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Tytuł:
Antenna Arrays Focused on Broadband Signals
Autorzy:
Vedenkin, D. A.
Sedelnikov, Y. E.
Nasybullin, A. R.
Powiązania:
https://bibliotekanauki.pl/articles/958050.pdf
Data publikacji:
2016
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
antenna array
broadband antenna
broadband signals
focusing on the broadband signals
Opis:
Broadband and ultra-wideband signals are increasingly used in modern radio systems. Traditional performance of evaluation antennas operating with narrowband signals are not always adequately reflect the characteristics of broadband antennas, at least in view of the frequency dependence of the antenna pattern. Accounting for broadband signals the antennas becomes important in the low-frequency range of the spectrum. Systems using these types of signals may include control of the atmosphere and measuring its frequency-selective properties in the range meter and decameter wavelengths. Possibility of spatial selection based on focusing of broadband signals in this case promises to implement a number of additional features. Therefore, it is important to evaluate the properties of antennas based on the spectral content of the signal, as well as taking into account the ways of its processing in the receiving equipment. Consideration features of functioning the antenna array, focused on broadband signal is devoted to this article.
Źródło:
Journal of Telecommunications and Information Technology; 2016, 2; 95-102
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of broadband speed on economic outputs: An empirical study of OECD countries
Autorzy:
Kongaut, Chatchai
Bohlin, Erik
Powiązania:
https://bibliotekanauki.pl/articles/943174.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Ekonomiczny w Poznaniu
Tematy:
broadband speed
broadband policy
GDP
OECD
Opis:
A number of studies have indicated that higher broadband penetration leads to greater economic impacts. Nevertheless other characteristics of broadband services such as different speeds are becoming more important to determine the economic impacts. This study estimates the relationship between broadband speed and economic outputs. The results show that broadband speed contributes positively to economic outputs such as GDP. The effects of broadband speed are also greater in countries with lower income. The policy recommendation is therefore that countries should focus on and encourage high speed broadband infrastructure and its adoption in their national broadband plans and policies.
Źródło:
Economics and Business Review; 2017, 3(17), 2; 12-32
2392-1641
Pojawia się w:
Economics and Business Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Internet infrastructure and its usage in poland and other european union member states
Autorzy:
Śledziewska, K.
Levai, A.
Zięba, D.
Powiązania:
https://bibliotekanauki.pl/articles/95083.pdf
Data publikacji:
2016
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
internet usage
broadband coverage
broadband speed
internet affordability
NGA
Opis:
One in four of all households in Poland does not have access to the Internet, while in the EU15, the same refers to only one in every six households. In this paper we analyze the Internet infrastructure from both supply (broadband coverage-speed) and demand (usage of Internet by individuals-SMEs) side, as well as the affordability aspect. In particular, we search for biggest gaps of Poland’s Internet infrastructure in comparison to other European Union Member States (EU15 and NMS12). Our empirical analysis is based on European Commission’s and ITU’s databases. Moreover, we provide some recommendations for the government and enterprises exposing the biggest gaps of Poland and emphasizing the beneficial impact of the Next Generation Access networks.
Źródło:
Information Systems in Management; 2016, 5, 1; 131-143
2084-5537
2544-1728
Pojawia się w:
Information Systems in Management
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection on broadband signals in the field of aperture and array systems
Autorzy:
Mazurek, R.
Lasota, H.
Budzińska, I.
Powiązania:
https://bibliotekanauki.pl/articles/332465.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustics
broadband signals
array systems
Opis:
Antennas and antenna arrays in low band underwater systems introduce significant linear distortions that affect the detection of broadband signals. The article gives an analysis of the distortions using the space-time impulse response method. The signal received at different directions is subjected to two types of filtration, one matched to the transmitted signal and another one matched to the distorted signal. For the purpose of the simulation the Matlab software was used. Detection performance can be greatly enhanced, if receiver design takes account of the distortions.
Źródło:
Hydroacoustics; 2003, 6; 275-284
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tracking of the broadband source of the underwater noise in the very shallow water conditions
Autorzy:
Grelowska, G.
Kozaczka, E.
