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Tytuł:
Herbowe ekslibrisy L. S. J. barona Schimmelpfenninga : domniemane znaki książkowe Biblioteki Rady Miejskiej Poznania z XVI-XVII wieku
Die Wappenexlibris von Baron L. S. J. Schimmelpfennig - angebliche Bucheignerzeichen der Posener Stadtratsbibliothek aus dem 16.-17. Jahrhundert
Autorzy:
Wagner, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/1041030.pdf
Data publikacji:
2002
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II
Tematy:
Heraldik
Geschichte
16.-17. Jahrhundert
Wappen
Holzschnitt
heraldyka
historia
XVI-XVII wiek
herb
drzeworyt
heraldry
history
16th-17th century
crest
woodcat
Opis:
Der Artikel ist einem heraldischen Exlibris gewidmet, das in der polnischen Fachliteratur bisher als Buchzeichen der Posener Stadtratsbibliothek aus dem 16.-17. Jahrhundert fungiert. Es wurde in Linolschnittechnik ausgeführt und stellt einen Schild mit Wappenbild, Helm und von zwei Löwen gehaltenem Kleinod dar. Die Gesamtkomposition befindet sich in einer Umrandung aus Lorbeerblättern. In Wirklichkeit gehörte das Exlibris, wie eine genaue künstlerisch-heraldische Analyse ergab, Baron Ludwig Simon Juda Schimmelpfennig (de Schimmelpennink van der Oye, 1708-1772), einem privaten Buchliebhaber aus dem Ermland, Domherr in Dobre Miasto (Guttstadt), Pfarrer in Kiwity, Ryna Reszelska (bei Rössel) und Rogóż. Seine Bibliothek bestand vorwiegend aus Werken mit religiöser Thematik, die er dem Jesuitenkloster in Swieta Lipka (Heiligenlinde) testamentarisch vermachte. Nach dem Krieg gelangte sie zusammen mit den aus diesem Kloster stammenden Frühdrucken in die Bibliothek des Bobolanum in Warschau, wo sie sich bis heute befindet. Die Untersuchung dieser Büchersammlung ergab, daß noch zwei weitere, in der Literatur unbekannte Exlibris von Schimmelpfennig existieren. Eines davon bildet eine Variante des aus der Literatur bekannten Exlibris (mit ihm ist die überwiegende Mehrheit der Bücher beklebt), das zweite dagegen basiert, obwohl es ebenfalls das Wappen des Besitzers darstellt, auf einer anderen Komposition und stammt höchstwahrscheinlich von einem anderen Künstler. Alle diese Exlibris sind höchstwahrscheinlich nach der Mitte des 18. Jahrhunderts entstanden, wovon die Eigentumsvermerke des Sammlers zeugen. Diese Vermerke gibt es in zwei Ausführungen: die die Personalien und ein Verzeichnis der kirchlichen Funktionen des Sammlers enthaltenden Identifikationsvermerke (welche wahrscheinlich vom Besitzer selbst stammen) und die sich auf sein Legat beziehenden Memorativvermerke (welche von anderer Hand stammen). Sie befinden sich in den Büchern meistens zusammen mit dem Exlibris (dann auf dem Vordersatz), viel seltener auf einem anderen Blatt oder selbständig - ohne Exlibris.
Źródło:
Archiwa, Biblioteki i Muzea Kościelne; 2002, 77; 443-463
0518-3766
2545-3491
Pojawia się w:
Archiwa, Biblioteki i Muzea Kościelne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the biotope quality unfavourable to ichthyofauna of the Szczecin Lagoon during the flood crest outflow in summer 1997
Niekorzystne dla ichtiofauny zmiany jakości biotopu toni wodnej Zalewu Szczecińskiego podczas spływu wód powodziowych latem 1997 roku
Autorzy:
Poleszczuk, G.
Powiązania:
https://bibliotekanauki.pl/articles/85133.pdf
Data publikacji:
2003
Wydawca:
Akademia Pomorska w Słupsku
Tematy:
biotope change
biotope quality
water quality
Odra estuary
fish
ichthyofauna
Szczecin Lagoon
flood crest outflow
summer
fish habitat
Źródło:
Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline; 2003, 06
1643-0115
Pojawia się w:
Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DAC testing using modulated signals
Autorzy:
Fexa, P.
Verdal, J.
Svatoš, J.
