Volume 4, Number 3 (2018)
I.V. Ryabov, N.V. Degtyarev, E.S. Klyuzhev
DIGITAL COMPUTER SYNTHESIS OF FREQUENCY-MODULATED SIGNALS (pp. 3-6)
V.G. Sannikov, A. Korolkov
METHOD OF CLEARING THE SPEECH SIGNAL FROM NOISE BASED ON THE PSYCHOACOUSTIC MODEL OF ITS HEARING (pp. 7-11)
N.I. Smirnov, S.V. Melnik, E.N. Petrova
COMPACT TIME SERVER FOR SYNCHRONIZATION IN THE INTERNET OF THINGS NETWORK (pp. 12-15)
D.M. Soloviev, L.N. Kazakov
OPTIMIZATION OF COMPUTER RESOURCES OF A MULTI-BEAM RADIO CHANNEL SIMULATOR WITH FREQUENCY-TEMPOR SCATTERING (pp. 16-19)
V.P. Afanasyev, T. Korolkova
RESTORATION AND CLASSIFICATION OF TWO-DIMENSIONAL IMAGES BY ONE-DIMENSIONAL OBSERVATIONS (pp. 20-24)
FREQUENCY AND TIME SYNCHRONIZATION ALGORITHM FOR RECEIVING OFDM SIGNALS ON MIMO COMMUNICATION CHANNELS (pp. 24-29)
O.V. Biryukova, I.V. Koretskaya
ORGANIZATION OF WORK WITH EXTERNAL MEMORY WHEN CARRYING OUT MEASUREMENTS CHANGING DURING PHYSICAL VALUES DURING (pp. 30-36)
ABSTRACTS & REFERENCES
DIGITAL COMPUTER SYNTHESIS OF FREQUENCY-MODULATED SIGNALS
I.V. Ryabov, N.V. Degtyarev, E.S. Klyuzhev,
Volga State Technological University, Yoshkar-Ola, Russia
A new structure of a digital computer synthesizer of frequency-modulated signals is considered, which has increased speed and with the possibility of operational control of the initial frequency, which can be used in modern adaptive communication systems with pseudo-random tuning of the operating frequency. The purpose of the work is to increase speed and provide operational control of the initial frequency of the synthesized signal.
1. Ryabov I.V. Direct digital synthesis of precision signals. Yoshkar-Ola: MarSTU. 2005. 152 p.
2. Ryabov I.V. Direct digital synthesis of complex broadband signals for radar, navigation and communications. Yoshkar-Ola: PSTU. 2016. 151 p.
3. Ryabov I.V., Dedov A.N., Tolmachev S.V., Chernov D.A., Mishakov A.A. Patent No. 2566962 of the Russian Federation. IPC H03B 19/00, H03L 7/18. Digital computer synthesizer of frequency-modulated signals. Claim 04/15/2014. Publ. 10/27/2015. Bull. No. 30.
METHOD OF CLEARING THE SPEECH SIGNAL FROM NOISE BASED ON THE PSYCHOACOUSTIC MODEL OF ITS HEARING
V.G. Sannikov, A. Korolkov,
Moscow Technical University of Communications and Informatics, Moscow, Russia
A modernized method of spectral subtraction was developed and experimentally studied when speech was purified from noise. The novelty of the method is the use of a model of auditory perception of noisy speech on the periphery of the hearing. The proposed method and algorithm for its implementation allow for a signal-to-noise ratio of -10 dB and intelligibility up to 19% filtering (communication failure) to increase speech intelligibility after filtering up to 50%. This, according to GOST R 51061-97, allows you to use codecs with filtering according to this method for working in public telephone networks that provide a quality class for syllabic intelligibility not lower than the first and second.
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8. Sannikov V.G., Maslov S.N., Korolkov A.A. Estimation of the cutoff frequency of the low-frequency equivalent of a telephone communication channel during random observation. T-Comm. 2013. Vol. 7. No. 8, pp. 112-114.
COMPACT TIME SERVER FOR SYNCHRONIZATION IN THE INTERNET OF THINGS NETWORK
N.I. Smirnov, S.V. Melnik,
Scientific and Technical Center KOMSET , Moscow, Russia
An approach to providing time synchronization in the Internet of things (IoT) using compact time servers is described. The proposed method of time synchronization can improve the reliability of the network in the absence of a permanent communication channel between the network core and the remote domain. When connecting a large number of sensors on the Internet of things, capillary network structures are used. Remote domains of capillary networks may not be permanently connected to the main network, but may communicate through specially organized gateways. This allows several times (3-10) to reduce the amount of signaling traffic and thereby significantly increase the efficiency of use of a segment of a mobile communication network. When processing information from remote sensors in this case, data binding to the timeline is required. If you use the centralized method of distributing time stamps, then with a long absence of a signal from a central source, an error will accumulate. It is advisable to use inexpensive compact time servers connected to the gateways of the capillary network domain.
