Digital technologies

RESULTS OF MODELING, DESIGNING AND DEVELOPMENT OF BAND-PASS ELECTRIC FILTER WITH CROSS-LINKS IN WIDE RANGE OF ULTRA HIGH FREQUENCY BANDS

T.M. Narytnyk , V.I. Korsun , V.F. Korsak , A.B. Borysko, A.V. Vovkotrub — Thu, 01 Apr 2021 00:00:00 +0300

The provided analysis shows the need to ensure non-interference operation of radio electronic facilities (REFs) by eliminating the incompatible radio technologies in the adjacent frequency bands or by minimizing interference as far as possible. A presented example based on the cellular communication systems suggests that one of the factors influencing the size of a guard interval is the need to ‘filter-out’ nearby radio technologies operating in opposite directions of transmission. In such instances, filters shall be used to avoid interference. Filters will allow, in the first place, to create necessary attenuation in the reception band of BS of nearby radio technology to suppress out-of-band and spurious emissions, furnishing by BS own transmitter; and in the second place, to create attenuation in the transmission band of nearby radio technology in order to reduce signals coming from BS transmitters of nearby radio technology at the input of own BS receiver. Additional high slope AFR filters may be required for both the BS transmitters and BS receivers in some frequency ranges in Ukraine. There is one more precondition for usage of high slope AFR filters having the ability to suppress main emission of transmitters by values of 30-40 dB as follows: appropriate radio frequency control and regulatory authorities are required to apply the measuring equipment within dynamic range of 80 dB. The simplified 3D filter models on 9 coaxial resonators with high Q factor which are described in the article are prepared with the help of AWR Microwave office and CST Studio Suite software tools. The simulation of AFR and frequency response for such parameter as filter reflection coefficient is also described in the article. The results of design and research concerning band-pass electric filters that have been obtained on the basis of application of the low-frequency filter prototype method are presented in the article. Prototype models of band-pass electric filters with cross-links in wide range of UHF bands (820–843 MHz and 890–915 MHz, 1920–1980 MHz and 2510–2570 MHz) are designed and produced. As a result of measurements of AFR and frequency response for the filter reflection coefficient, the attenuation within the pass-band frequency range of these filters equals to 1.5–2.0 dB; the attenuation of input signals referring to out-of-band emissions equals to 30–75 dB; the filter reflection coefficient is within minus 13 dB.

SATELLITE SEGMENT OF NATIONAL INFORMATION INFRASTRUCTURE. APPROACHES TO IMPLEMENTATION

A.M. Melnyk — Thu, 01 Apr 2021 00:00:00 +0300

. It is proved that the satellite segment is a necessary component of the national information infrastructure. From this position, the state and development trends of satellite telecommunication systems and satellite channel organization technologies are analyzed. It is shown that there are two ways to build a satellite segment: based on the use of leased resources of satellite operators operating in the satellite communications market; based on the resources of the national satellite communications system, which still needs to be created. It is shown that satellite telecommunication systems have a steady tendency to increase the number of spacecraft, until the launch of “heavyˮ satellites with a payload of more than 70 transponders and to increase the frequency resource. The diagram of satellites location density of in orbit is given. In the case of orientation to rent the resources of active spacecraft, the criteria for their selection is indicated. The arc of the geostationary orbit, on which the satellite should be selected, is calculated. For satellites located on this arc, diagrams of equivalent isotropically radiated power values in the C and Ku bands, which they provide in Ukraine, are shown. A list of satellites that you can focus on, recommendations for selection and a list of recommended for the satellite segment is indicated. The technology standards used in payload and methods for organizing satellite communications channels is noticed. To select the parameters of the satellite segment, the results of calculations of the effectiveness of signal-code structures are provided. Approaches to creating a satellite segment of the national information infrastructure are proposed. It is shown that the orientation to the Lybid national satellite does not make sense; a new frequency-orbit resource is required. The types of platforms that can be used on a national satellite are considered.