Powiązania:
https://bibliotekanauki.pl/articles/220431.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
digital-to-analog converter
ENOB
Signal-to-noise and distortion - SINAD
FFT analysis
Crest Factor (CF)
Opis:
This document analyses qualities of methods used for testing dynamical parameters of Digital-to-Analog Converters (DAC) using a multi-frequency signal. As the source for these signals, Amplitude Modulated (AM) and Frequency Modulated (FM) signals are used. These signals are often used in radio engineering. Results of the tests, like Effective Number of Bits (ENOB), Signal-to-Noise and Distortion (SINAD), are evaluated in the frequency domain and they are compared with standard results of Sine Wave FFT test methods. The aim of this research is firstly to test whether it is possible to test a DAC using modulated signals, secondly to reduce testing time, while estimating band performance of DAC.
Źródło:
Metrology and Measurement Systems; 2011, 18, 2; 283-293
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expression of cellular retinoic acid-binding protein I and II (CRABP I and II) in embryonic mouse hearts treated with retinoic acid
Autorzy:
Stachurska, Emilia
Loboda, Agnieszka
Niderla-Bielińska, Justyna
Szperl, Małgorzata
Juszyński, Michał
Jozkowicz, Alicja
Dulak, Jozef
Ratajska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/1039942.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
CRABP I
embryonic mouse heart
CRABP II
retinoic acid
neural crest
Opis:
Cellular retinoic acid binding proteins are considered to be involved in retinoic acid (RA) signaling pathways. Our aim was to compare the expression and localization of cellular retinoic acid binding proteins I and II (CRABP I and II) in embryonic mouse hearts during normal development and after a single teratogenic dose of RA. Techniques such as real-time PCR, RT-PCR, Western blots and immunostaining were employed to examine hearts from embryos at 9-17 dpc. RA treatment at 8.5dpc affects production of CRABP I and II in the heart in the 48-h period. Changes in expression of mRNA for retinaldehyde dehydrogenase II (Raldh2), Crabp1 and Crabp2 genes also occur within the same time window (i.e. 10-11dpc) after RA treatment. In the embryonic control heart these proteins are localized in groups of cells within the outflow tract (OT), and the atrioventricular endocardial cushions. A gradient of labeling is observed with CRABP II but not for CRABP I along the myocardium of the looped heart at 11 dpc; this gradient is abolished in hearts treated with RA, whereas an increase of RALDH2 staining has been observed at 10 dpc in RA-treated hearts. Some populations of endocardial endothelial cells were intensively stained with anti-CRABP II whereas CRABP I was negative in these structures. These results suggest that CRABP I and II are independently regulated during heart development, playing different roles in RA signaling, essential for early remodeling of the heart tube and alignment of the great arteries to their respective ventricles.
Źródło:
Acta Biochimica Polonica; 2011, 58, 1; 19-29
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DAC testing using impulse signals
Autorzy:
Vedral, J.
Fexa, P.
Powiązania:
https://bibliotekanauki.pl/articles/221597.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DAC
ENOB
SINAD
FFT test
Crest Factor
Damped Sine Wave
SINC signal
Multi-Tone signal
Opis:
The Multi-Tone (MT) signal with uniform amplitudes can be used for DAC testing. This paper shows an easier way to generate a MT signal using several impulse signals. The article also analyzes qualities of methods for testing the dynamic parameters of Digital to Analog Converters using an impulse signal. The MT, Damped Sine Wave (DSW) and Sinx/x (SINC) signals will be used as the source for these tests. The Effective Number of Bits (ENOB) and Signal to noise and distortion (SINAD) are evaluated in the frequency domain and they are modified using the Crest Factor (CF) correction and compared with the standard results of the Sine Wave FFT test. The first advantage of the test using an impulse signal is that you need fewer input parameters to create the band signal for testing the DAC. The second one is to reduce the testing time using a band signal in comparison with multiple tests using a single sine wave.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 105-114
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardware Accelerated Simulation of Crest Factor Reduction Block for Mobile Telecommunications
Autorzy:
Nikodem, M.
Kępa, K.
Powiązania:
https://bibliotekanauki.pl/articles/226366.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
crest factor reduction
configurable hardware
hardware acceleration
FPGA
telecommunications
Opis:
This paper reports results of the hardware accelerated simulations of the crest factor reduction (CFR) block which is a common element of the radio signal processing path in base stations for mobile telecommunications. Presented approach increases productivity of radio system architects by shortening the time of model architecture evaluation. This enables unprecedented scale of CFR parameter optimization which requires thousands of simulation runs. We use FPGA device and Xilinx System Generator for DSP technology in order to model CFR block in MATLAB/Simulink environment, implement the accelerator and use it for mixed hardware-software simulation. Reported approach reduces simulation time by 70%, provides straight forward use of fixed-point arithmetic and lowers power consumption by 73% at the cost of constant and relatively low overhead on model development.