Powiązania:
https://bibliotekanauki.pl/articles/331537.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
broadband signals
shallow water
sound propagation
Opis:
The paper contains the results, both theoretical and experimental, connected with the tracking of the underwater noise source as small ships, pontoon, diver and so on. The problem of security in the shallow water area is the challenge for underwater acousticians. In this paper there is taken into account the detection of the sources that move on the surface of the sea or underwater in shallow and very shallow water. The main goal deals with characterization of the sound propagation at the shallow water channel. The next problem is formulation of the sound propagation inside of this acoustic duct including normal mode creations and dispersion of the acoustic energy. When we take into account the small ships noise the two main sources are analyzed. The first one is the vibration energy produced by the mechanisms located inside of the ship hull. The acoustical energy is transformed through structural elements of the hull to surrounding water. This energy propagates as broadband underwater noise. The next source is the ship propeller. The sources of the underwater noise give the some deposit to the total acoustical energy that means the ambient noise. The problem that should be solved is to discover these acoustical disturbances along with their classification, identification and tracking.
Źródło:
Hydroacoustics; 2015, 18; 77-86
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Competition and Diffusion of Telecommunication Services: The Multimedia Communication Services in Brazil
Autorzy:
Rauen, C. V.
Powiązania:
https://bibliotekanauki.pl/articles/307604.pdf
Data publikacji:
2012
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
Brazil
broadband
competition regulation
international experiences
Opis:
This paper aims to discuss the recent trends in the regulation of telecom services regarding the diffusion of broadband. To this matter, it compares the recent international competition regulation experiences to the Brazilian scenario. Considering that the telecom sector passed through huge technological and structural transformations in the last decades (from typical voice communications to convergent services based on broadband, and from voice services monopoly to multiple services oligopoly), its regulatory framework has also changed. Lately, several countries - such as the United States, the Netherlands, Korea and Chile - have established inter and intra-platform competition regulations in order to expand the access to the new forms of communications based on broadband. In Brazil, such mechanisms are not fully explored, and the country has lots of areas in which there is no competition in broadband services (known as multimedia communication services). As a result, Brazil has one of the highest prices of broadband services and one of the lowest levels of broadband penetration. In this way and considering international success in expanding services through competition, the paper defends that such mechanisms should be reinforced in the Brazilian broadband market.
Źródło:
Journal of Telecommunications and Information Technology; 2012, 4; 22-30
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of tonal and broadband hydrodynamic noises of noncavitating underwater propeller
Autorzy:
Kheradmand, S.
Rahrovi, A.
Mousavi, B.
Powiązania:
https://bibliotekanauki.pl/articles/259022.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Numerical Simulation
tonal
broadband
Hydrodynamic Noise
Propeller
Opis:
The objective of the study was to carry out numerical simulation of the hydrodynamic noise generated by the flow around a non-cavitating underwater propeller. To achieve this goal, hydrodynamic simulation of flow around the propeller was initially done. The unsteady 3-D flow was modelled numerically along with the LES turbulence model. The hydrodynamic parameters calculated for different advance coefficients are visibly in line with the previous experimental works. The turbulent quantities of the hydrodynamic study and the FWH model were used to find spectral distributions of flow noise for different advance coefficients. The results of the acoustic investigation were compared against other numerical results. An array of 100 hydrophones was used to find the directional distribution of the noise around the propeller. The obtained results indicate that, for different advance coefficients, the highest intensity of the noise recorded by different receivers around the propeller occurs in BPF. Furthermore, it has been found that the noise is directionally as well as intensively distributed around the propeller. Noise distributions of noise are presented and discussed for different regimes of propeller rotation. The analysis of the expanded spectrum (broadband analysis) of noise on the propellers has also been done and the contribution of all parts of the propeller to hydrodynamic noise generation are presented.
Źródło:
Polish Maritime Research; 2014, 3; 46-53
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Broadband concept of energy harvesting in beam vibrating systems for powering sensors
Autorzy:
Rysak, A
Müller, M.
Borowiec, M.
Zubrzycki, J.
Litak, G.
Godlewska-Lach, A
Wittstock, V.
Powiązania:
https://bibliotekanauki.pl/articles/957989.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
piezoceramic
energy harvesting
vibration
broadband effect
impacts
Opis:
Recent demand for powering small sensors for wireless health monitoring triggered activities in the field of small size efficient energy harvesting devices. We examine energy harvesting in an aluminium beam with a piezoceramic patch subjected to kinematic harmonic excitation and impacts. Due to a mechanical stopper applied, inducing a hardening effect in the spring characteristic of the beam resonator, we observed a broader frequency range for the fairly large power output. Impact nonlinearities caused sensitivity to initial conditions and appearance of multiple solutions. The occurrence of resonant solution associated with impacts increased efficiency of the energy harvesting process.
