexes, it is important to use optimal synthesis methods for radio systems, which will allow optimal signal processing algorithms and potential accuracy parameters to be obtained. In this work, the algorithm to measure flight altitude for a helicopter or an unmanned aerial vehicle based on the processing of wideband and ultra-wideband pulsed stochastic signals is synthesized for the first time by the maximum-likelihood method. When formulating the problem, the mathematical model of the signal and observation is specified, and their statistical characteristics are investigated. The peculiarity of the synthesis task is the use of a noise pulse transmitter, which implements the function of an underlying surface illuminator, as well as considering the signal structure destruction during its radiation, propagation, and reflection. This signal shape destruction makes it impossible to synthesize a radar with internally coherent processing when working on one receiving antenna. In accordance with the synthesized algorithm, a simulation model of a pulsed radar with a stochastic probing signal has been developed and the results of its modeling are presented.

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WEN, YUMEI, PING LI, JIN YANG, and ZHANGMIN ZHOU. "ADAPTIVE LEAK DETECTION AND LOCATION IN UNDERGROUND BURIED PIPELINES." International Journal of Information Acquisition 01, no. 03 (September 2004): 269–77. http://dx.doi.org/10.1142/s0219878904000240.

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The vibrational acoustic signals collected on pipelines contain substantial information concerning the working status of pipelines. They can be used for pinpointing leaks in buried pipelines. However, because of the complexity of signal composition and the heavy corruption of signals by ambient noises, it is essential to set up an appropriate signal model and scheme of analysis and synthesis in order to extract leak signatures and specify leak locations. In addition, the features of vibrational acoustic signals vary with materials, sizes and buried conditions of tubular pipes. It is difficult to pre-determine the knowledge of signals, such as the spectral knowledge. Here, an adaptive detection and estimation strategy is proposed based on LMS adaptive filtering and modified Wavelet denoising. The feasibility leak detection and location estimation is first automatically analysed by the signal processing procedure without any prerequisite on signals and then the procedure adaptively finds better estimate. With the proposed schemes, even where collected signals are heavily blurred by bursting interferences and present non-stationary, the instrument may also carry on detection and achieve effective results.

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Rus, Guillermo, Shi-Chang Wooh, and Rafael Gallego. "Processing of Ultrasonic Array Signals for Characterizing Defects. Part I: Signal Synthesis." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 54, no. 10 (October 2007): 2129–38. http://dx.doi.org/10.1109/tuffc.2007.508.

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Sun, Zhongbo, Jiajia Jiang, Yao Li, Chunyue Li, Zhuochen Li, Xiao Fu, and Fajie Duan. "An automated piecewise synthesis method for cetacean tonal sounds based on time-frequency spectrogram." Journal of the Acoustical Society of America 151, no. 6 (June 2022): 3758–69. http://dx.doi.org/10.1121/10.0011551.

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Bionic signal waveform design plays an important role in biological research, as well as bionic underwater acoustic detection and communication. Most conventional methods cannot construct high-similarity bionic waveforms to match complex cetacean sounds or easily modify the time-frequency structure of the synthesized bionic signals. In our previous work, we proposed a synthesis and modification method for cetacean tonal sounds, but it requires a lot of manpower to construct each bionic signal segment to match the tonal sound contour. To solve these problems, an automated piecewise synthesis method is proposed. First, based on the time-frequency spectrogram of each tonal sound, the fundamental contour and each harmonic contour of the tonal sound is automatically recognized and extracted. Then, based on the extracted contours, four sub power frequency modulation bionic signal models are combined to match cetacean sound contours. Finally, combining the envelopes of the fundamental frequency and each harmonic, the synthesized bionic signal is obtained. Experimental results show that the Pearson correlation coefficient (PCC) between all true cetacean sounds and their corresponding bionic signals are higher than 0.95, demonstrating that the proposed method can automatically imitate all kinds of simple and complex cetacean tonal sounds with high similarity.