POTENTIALLY ACHIEVABLE LEVEL IMAGE DEFINITION IN VIDEO APPLICATIONS

S.M. Kiiko, O.V. Gofaizen — Thu, 01 Apr 2021 00:00:00 +0300

The paper gives an estimate of the potentially achievable level of definition for light-to-light video transmission path, which can be considered as ideal, i.e. such that a decrease in definition in it occurs only due to the diffraction limitations of the camera lens and the finite dimensions of the transforming elements of the camera matrix sensor and of the reproducing display without additional image processing. Examples of MTF of end-to-end paths for SDTV, HDTV, UHDTV 4K and UNDTV 8K systems for the specified parameters of the lens and camera sensor, taking into account the distortions introduced by the reproducing display, are presented.

IMAGE RESTORATION METHOD, INVARIANT TO SIGNAL CORRELATION IN THE INFORMATION SYSTEM WITH ADAPTIVE ANTENNA ARRAY

V.V. Skachkov, O.V. Tkachuk — Thu, 01 Apr 2021 00:00:00 +0300

The problem of image signal processing in the information system with adaptive antenna array based on the inversion of sample estimates of correlation matrix of observations is considered. The example of the maximum signal-to-noise ratio criterion shows the problem, inherent in classical methods of finding the optimal weight vector under a priori uncertainty conditions when detecting correlated image signals. It has been concluded that the dependence of these methods on the inverse of estimation of the correlation matrix of observations leads to the impossibility of separating correlated image signals. As a consequence, the use of classical methods of finding the optimal weight vector in the information system with adaptive antenna array is effective only in the case of image restoration from a single signal source, with the signal received on the set of independent jamming background. A novel method, invariant to the correlation of image signals, has been developed for finding the optimal weight vector without the usage of correlation matrix of observations. An image restoration algorithm invariant to correlation of image signals in the information system with adaptive antenna array is proposed. Statistical models have been constructed for the classical method based on the criterion of maximum signal-to-noise ratio and invariant to correlation method of image restoration in following cases: a single source against the jamming background of two independent sources; two independent sources against the jamming background. Simulation results in the information system with adaptive antenna array are presented, showing to visually assess efficiency of proposed methods of image signal restoration using optimal weight vector. Detailed analysis of the results obtained is carried out.

FEATURES OF PLANNING SINGLE-FREQUENCY NETWORKS OF DIGITAL RADIO BROADCASTING TO COVER ROADS

D.O. Makoveyenko , O.А. Vykhodets , O.S. Koltsova — Thu, 01 Apr 2021 00:00:00 +0300

An analysis of the world experience in the using of broadcasting networks has shown, that currently the most common digital terrestrial broadcasting technology in Europe is DAB / DAB +. The paper considers the results of research on the construction of a single-frequency synchronous network using DAB+ technology for coverage of highways on the example of the Kyiv - Odessa road. The influence of the network amplification effect is considered and quantitative estimates of the total gain in the statistical addition of signals from two transmitters are obtained. For the practical evaluation of the statistical network gain, control points are selected on the section of the route, where the predicted level of field strength from one transmitter is lower than the required value. Using the k-LNM method, it is determined that the resulting predicted value of the field strength exceeds the minimum required, and the corresponding probability of reception in all cases is greater than 99%. The radio coverage parameters of the reception were modeled, according to Recommendation ITU-R P.1812. A comparison of analog and digital radio coverage for the Kyiv-Odessa route showed that coverage in digital broadcasting mode for a 99% probability of reception is better than for analog broadcasting without installing additional transmitters or increasing the power used in analog broadcasting planning.

COMBINING DAB + DIGITAL BROADCASTING TECHNOLOGY AND 5G TECHNOLOGY FOR THE DISTRIBUTION OF AUDIO PROGRAMS CONTENT

O.P. Serman — Thu, 01 Apr 2021 00:00:00 +0300

The option of distributing of digital audio broadcasting programs using traditional DAB + broadcasting technology and 5G mobile communication technology is considered. It is proposed to use the mobile network as a transport network to deliver content to low-power digital broadcasting transmitters operating as single-frequency network. A review of typical configurations of radio and mobile networks is done, and it is noted that using the high and medium power transmitter networks it is quite difficult to provide high-quality reception on portable and car receivers, especially in large cities with dense buildings. To eliminate areas where reception is absent, it is proposed to install additional low-power receivers, to which the content will be distributed via mobile networks.