Źródło:
International Journal of Electronics and Telecommunications; 2012, 58, 4; 363-368
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Justification of permissible wear parameters of locomotives crest wheel
Obosnovanie predelno-golustimykh parametrov iznosa grebnejj koles lokomotivov
Autorzy:
Sapronova, S.
Tkachenko, V.
Powiązania:
https://bibliotekanauki.pl/articles/792578.pdf
Data publikacji:
2013
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
railway
locomotive wheel
tire
wheel profile
justification
wear parameter
permissible value
economic performance
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2013, 13, 4
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Cretaceous crest-bearing shrimps from the Sahel Alma Lagerstatte of Lebanon
Autorzy:
Audo, D.
Charbonnier, S.
Powiązania:
https://bibliotekanauki.pl/articles/20885.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Late Cretaceous
crest-bearing shrimp
Arthropoda
Crustacea
Decapoda
Lagerstatte
Cretaceous
Santonian
Sahel Alma
Lebanon
Opis:
Decapod crustaceans are the most diverse group of fossil invertebrates from the Upper Cretaceous Sahel Alma Lagerstätte (Lebanon, Middle East). They are mainly represented by abundant crest−bearing shrimps which were first described as Penaeus libanensis. We review this species applying the new systematic nomenclature and we propose a more complete description based on 54 unpublished specimens. This review leads to the erection of Palaeobenthesicymus gen. nov. and to the new combination Palaeobenthesicymus libanensis that is the oldest record of the family Benthesicymidae. A neotype is herein designated. Detailed comparisons with extant analogues suggest that the crest bearing shrimps inhabited relatively deep water settings most probably exceeding 150 m, at the transition between the lower circalittoral and the upper bathyal zones, under dysphotic or aphotic conditions.
Źródło:
Acta Palaeontologica Polonica; 2013, 58, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uwagi o znakach własnościowych z drugiej połowy XV i pierwszej ćwierci XVI wieku w inkunabułach Biblioteki Uniwersyteckiej w Poznaniu
Some remarks on the private marks of ownership of books from the latter half of the fifteenth century and the first decades of the sixteenth century in the incunabula kept at Poznań University Library
Autorzy:
Wagner, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/910764.pdf
Data publikacji:
2013-01-01
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
painted bookplate
clasp book plate – Schließen-Exlibris
crest
ekslibris malowany
superekslibris
zapięciowy – Schließen-Exlibris
herb
Piotr Wedelicjusz z Obornik
prymas Stanisław Karnkowski
Anonim „L G” herbu Rawicz
Opis:
Artykuł stanowi Zbiór uwag dotyczących charakterystycznych kategorii Dodaj znakow własnościowych książki, znajdujących Się w inkunabułach ZE Zbiorów Biblioteki Uniwersyteckiej w Poznaniu, osadzonych na TLE zjawisk kulturowych późnego średniowiecza i początków renesansu w Europie IW Polsce. Analizie zostały poddane: ekslibris malowany (protoekslibris), rysunkowy wzór ołtarza herbem fundatora wklejony oo nie Książki Jako Przedmiot dewocji í prawdopodobnie znak Własności, TZW. superekslibris zapięciowy umieszczony na zaczepie zapięcia oprawy, nazwiska właścicieli ksiąg zapisane na okładzinach opraw, herby rysowane na stronach tytułowych. Osobną uwagę poświęcono ekslibrisom graficznym, w Tym zwłaszcza unikatowym dziełom związanym z anonimowym bibliofilem herbu Rawicz, Oraz ekslibrisom odbijanym bezpośrednio na kartach ksiąg.
This article reports on a set of remarks on the characteristic types of private ownership marks that are to be fund in the incunabula currently held in the collection of old and rare books at Poznań University Library. The marks of ownership are analyzed and positioned against the cultural phenomena of the late Middle Ages and early decades of Renaissance in Europe and Poland. First, the hand-painted bookplate (the earliest form of book plates) is discussed. This analysis is then followed by descriptions of the sketched altar model (bookplate depicting an altar) with the coat-of-arms of the donator pasted into a book as an object of devotion and, presumably, a proper mark of ownership, then the so-called clasp hasp bookplate (in German language: Schließen-Exlibris), placed on the hasp of the clasp on the binding. Finally, names inscribed on the inside front cover of a book that indicated its owner or owners, and individual family crests placed on title pages are discussed. Separate attention is given to graphical bookplates, in particular to unique pieces of ornamentation that relate to the anonymous book collector with the exhibited noble Rawicz coat of arms, as well as to book plates imprinted directly onto pages of books.