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Rassomakhin, S. G., A. A. Zamula, I. D. Gorbenko, and Ho Tri Luc. "Comparative analysis of noise immunity of reception of nonlinear complex discrete signals with standard signals AFM-16 BPSK." Radiotekhnika, no. 203 (December 23, 2020): 133–40. http://dx.doi.org/10.30837/rt.2020.4.203.13.

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The article shows that the solution to the problem of increasing the noise immunity (noise immunity and secrecy of functioning) of the ICS can be achieved using systems of nonlinear signals with improved ensemble, structural and correlation properties. Two classes of nonlinear complex discrete signals are considered: characteristic discrete signals (CDS) and cryptographic signals (CS). Methods for the synthesis of these signals are presented. The paper gives a statistical simulation model for studying the noise immunity of various classes of signals in the Gaussian channel. Using this model, estimates of the dependence of the error probability on the signal-to-noise ratio were obtained for various classes of signals, namely: CDS, KS and standard BPSK AFM-16 signals. It is shown that for the signal-to-noise ratio – 10 the error probability for the CDR is 4.6875e-06, for the CS is 3.515625e-06, and for the AFM-16 is 0.002025. Thus, the use of nonlinear complex discrete signals, in particular, CDS and KS, can significantly increase the noise immunity of signal reception in modern ICS. At the same time, taking into account the improved ensemble and structural properties of these nonlinear signals, it is possible to improve significantly the indicators of crypto- and imitation security of the systems functioning.

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Poliarus, Oleksandr, Iryna Nazarenko, Yevhen Poliakov, Andrii Lebedynskyi, and Sergii Ianushkevych. "Synthesis of the model of the socio-economic system." SHS Web of Conferences 67 (2019): 06041. http://dx.doi.org/10.1051/shsconf/20196706041.

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The identification of the socio-economic system, which includes the scientific and scientific-technical activities of Ukraine, using the three input and output signals, is carried out in the article. The synthesis of the model is based on the minimization of the functional, which is the distance in the functional space with the quadratic metric between the real output signal and the theoretical signal containing the unknown parameters of the system model. These parameters include the system time constant and the coefficients that describe the power transformation function of the nonlinear block. A comparison of real output signals and signals calculated using the linear model of the system with memory and the Hammerstein model for a nonlinear inertial model is carried out. It is shown that the errors of the output signals representation for the quadratic model are less than for the linear one and are different for various output signals. If these errors exceed the allowable ones, it is recommended to change the parameters of the model or the number of members of the power function of the nonlinear block transformation.

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Tsankov, Tsvetoslav, Tihomir Trifonov, and Lilia Staneva. "AN ALGORITHM FOR SYNTHESIS OF PHASE MANIPULATED SIGNALS WITH HIGH STRUCTURAL COMPLEXITY." Journal scientific and applied research 4, no. 1 (October 10, 2013): 80–87. http://dx.doi.org/10.46687/jsar.v4i1.84.

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In the paper an algorithm for synthesis of pseudo-noise signals with high structural complexity is presented. It is based on the possibility the elements of the finite algebraic fields to be generated by means of a linear recurring sequence with maximal length. The algorithm can be used in the development of communication systems with high resistance to hostile radio-electronic environment.

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Dow, J. Maxwell, Yvonne Fouhy, Jean F. Lucey, and Robert P. Ryan. "The HD-GYP Domain, Cyclic Di-GMP Signaling, and Bacterial Virulence to Plants." Molecular Plant-Microbe Interactions® 19, no. 12 (December 2006): 1378–84. http://dx.doi.org/10.1094/mpmi-19-1378.

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Cyclic di-GMP is an almost ubiquitous second messenger in bacteria that was first described as an allosteric activator of cellulose synthase but is now known to regulate a range of functions, including virulence in human and animal pathogens. Two protein domains, GGDEF and EAL, are implicated in the synthesis and degradation, respectively, of cyclic di-GMP. These domains are widely distributed in bacteria, including plant pathogens. The majority of proteins with GGDEF and EAL domains contain additional signal input domains, suggesting that their activities are responsive to environmental cues. Recent studies have demonstrated that a third domain, HD-GYP, is also active in cyclic di-GMP degradation. In the plant pathogen Xanthomonas campestris pv. campestris, a two-component signal transduction system comprising the HD-GYP domain regulatory protein RpfG and cognate sensor RpfC positively controls virulence. The signals recognized by RpfC may include the cell-cell signal DSF, which also acts to regulate virulence in X. campestris pv. campestris. Here, we review these recent advances in our understanding of cyclic di-GMP signaling with particular reference to one or more roles in the bacterial pathogenesis of plants.