1. Smirnov N.I., Melnik S.V., Petrova E.N. Using a distributed synchronization scheme in 4G and 5G mobile communication networks. Synchronization, signal generation and processing systems. 2014. No.2, pp. 50-53.
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OPTIMIZATION OF COMPUTER RESOURCES OF A MULTI-BEAM RADIO CHANNEL SIMULATOR WITH FREQUENCY-TEMPOR SCATTERING
Simulators of multipath radio channels are the most important tools used by developers in modeling processes that occur at the physical level of wireless information transmission systems. Of greatest interest is the implementation of a fully digital hardware simulator. This type of simulators has several advantages compared to software, analog or analog-to-digital simulators: real-time operation with real signals, stability of characteristics, accuracy of radio channel parameters control, large dynamic range. The limiting factor in the use of digital simulators is the high computational costs, which lead to toughening requirements for the element base and increasing the cost of the product. An urgent problem in the implementation of the simulator is the solution of the problem of efficient use of a limited computing resource, which this work is devoted to.
1. Kazakov L.N., Soloviev D.M. Optimization of computing resources of a simulator of a mobile urban multipath radio channel. Elektrosvyaz. 2016. No.4, pp. 49-56.
2. Gerasimov A.B. Soloviev D.M. Implementation on FPGAs of a multipath channel simulator of high-speed mobile radio communication. Elektrosvyaz. 2014. No.5, pp. 39-43.
3. Kazakov L.N. Soloviev D.M. Calculation of the parameters of the urban multipath radio channel. Bulletin of Yaroslavl State University P.G. Demidov. A series of natural and technical sciences. 2014. No.4, pp. 19-24.
RESTORATION AND CLASSIFICATION OF TWO-DIMENSIONAL IMAGES BY ONE-DIMENSIONAL OBSERVATIONS
Recommendations are formulated on the implementation of the training stages and the operating mode when restoring two-dimensional images from one-dimensional observations. The review is carried out in relation to the task of classifying and restoring images of the earth’s surface when sighted with a weakly directed radar sensor. The following are discussed: a probabilistic model of the radar contrast field of the earth’s surface sections and a probabilistic model of observations at the input of a weakly directional sensor based on it, algorithms for classifying the earth’s surface and reconstructing a two-dimensional image of the sighted area. It is shown that the resolution of the reconstructed image is determined only by the resolution of the technical means used in the training mode. The above results allow generalization to the tasks of multi-user demodulation of signals in mobile communication systems.
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FREQUENCY AND TIME SYNCHRONIZATION ALGORITHM FOR RECEIVING OFDM SIGNALS ON MIMO COMMUNICATION CHANNELS
A.V. Bakke, firstname.lastname@example.org,
Ryazan State Radio Engineering University, Ryazan, Russia
The study was supported by a grant from the Russian Science Foundation (project 14-19-01263) at Ryazan State Radio Engineering University. Due to the high sensitivity of data transmission technology with OFDM modulation to time (Symbol Time Offset, STO) and frequency (Carrier Frequency Offset, CFO) mismatches special attention in OFDM communication systems is given to synchronization tasks. In multi-channel MIMO (Multiple Input Multiple Output) communication systems, the situation with symbolic and frequency synchronization is further aggravated by inevitable interference distortion, which imposes significant restrictions on the types of synchronizing signals and on the used synchronization methods.
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ORGANIZATION OF WORK WITH EXTERNAL MEMORY WHEN CARRYING OUT MEASUREMENTS CHANGING DURING PHYSICAL VALUES DURING
The article is devoted to testing related to the registration of a block of time-varying physical quantities in the field. The possibilities of generating signals for their transmission, storage and reproduction are considered. The research features of creating protocols for the exchange of information directly with a PC, SD-memory card and serial EEPROM memory. The main causes of malfunctions are identified. The developed flexible data management system was used when working with information received from the installation for static sensing. The method allows you to connect additional sensors and accumulate test statistics. According to the research results, the most promising when working in difficult conditions is the use of EEPROM memory chips with sequential access, as non-volatile, small-sized, easy to install and capable of more than a million rewriting cycles. Laboratory and field tests of the created equipment allow us to judge the operability and reliability of the proposed scheme. The method of obtaining and processing signals was used in equipment for static sensing, manufactured by LLC PIKA-TECHNOSERVICE Scientific and Technical Center.
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