Źródło:
Biblioteka; 2013, 17(26); 7-35
1506-3615
2391-5838
Pojawia się w:
Biblioteka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Apoteoza godła heraldycznego biskupa Macieja Grzegorza Garnysza w łacińskich wierszach herbowych w rubrycelach diecezji chełmskiej
The apotheosis of Bishop Maciej Grzegorz Garnysz’s family crest in Latin poems in the directories of the Chełm Diocese
Autorzy:
Marczewski, Jarosław R.
Strycharczuk, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/1022715.pdf
Data publikacji:
2015-12-16
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II
Tematy:
biskup chełmski Maciej Grzegorz Garnysz
diecezja chełmska
rubrycele
herb
poezja herbowa
Bishop of Chełm Maciej Grzegorz Garnysz
the Diocese of Chełm
directories
family crest
family crest poetry
Opis:
Directories play an important role in pastoral life of every diocese. In Poland, the first known prints of this type come from the sixteenth century. They include liturgical calendar with the local celebrations, pastoral directives, a list of institutions and clergy working in the diocese. Directories are issued by the authority of the bishop. In the past, publishing them provided the opportunity to print bishop’s family crest and an appropriate Latin poem on the first page. From the period of the rule of the Bishop of Chełm Maciej Grzegorz Garnysz († 1790) there remained 4 directories exposing the Garnysz family crest - Poraj. The  authors of the poems included in the above-mentioned prints are unknown. These poems are in the form of epigrams. In terms of the composition, they are short lyric poems with four- and six-line stanzas, written in elegiac couplet. In this article, they were reprinted and translated into Polish. Their analysis and translation are completely new phenomena, as in Poland there are no other works presenting translation or a study of the poems included in directories.
Źródło:
Archiwa, Biblioteki i Muzea Kościelne; 2015, 104; 167-187
0518-3766
2545-3491
Pojawia się w:
Archiwa, Biblioteki i Muzea Kościelne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bearing estimation using double frequency reassignment for a linear passive array
Autorzy:
Czarnecki, K.
Leśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/260131.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
direction of arrival
DOA
instantaneous frequency
short-time Fourier transform
STFT
time-frequency reassignment
intercept and surveillance sonar
crest factor
Opis:
The paper demonstrates the use of frequency reassignment for bearing estimation. For this task, signals derived from a linear equispaced passive array are used. The presented method makes use of Fourier transformation based spatial spectrum estimation. It is further developed through the application of two-dimensional reassignment, which leads to obtaining highly concentrated energy distributions in the joint frequency-angle domain and sharp graphical imaging. The introduced method can be used for analysing, a priori, unknown signals of broadband, nonstationary, and/or multicomponent type. For such signals, the direction of arrival is obtained based upon the marginal energy distribution in the angle domain, through searching for arguments of its maxima. In the paper, bearing estimation of three popular types of sonar pulses, including linear and hyperbolic frequency modulated pulses, as well as no frequency modulation at all, is considered. The results of numerical experiments performed in the presence of additive white Gaussian noise are presented and compared to conventional digital sum-delay beamforming performed in the time domain. The root-mean-square error and the peak-to-average power ratio, also known as the crest factor, are introduced in order to estimate, respectively, the accuracy of the methods and the sharpness of the obtained energy distributions in the angle domain.
Źródło:
Polish Maritime Research; 2017, 3; 26-35
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental Flood Protection Dikes
Autorzy:
Ganiron Jr., Tomas U.
Powiązania:
https://bibliotekanauki.pl/articles/1113827.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Backwater
dike
dike crest
expressway dike
flood
flood level
freeboard
lakeshore
landslide
seepage
Opis:
Flooding is a natural event that replenishes the groundwater and revitalizes the soil through the deposit of sediments. However, when communities settle within floodplains, flooding can cause adverse social, economic and environmental impacts. Flood protection works, such as dikes, can further reduce flood risk. These structures particularly relevant in protecting historic communities that were settled before floodplain management policies were implemented. However, it is technically and economically impossible to completely eliminate flood risk with dikes. During severe floods, dike failures may occur due to erosion, overtopping or seepage. This study predicts that dike construction may lead to water level lowering for in-bank flows and to water level increases for out-of-bank (flood) flows. This confirms that, in principle, the existing Pampanga dike and specifically on the construction of Taguig City dike along the Laguna Lake may have contributed to the observed flood water level trends in the Metro Manila.