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DEBBAL, S. M., F. BEREKSI-REGUIG, and A. MEZIANE TANI. "THE FAST FOURIER TRANSFORM AND THE CONTINUOUS WAVELET TRANSFORM ANALYSIS OF THE PHONOCARDIOGRAM SIGNAL." Journal of Mechanics in Medicine and Biology 04, no. 03 (September 2004): 257–72. http://dx.doi.org/10.1142/s0219519404001028.

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This paper is concerned with a synthesis study of the fast Fourier transform (FFT) and the continuous wavelet transform (CWT) in analysing the phonocardiogram signal (PCG). It is shown that the continuous wavelet transform provides enough features of the PCG signals that will help clinics to obtain qualitative and quantitative measurements of the time-frequency PCG signal characteristics and consequently aid to diagnosis. Similary, it is shown that the frequency content of such a signal can be determined by the FFT without difficulties.

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Wang, Di, Jia Jun Zhou, Song Chen, Ying Yao, Liang Yin, and Xiao Wei Liu. "Design of the Digital in Signal Processing Platform of the Gyroscope Based on FPGA." Key Engineering Materials 609-610 (April 2014): 903–7. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.903.

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Gyroscope is a sensor thatmeasure angular velocity which is widely used in various fields [1]. The analogprocessing technology of Gyro-signal is very mature, but due to the noise andother shortcomings of the analog circuit, the development of micro-mechanical gyroscopeis limited. Digital gyroscope has superior performance and accuracy, so thesignal processing of gyroscope will take digital methods [2]. This paper designsa platform for the digital signal processing of Silicon gyroscope. By using FPGAextend A / D and D / A interface method implement the signals from outside inputto output, build a digital signal processing platform of the minimum system,then design the overall digital signal of the hardware part and the controlsection of the software part, synthesis the designed platform which doesn’tdepend on crafts use the Xilinx Synthesis tool and gave the synthesizedresults, verify the correctness of the design eventually.

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Raja Abdullah, Saleh, Syed Abdul Rahman, Zamri, and Rashid. "Texture Classification Using Spectral Entropy of Acoustic Signal Generated by a Human Echolocator." Entropy 21, no. 10 (October 2, 2019): 963. http://dx.doi.org/10.3390/e21100963.

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Human echolocation is a biological process wherein the human emits a punctuated acoustic signal, and the ear analyzes the echo in order to perceive the surroundings. The peculiar acoustic signal is normally produced by clicking inside the mouth. This paper utilized this unique acoustic signal from a human echolocator as a source of transmitted signal in a synthetic human echolocation technique. Thus, the aim of the paper was to extract information from the echo signal and develop a classification scheme to identify signals reflected from different textures at various distance. The scheme was based on spectral entropy extracted from Mel-scale filtering output in the Mel-frequency cepstrum coefficient of a reflected echo signal. The classification process involved data mining, features extraction, clustering, and classifier validation. The reflected echo signals were obtained via an experimental setup resembling a human echolocation scenario, configured for synthetic data collection. Unlike in typical speech signals, extracted entropy from the formant characteristics was likely not visible for the human mouth-click signals. Instead, multiple peak spectral features derived from the synthesis signal of the mouth-click were assumed as the entropy obtained from the Mel-scale filtering output. To realize the classification process, K-means clustering and K-nearest neighbor processes were employed. Moreover, the impacts of sound propagation toward the extracted spectral entropy used in the classification outcome were also investigated. The outcomes of the classifier performance herein indicated that spectral entropy is essential for human echolocation.