Źródło:
Advances in Science and Technology. Research Journal; 2014, 8, 23; 62-67
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rozwój sieci szerokopasmowych z wykorzystaniem interfejsów VB5.1 i VB5.2
VB5.1 and VB5.2 interfaces - evolution of broadband networks
Autorzy:
Lutoborski, P.
Powiązania:
https://bibliotekanauki.pl/articles/317420.pdf
Data publikacji:
2001
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
sieci szerokopasmowe
sygnalizacje cyfrowe
broadband networks
digital signalling
Opis:
Scharakteryzowano interfejsy VB5.x, ich niezależność od technologii sieci dostępowych, funkcje zarządzania, integrację dostępów użytkownika i współpracę z różnymi rodzajami węzłów usługowych. Przedstawiono również założenia dotyczące interfejsów VB5.x oraz model funkcjonalny i model odniesienia interfejsów VB5.x.
In this paper basic characteristics of VB5.x broadband interfaces, architecture, tasks, management functions, transport network, and interworking with various service node types were discussed. General VB5.x design principles as well as functional and reference models were given.
Źródło:
Telekomunikacja i Techniki Informacyjne; 2001, 1; 59-67
1640-1549
1899-8933
Pojawia się w:
Telekomunikacja i Techniki Informacyjne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic Models in Techno-Economic Analysis of Broadband Access Networks
Autorzy:
Olender, P.
Powiązania:
https://bibliotekanauki.pl/articles/309138.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
broadband
decision support
FTTH
network planning
stochastic programming
Opis:
Development of networks, specially access networks, is very important and urgent task nowadays. However, it turns out that this segment of telecommunication networks is the most expensive and complicated part of this undertaking. Therefore, the thorough analyses are carried out to determine the best solution under specific circumstances before any decisions are made. This paper presents techno-economic model, which was implemented and used to carry out analyses for one of the biggest city in Poland. To take uncertainty into consideration the stochastic approach was applied providing more robust solution, therefore, improving the safety of investment. Analyses concern FTTH (fibre to the home) technology, type of generic FTTx network architecture. It uses optical fibre in local telecommunication loop, what is becoming more and more popular. Presented results show the usefulness of techno-economic surveys in planning access networks development. The appropriate choice of network parameters, such as the aggregation ratio, is essential and could significantly influence the investment profitability.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 2; 43-51
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A broadband uniplanar quasi-Yagi antenna - parameter study in application to a spatial power combiner
Autorzy:
Białkowski, M.E.
Song, H.J.
Kabacik, P.
Powiązania:
https://bibliotekanauki.pl/articles/309150.pdf
Data publikacji:
2001
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
broadband quasi-Yagi antenna
passive spatial power combiner
Opis:
A parameter study is performed of a broadband uniolanar quasi-Yagi antenna with regard to its design and use in a spatial power combiner. A 3D full-wave electromagnetic field analysis is applied to identify parameters, which mostly affect the design frequency and operational handwidth of this antenna. Optimal design conditions are determined. Using these design criteria a passive spatial power combiner employing trays of back-to-back connected quasi-Yagi antennas is developed. This combiner is investigated in terms of insertion losses and field uniformity, which are key factors in obtaining high power combining efficiency.
Źródło:
Journal of Telecommunications and Information Technology; 2001, 4; 41-47
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Demonstration of a high extinction ratio TiN-based TM-pass waveguide polarizer
Autorzy:
Zhao, Zhuan
Santi, Giovanni
Corso, Alain Jody
Pelizzo, Maria Guglielmina
Powiązania:
https://bibliotekanauki.pl/articles/2172856.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
plasmonic waveguide polarizer
extinction ratio
insertion loss
broadband
Opis:
A high extinction ratio transverse magnetic (TM)-pass plasmonic waveguide polarizer has been designed and optimized. This device exploits two parallel TiN strips embedded in a silicon dioxide cladding to cut off the transverse electric (TE) polarization state, which is either reflected or absorbed, while the TM mode can pass through the main silicon waveguide with significant low losses. Given a device of 5 μm length, an extinction ratio as high as 60.7 dB and an insertion loss of 2.23 dB were achieved at the target wavelength of 1.55 μm. To our knowledge, this extinction ratio is one of the highest values ever reported. In the wavelength of 1.45–1.59 μm, the proposed device provides an optical bandwidth of 140 nm for an extinction ratio more than 30 dB and an insertion loss less than 3 dB. This device is relatively simple and is easier to be fabricated than other architectures that are found in the literature.