Źródło:
World News of Natural Sciences; 2017, 13; 82-100
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raz jeszcze o pieczęci wielkiej miasta Sandomierza
Autorzy:
Stróżyk, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/608153.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Historii im. Tadeusza Manteuffla PAN w Warszawie
Tematy:
sfragistyka
typariusz
pieczęć miejska
heraldyka
herb Orzeł Biały
klejnot herbowy
Wacław II
Władysław Łokietek
Kazimierz Wielki
sigillography
matrix
municipal seal
heraldry
White Eagle
crest
Wenceslaus II
Władysław the Short
Opis:
Artykuł przedstawia krytyczne rozważania nad pieczęcią wielką miasta Sandomierza. Przyjąć należy, że zachowany do dziś typariusz powstał w latach 1297-1300 (może: 1292-1300), a w latach 1320-1343 został przerobiony. 
The paper presents critical considerations about the great seal of the city of Sandomierz. The conclusion is that the preserved matrix was made in 1297-1300 (maybe 1292-1300), and was redesigned during the years 1320-1343.
Źródło:
Roczniki Historyczne; 2017, 83
0324-8585
Pojawia się w:
Roczniki Historyczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gait changes in patients after reconstruction of facial bones with fibula and iliac crest free vascularized flaps
Autorzy:
Syczewska, M.
Krajewski, R.
Szczerbik, E.
Kalinowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/949745.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wzorzec chodu
chirurgia rekonstrukcyjna
nowotwór złośliwy
jama ustna
gait pattern
reconstructive surgery
malignant tumour
oral cavity
Opis:
Patients with malignant tumours of the oral cavity require its surgical removal and reconstruction of the bone and soft tissues. The grafts are obtained either from leg (fibula) or pelvis (iliac crest). The removal of grafts from the locomotor apparatus can impair the gait. The aim of this study was to find out how the localization of donor site influences the gait pattern. Methods: Results obtained for 30 patients were analyzed (16 fibula graft, 14 iliac crest graft). Patients underwent instrumented gait analyses three times (VICON system): before surgery, 2–4 month after the surgery, and 4–8 months after the surgery. Results: In both groups several gait parameters were changed. Two parameters changed in both groups: gait speed and cadence. In patients receiving iliac crest graft the changed gait variables were: pelvic rotation, hip range in sagittal plane (operated side), knee range in sagittal plane (operated side), foot dorsiflexion in swing on both sides. In patients receiving fibula flap the changed gait variables were: tilt, range motion of the tilt, minimum hip flexion (operated side), time to maximum knee flexion (non-operated side), GGI (non-operated side) and step length (nonoperated side). Conclusions: The primary gait deviations occurring after surgery, and the compensatory mechanisms which subsequently arise depend on the localization of graft donor site. The results indicate that the patients in whom fibula flap was used have less problems with gait pattern after the surgery than the patients receiving iliac crest graft.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 1; 185-190
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Suitable Spreading Sequences for Asynchronous MC-CDMA Systems
Autorzy:
Addad, M.
Djebbari, A.
Powiązania:
https://bibliotekanauki.pl/articles/307793.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
BER
crest factor
multiple access interference
MC-CDMA
peak-to-average power ratio
zero correlation zone
Opis:
In order to meet the demand of high data rate transmission with good quality maintained, the multi-carrier code division multiple access (MC-CDMA) technology is considered for the next generation wireless communication systems. However, their high crest factor (CF) is one of the major drawbacks of multi-carrier transmission systems. Thus, CF reduction is one of the most important research areas in MC-CDMA systems. In addition, asynchronous MC-CDMA suffers from the effect of multiple access interference (MAI), caused by all users active in the system. Degradation of the system’s bit error rate (BER) caused by MAI must be taken into consideration as well. The aim of this paper is to provide a comparative study on the enhancement of performance of an MC-CDMA system. The spreading sequences used in CDMA play an important role in CF and interference reduction. Hence, spreading sequences should be selected to simultaneously ensure low CF and low BER values. Therefore, the effect that correlation properties of sequences exert on CF values is investigated in this study. Furthermore, a numerical BER evaluation, as a function of the signal-to-noise ratio (SNR) and the number of users, is provided. The results obtained indicate that a trade-off between the two criteria is necessary to ensure good performance. It was concluded that zero correlation zone (ZCZ) sequences are the most suitable spreading sequences as far as the satisfaction of the above criteria is concerned.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 3; 9-13
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 23

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