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Boiko, Juliy, Lesya Karpova, Oleksander Eromenko, and Yevhen Havrylko. "Evaluation of phase-frequency instability when processing complex radar signals." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 4 (August 1, 2020): 4226. http://dx.doi.org/10.11591/ijece.v10i4.pp4226-4236.

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A new radar system for digital signal processing before detection is proposed. These are the guidelines for selecting an intermediate frequency for signal processing. The features of signal processing in the case of echo-signal selection by the features of the correlation properties of their complex bypass are described. This paper presents the study of ambiguity function (AF) when processing complex radar signals. In this work, the AF synthesis was performed considering non-determined components and the presence of phase-frequency instability. The received result enhances the potentials for distinguishing an incoherent radar signal. The numerical simulation results of received AF are presented. Considering fluctuation components in the complex AF, depending on the laws of the distribution of amplitude and frequency fluctuations and their parameters, allowed to get the gain in the width of the main lobe from the units to tens of times. Paper represents original analytical expressions for AF of radio-signals modulated by narrow band random processes with various distribution laws.

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Qi, Jian, Qun Sun, Xiaoliang Wu, Chong Wang, and Linlin Chen. "Design and Analysis of a Low Cost Wave Generator Based on Direct Digital Synthesis." Journal of Electrical and Computer Engineering 2015 (2015): 1–17. http://dx.doi.org/10.1155/2015/367302.

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Signal generators are widely used in experimental courses of universities. However, most of the commercial tests signal generators are expensive and bulky. In addition, a majority of them are in a fixed working mode with many little-used signals. In order to improve this situation, a small sized and highly accurate economic signal generator based on DDS technology has been developed, which is capable of providing wave signals commonly used in experiments. Firstly, it is introduced the basic principles of DDS and is determined the overall scheme of the signal generator. Then, it proposes a design of the hardware, which include power supply module, display module, keyboard module, waveform generating module based on DDS chip, and the minimum system module based on C8051F010. The signal generator was designed to output sine and square waveforms, and the other achieved performances included the frequency range 0.1 Hz–12.5 MHz, the frequency resolution 0.05 Hz–0.1 Hz, the output amplitude 1.0–4.5 V, the frequency accuracyKfmin=94.12% andKfmax=99.99%, and the signal distortionRTHDmin=0.638% andRTHDmax=11.67%.

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Худов, Г. В., Сальман Рашід Оваід, В. М. Ліщенко, and В. О. Тютюнник. "Methods of signal processing in a multiradar system of the same type of two-coordinated surveillance radars." Системи обробки інформації, no. 3(162), (September 30, 2020): 65–72. http://dx.doi.org/10.30748/soi.2020.162.07.

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The subject of research in the paper is the problem of developing methods of signal processing in a multiradar system of the same type of two-coordinate surveillance radars with mechanical rotation. The aim of the paper is to improve the quality of detection of air objects by combining the same type of two-coordinate radars in a multi-radar system. It is proposed to combine the existing surveillance radar stations into a spatially spaced coherent multi-radar system. The synthesis of optimal detectors of coherent and incoherent signals is carried out. The characteristics of detection of air objects in a multi-radar system with compatible signal receiving have been evaluated. The obtained results: the addition of the second radar, regardless of the degree of signal coherence, showed the greatest efficiency in the gain in terms of signal / noise, the optimal number of radars in the multi-radar system is not more than four. The expected signal / noise threshold gain in a system of four radars can be up to eighteen decibels for a system with coherent signals and up to eleven decibels for a system with incoherent signals. The using of more than four radars is impractical.

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37

Suzuki, Harumi, Yoichi Shinkai, Lawrence G. Granger, Frederick W. Alt, Paul E. Love, and Alfred Singer. "Commitment of Immature CD4+8+ Thymocytes to the CD4 Lineage Requires CD3 Signaling but Does Not Require Expression of Clonotypic T Cell Receptor (TCR) Chains." Journal of Experimental Medicine 186, no. 1 (July 7, 1997): 17–23. http://dx.doi.org/10.1084/jem.186.1.17.