Źródło:
Optica Applicata; 2022, 52, 4; 585--598
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Verification of the Theoretical Model of Sound Radiation from an Unflanged Duct with Low Mean Flow
Autorzy:
Gorazd, Ł.
Jurkiewicz, J.
Snakowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/178135.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
convected wave equation
unflanged cylindrical duct
multimodal
broadband excitation
Opis:
The paper deals with experimental verification of results provided by theoretical approach to the problem of sound radiation from an unflanged duct with mean flow of the medium taking into account existence of all allowable wave modes and, in particular, occurrence of the so-called unstable wave, which results in decay of radiation on and in vicinity of the duct axis. The flow is assumed to be uniform with the source of flow located inside the duct, which is the case frequently occurring in industrial systems. Mathematical considerations, accounting for multimodal and multifrequency excitation and diffraction at the duct outlet, are based on the model of the semi-infinite unflanged hard duct with flow. In the experimental set-up a fan, mounted inside the duct served as the source of flow and noise at the same time modelled as an array of uncorrelated sources of broadband noise, what led to the axisymmetrical shape of the sound pressure directivity characteristics. The theoretical analysis was carried out for the root mean square acoustic pressure in the far-field conditions. Experimental results are presented in the form of the measured pressure directivity characteristics obtained for uniform flow directed inwards and outwards the duct compared to this observed for the zero-flow case. The directivity was measured in one-third octave bands throughout five octaves (500 Hz – 16 kHz) which, for a duct with radius of 0.08 m, corresponds to the range 0.74–23.65 in the reduced frequency ka (Helmholtz number) domain. The results obtained are consistent with theoretical solutions presented by Munt and Savkar, according to whom the weakening of the on-axis and close-to-axis radiation should take place in the presence of medium flow. Experimental results of the present paper indicate that this effect is observed even for the Mach number as low as 0.036.
Źródło:
Archives of Acoustics; 2012, 37, 2; 227-236
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Broadband Input Block of Radio Receiver for Software-Defined Radio Devices
Autorzy:
Magnuski, M.
Surma, M.
Wójcik, D.
Powiązania:
https://bibliotekanauki.pl/articles/225973.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
software defined radio
radio receiver
broadband
antenna
tuned filter
Opis:
In the paper a cost-effective input block of the SDR receiver for 0.9 - 2.4GHz frequency band built of capacitivetuned selective amplifier and broadband Vivaldi antenna is presented. The applied selective amplifier consists of three identical sections of tunable filters and two stages of monolithic broadband amplifiers. The single filter section proposed by the authors, due to its ability to absorb parasitic inductances of varicap diodes, simplifies usage of encapsulated varicap diodes in design of tunable in broad band selective filters dedicated to input stages of the receivers. Moreover, proposed filter section has small variation of in-band insertion loss in comparison to varicap-tuned filters built of coupled transmission lines which are commonly applied in input blocks of the microwave receivers. The described selective amplifier could be easily integrated on a single substrate with the Vivaldi antenna which is a cost effective way of fabrication of the tunable in broad band input block of a receiver that has desired gain, selectivity and directivity of the antenna.
Źródło:
International Journal of Electronics and Telecommunications; 2014, 60, 3; 233-238
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of efficiency for broadband unidirectional light scattering by core-shell nanoantennas
Autorzy:
Wang, Weimin
Wang, Xiaoyue
Huang, Biqun
Jing, Xufeng
Li, Chenxia
Powiązania:
https://bibliotekanauki.pl/articles/173186.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
nanoparticles
core-shell nanocube
particle chain
broadband unidirectional scattering
Opis:
A core-shell nanocube antenna is proposed to numerically simulate broadband unidirectional scattering. Comparing the scattering of a dielectric nanocube and core-shell nanocube, it is found that the core-shell nanocube has a higher forward/backward ratio and better unidirectional scattering efficiency. In order to further enhance forward scattering efficiency and reduce the side-lobe of scattering, the particle chain of core-shell nanocubes is proposed by arranging multiple nanoparticles. It is possible to achieve better unidirectional scattering over a wide spectral range. In addition, we also numerically studied the effect of the gap between the particles and the radius of the metal core on unidirectional scattering. It is demonstrated that the optimal gap should be selected to achieve ideal unidirectional forward scattering. The unique optical properties of core-shell nanocubes have important practical applications particularly in the fields of nanoantennas, photovoltaic devices, and nanolasers that require reflection suppression.
Źródło:
Optica Applicata; 2019, 49, 4; 655-667
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
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