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As a consequence of positive selection in the thymus, immature CD4+8+ double-positive, [DP] thymocytes selectively terminate synthesis of one coreceptor molecule and, as a result, differentiate into either CD4+ or CD8+ T cells. The decision by individual DP thymocytes to terminate synthesis of one or the other coreceptor molecule is referred to as lineage commitment. Previously, we reported that the intrathymic signals that induced commitment to the CD4 versus CD8 T cell lineages were markedly asymmetric. Notably, CD8 commitment appeared to require lineage-specific signals, whereas CD4 commitment appeared to occur in the absence of lineage-specific signals by default. Consequently, it was unclear whether CD4 commitment, as revealed by selective termination of CD8 coreceptor synthesis, occurred in all DP thymocytes, or whether CD4 commitment occurred only in T cell receptor (TCR)–CD3-signaled DP thymocytes. Here, we report that selective termination of CD8 coreceptor synthesis does not occur in DP thymocytes spontaneously. Rather, CD4 commitment in DP thymocytes requires signals transduced by either CD3 or ζ chains, which can signal CD4 commitment even in the absence of clonotypic TCR chains.

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Szczepaniak, Zenon, and Tomasz Rogala. "Reduction of Spurious Signal Upconversion in Frequency Multipliers." Electronics 9, no. 7 (July 10, 2020): 1126. http://dx.doi.org/10.3390/electronics9071126.

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Usually many applications of radar transceivers and heterodyne frequency synthesizers assume a spurious signal power level below −60 dBc. In the case of modern synthesizers using direct digital synthesis (DDS) systems, the number of emerging spurious signal frequencies is very large, and spectral purity within −60 dBc can only be obtained in the relatively narrow tuning band of the DDS unit. For the purposes of widening this useful frequency range, the frequency multiplying operation is applied commonly. Then, during the process of frequency multiplication of the baseband signal containing inband spurious signals, the effect of the upconversion of spurious signals occurs. The paper contains an analysis of the undesirable effects of the conversion of spurious signal frequencies accompanying the process of frequency multiplication. A method of reducing the level of upconverted spurious signals is proposed. The numerical calculations and measurement results are provided. For the case of a frequency multiplier with a multiplying factor equal to N, the power ratio between the desired output signal and upconverted spurious signal drops by an additional 1/N2. It has been found that the application of the presented method during the design process of the frequency multiplier allows this ratio to be improved by 6 dB.

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Hadi Mohammad, Alaa, Azura Che Soh, Noor Faezah Ismail, Ribhan Zafira Abdul Rahman, and Mohd Amran Mohd Radzi. "Improvement of LMS adaptive noise canceller using uniform Poly-phase digital filter bank." Indonesian Journal of Electrical Engineering and Computer Science 17, no. 3 (March 1, 2020): 1258. http://dx.doi.org/10.11591/ijeecs.v17.i3.pp1258-1265.

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<span>This paper presents the Least Mean Square (LMS) noise canceller using uniform poly-phase digital filter bank to improve the noise can-cellation process. Analysis filter bank is used to decompose the full-band distorted input signal into sub-band signals. Decomposition the full-band input distorted signal into sub-band signals based on the fact that the signal to noise ratio (S/N) is inversely proportional to the signal bandwidth. Each sub-band signal is fed to individual LMS algorithm to produce the optimal sub-band output. Synthesis filter bank is used to compose the optimal sub-band outputs to produce the final optimal full-band output. In this paper, m-band uniform Discrete Fourier Transform (DFT) digital filter bank has been used because its computational complexity is much smaller than the direct implementation of digital filter bank. The simulation results show that the proposed method provides the efficient performance with less and smooth error signal as compared to conventional LMS noise canceller.</span>

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Bahoura, Mohammed. "Efficient FPGA-Based Architecture of the Overlap-Add Method for Short-Time Fourier Analysis/Synthesis." Electronics 8, no. 12 (December 12, 2019): 1533. http://dx.doi.org/10.3390/electronics8121533.

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This paper proposes a simple and efficient FPGA-based architecture of the overlapping/windowing and overlap-add methods for real-time FFT/IFFT-based signal processing algorithms. The analyzed signal is divided into short-time overlapping frames that are windowed before applying Fourier analysis/synthesis. Then, the original signal is reconstructed from the windowed (modified) frames using the overlap-add (OLA) technique. The proposed architecture was implemented on Field Programmable Gate Array (FPGA) using a high-level programming tool in MATLAB/SIMULINK environment. Its performance was evaluated on artificial and actual signals using objective metrics.

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DUMAURIER, Marie-Jeanne, Claudette PELASSY, Jean-Philippe BREITTMAYER, and Claude AUSSEL. "Regulation of the serine-base exchange enzyme system by CD4: effects of monoclonal antibodies, jacalin, interleukin 16 and the HIV membrane protein gp120." Biochemical Journal 329, no. 1 (January 1, 1998): 49–54. http://dx.doi.org/10.1042/bj3290049.

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Phosphatidylserine (PtdSer) is synthesized by an exchange of the polar head group of phospholipids for a serine residue. The enzyme responsible for this reaction, the serine-base exchange enzyme system (serine-BEES) is inhibited during lymphocyte activation. We show here that triggering the CD4 cell surface molecule in several CD4+ T-cell lines regulates the serine-BEES activity, thus resulting in marked changes in PtdSer synthesis. CD4 ligands able to generate an activating signal in T-cells such as the lectin jacalin, down-regulate the synthesis of PtdSer. In contrast, monoclonal antibodies (mAbs) directed against the CD4 molecule, such as IOT4 and IOT4a, which have previously been described as generating an inhibitory signal to T-cells, induced an up-regulation of the serine-BEES and impaired CD3-induced inhibition of PtdSer synthesis. Similarly, the HIV-gp120 envelope glycoprotein, in both soluble and cross-linked forms, induces an increase in PtdSer synthesis. The protein tyrosine kinase p56lck participates in the regulation of serine-BEES activity because the effect of CD4 mAbs was additive to that of amino-hydroxyflavone, an inhibitor of p56lck. Also, CD4 mAbs were inactive in J Cam 1.6 cells or when the CD3 signals were bypassed by using thapsigargin. These results demonstrate that the CD4 surface molecule can transmit both activating and inhibiting intracellular signals depending on the CD4 ligand used. We suggest that PtdSer synthesis would be one of the intracellular signals that could explain the opposite effects of different CD4 ligands on T-cells.

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Gao, Cheng Fang, Xiao Meng Wu, and Jia Tian Zhang. "Improvement Hardware Design of High Power and Ultra-Low Frequency Signal Source in Cased Hole Resitivity Logging." Applied Mechanics and Materials 397-400 (September 2013): 2278–81. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.2278.

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The cased hole resistivity logging technology is one of high-tech logging technologies being studied in China. The signal source requires high voltage, high current, ultra-low frequency, high stability, high resolution, etc. Based on the characteristics, proposed were the ideas that the direct digital synthesis technique should be applied to produce the required sine logging exciting signals, and high-power FET were used to produce the signals with high power and high voltage. The results show that the output frequency of signal source is 0~ 10 Hz, frequency resolution 0. 002 Hz, output voltage range -300 V~+300V, output current less than 6 A. The design has been successfully applied in the research project of extremely weak nV-level electric signal acquisition theory and experimental study on formation resistivity measurement through metal casing.

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Choi, Jee Woong. "Target Signal Simulation in Synthetic Underwater Environment for Performance Analysis of Monostatic Active Sonar." JOURNAL OF THE ACOUSTICAL SOCIETY OF KOREA 32, no. 6 (2013): 455. http://dx.doi.org/10.7776/ask.2013.32.6.455.

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Zheng, Fang Yan, Zi Ran Chen, and Ji Sen Yang. "Design of Current-Model Signal Source of Time Grating with Self-Compensation Technology." Advanced Materials Research 590 (November 2012): 431–35. http://dx.doi.org/10.4028/www.scientific.net/amr.590.431.

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The measurement precision of time grating sensors is influenced by the phase symmetrical characteristic of three-phase exciting signal source. Therefore, a novel current-model exciting signal source with self-compensation technology is presented. In order to obtain high precision phase symmetry in stability, three orthogonal sine signals are generated by direct digital frequency synthesis (DDS) technology with self-checking and self-collection. Experiment results prove that the stability and measurement precision are improved significantly.

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Sharko, Artem. "MODELS AND METHODS OF PROCESSING OF INFORMATION ON LOADS OF ACOUSTIC SIGNALS IN TECHNICAL DIAGNOSTIC SYSTEMS." Informatyka Automatyka Pomiary w Gospodarce i Ochronie Środowiska 8, no. 3 (September 25, 2018): 15–18. http://dx.doi.org/10.5604/01.3001.0012.5276.

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The paper presents one-dimensional discrete-continuous model of power spectrum estimation of the acoustic emission signal, that allows filtering the oscillating components of the acoustic emission signals. The mathematical formalism describing the environment was discussed, initiating the signals of acoustic emission. The problem of spectral analysis and synthesis of acoustic emission signals was solved with the help of Fourier transform. The dependence of acoustic vibrations spectra on the size of the medium parameters and microstructure has been discussed, as well.

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Dubyna, O. F., O. V. Andreiev, T. M. Nikitchuk, I. V. Puleko, S. S. Hatsenko, and V. V. Kliaznyka. "SYNTHESIZING THE ANTENNA APERTURE USING SIGNALS FROM GROUND-BASED RADAR STATIONS FROM A SPACE CARRIER." Проблеми створення, випробування, застосування та експлуатації складних інформаційних систем, no. 22 (August 4, 2022): 69–78. http://dx.doi.org/10.46972/2076-1546.2022.22.06.

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Today, one of the priority directions of the aerospace industry of Ukraine is the creation of effective aerospace intelligence. Remote sensing of the Earth in the optical range provides the opportunity to obtain images of the Earth's surface for use in the military sphere and the national economy. For this, various sensors are used, which, as a rule, register radiation reflected from the surface of the Earth and objects located on it. Surveying the Earth's surface from space vehicles in the radio range allows solving a wide range of tasks. At the same time, the antenna irradiates the earth's surface with a radio signal with known parameters and receives the signal reflected from the surface over a relatively large area of the carrier's trajectory. When using a side view of the earth's surface to increase the angular separation by the path range, the artificial synthesis of the antenna aperture has become widely used. Artificially synthesizing the antenna aperture is carried out at the stage of coherent or incoherent processing of the reflected signal on a certain section of the carrier's trajectory. At the same time, the parameters of the reference trajectory signal are considered to be known with accuracy to the random phase. In contrast to the classical active methods of antenna aperture synthesis, which require the availability of information about the parameters of the radiated signal, with the passive method of antenna aperture synthesis, the parameters of the received signal are determined by the type of radio radiation source and are a priori unknown. When passively synthesizing the antenna aperture based on ground radar signals, both the maximum possible size of the synthesized aperture and the conditions for determining the azimuthal direction to the source of radio radiation depend on the parameters of the signal emitted by the radar. The paper analyzes the orbit parameters of the spacecraft, which ensure the fulfillment of the condition of the unambiguity of the determination of the azimuthal direction to the source of radio radiation and determine the resolution in terms of the path range during the passive synthesis of the antenna aperture based on the signals of typical radars operating in the pulse mode. Keywords: spacecraft; source of radio emission; resolution; antenna synthesized aperture.

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Zhilyakov, Evgeny G., Sergei P. Belov, Ivan I. Oleinik, Sergei L. Babarinov, and Diana I. Trubitsyna. "Generalized sub band analysis and signal synthesis." Bulletin of Electrical Engineering and Informatics 9, no. 3 (June 1, 2020): 964–72. http://dx.doi.org/10.11591/eei.v9i3.1709.

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Currently, one of the main approaches used in analyzing properties and synthesis of signals in various classes is the subband methodology, which is carried out from the position of Fourier transform of signal samples (frequency representations) into subbands of the transform definition domain (transformants). In this case, the main tool, which is widely used for subband analysis (including wavelet analysis), is usage of bandpass filters (mainly those with finite impulse response or FIR filters). The present paper introduces the basics of building a theory forsubband analysis / signal synthesis for various classes, and using transformations based on any orthonormal basis with weight. This proposed approach is based on the concept of Euclidean signal norm square fraction in a given subband of the transformant definition domain. It is shown that the basis for mathematical apparatus of subband analysis is a new class of matrices, called subband ones. Some eigenvalue properties of these matrices are established, and the problem of optimal selection for additive signal components is formulated and solved

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Zhuang, X. D., H. Zhu, and N. E. Mastorakis. "Signal Processing: New Stochastic Feature of Unvoiced Pronunciation for Whisper Speech Modeling and Synthesis." International Journal of Circuits, Systems and Signal Processing 14 (January 15, 2021): 1162–75. http://dx.doi.org/10.46300/9106.2020.14.144.

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Whisper is an indispensable way in speech communication, especially for private conversation or human-machine interaction in public places such as library and hospital. Whisper is unvoiced pronunciation, and voiceless sound is usually considered as noise-like signals. However, unvoiced sound has unique acoustic features and can carry enough information for effective communication. Although it is a significant form of communication, currently there is much less research work on whisper signal than common speech and voiced pronunciation. Our work extends the research of unvoiced pronunciation signal by introducing a novel signal feature, which is further applied in unvoiced signal modeling and whisper sound synthesis. The statistics of amplitude for each frequency component is studied individually, based on which a new feature of “consistent standard deviation coefficient” is revealed for the amplitude spectrum of unvoiced pronunciation. A synthesis method for unvoiced pronunciation is proposed based on the new feature, which is implemented by STFT with artificially generated short-time spectrum with random amplitude and phase. The synthesis results have identical quality of auditory perception as the original pronunciation, and have similar autocorrelation as that of the original signal, which proves the effectiveness of the proposed stochastic model of short-time spectrum for unvoiced pronunciation

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Schrader, C. E., J. Stavnezer, H. Kikutani, and D. C. Parker. "Cognate T cell help for CD40-deficient B cells induces c-myc RNA expression, but DNA synthesis requires an additional signal through surface Ig." Journal of Immunology 158, no. 1 (January 1, 1997): 153–62. http://dx.doi.org/10.4049/jimmunol.158.1.153.

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Abstract To investigate the role of CD40 ligand in the delivery of help to B cells, we examined the Ag-specific interaction of B cells from CD40-deficient mice with a Th2 cell line in vitro. Small resting B cells from normal mice are stimulated to synthesize DNA when they present monovalent Ag (rabbit Fab anti-Ig) to a rabbit Ig-specific Th cell line. This response, which is independent of a signal through the B cell Ag receptor (sIg), is nearly absent in B cells from CD40-deficient mice. The CD40-deficient B cells are not defective in Ag presentation because they induce T cell IL-4 synthesis as well as normal B cells. Also, CD40-deficient B cells respond to T cell help with DNA synthesis almost as well as normal B cells if an additional signal is provided through sIg. In conjunction with a sIg signal, cell contact with helper T cells induces DNA synthesis more effectively than soluble cytokines. CD40-independent T cell help can also be measured as an early increase in c-myc mRNA levels in CD40-deficient B cells presenting Ag to helper T cells, although the levels of c-myc RNA expression are lower than those in normal B cells. However, c-myc RNA induced by noncognate interaction with anti-CD3-activated T cells is completely CD40 dependent. We conclude that early growth signals from activated Th cells are received by CD40-/- B cells, but that CD40 and/or sIg signals are required for efficient induction of DNA synthesis.

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Yin Feifei, 尹飞飞, 尹子恺 Yin Zikai, 谢祥芝 Xie Xiangzhi, 戴一堂 Dai Yitang, and 徐坤 Xu Kun. "基于双光学频梳的超宽带射频信号信道化合成技术研究（特邀）." Infrared and Laser Engineering 50, no. 7 (2021): 20211054. http://dx.doi.org/10.3788/irla20211054.

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Journal articles on the topic 'Signal synthesi'

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