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Wyszukujesz frazę "Modulation" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Magnetospectroscopy of CdTe/Cd₁-xMgxTe modulation-doped quantum wells in THz and visible range
Autorzy:
Łusakowski, Jerzy
Zaremba, Maciej
Siemaszko, Adam
Karpierz, Krzysztof
Adamus, Zbigniew
Wojtowicz, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2204169.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
terahertz spectroscopy
optically detected cyclotron resonance
modulation-doped CdTe quantum wells
Opis:
Transport, photoluminescence, THz transmission, and optically detected cyclotron resonance studies were carried out on samples with a single modulation-doped CdTe/Cd1-xMgxTe quantum well. THz experiments were performed at liquid helium temperatures for photon energies between about 0.5 meV and 3.5 meV. An effective mass of electron was determined to be (0.1020 ± 0.0003)m₀. Observed photoluminescence and optically detected cyclotron resonance spectra cannot be explained within the simple model of Landau quantization of parabolic bands.
Źródło:
Opto-Electronics Review; 2023, 31, 2; art. no. e144597
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dimming control schemes combining IEEE 802.15.7 and SC-LPPM modulation schemes with an adaptive M-QAM OFDM for indoor LOS VLC systems
Autorzy:
Mohammed, Nazmi A.
Badawi, Kareem A.
Khalaf, Ashraf A. M.
El-Rabaie, S.
Powiązania:
https://bibliotekanauki.pl/articles/1818236.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
sub-carrier pulse position modulation
lightning topologies
bit error rate
Opis:
The presented work proposes a new dimming control schemes for indoor visible light communication which combines variable pulse-position modulation, colour shift keying as key schemes of IEEE 802.15.7 standard, and sub carrier-pulse-position modulation as a pulse-position modulation variant with orthogonal frequency division multiplexing. These schemes are then compared with traditional merging schemes utilizing pulse-width modulation and multiple pulse-position modulation with m-ary quadrature amplitude modulation OFDM. The proposed schemes are investigated in a typical room with a different lighting layout (i.e., distinctive and uniform lighting layout), followed by an illumination investigation to evaluate the performance of the proposed schemes, especially the enhanced achieved data rates, and to determine their limitations as reliable visible light communication systems that can satisfy both communication and illumination requirements.
Źródło:
Opto-Electronics Review; 2020, 28, 4; 203--212
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Terahertz response of CdTe/Cd1-xMgxTe modulation-doped multiple quantum wells
Autorzy:
Łusakowski, Jerzy
Frączak, Andrzej
Grymuza, Mikołaj
Imos, Eryk
Siemaszko, Adam
Solarska, Wiktoria
Woyciechowska, Aniela
Zaremba, Maciej
Zdunek, Rafał
Karpierz, Krzysztof
Adamus, Zbigniew
Słupiński, Tomasz
Wojtowicz, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2204183.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
terahertz spectroscopy
Shubnikov-de Haas oscillations
modulation-doped multiple CdTe-based quantum wells
Opis:
Terahertz (THz) transmission, photoresistance, and electrical conductivity experiments were carried out at 4.2 K on a sample with modulation-doped CdTe/Cd1-xMgxTe multiple quantum wells. The measurements were carried out as a function of a magnetic field up to 9 T and a radiation frequency between 0.1 and 0.66 THz. A broad minimum in the transmission curve was observed at magnetic fields corresponding to the cyclotron resonance at given THz frequency which was followed at larger fields by an oscillatory signal, periodic in ˉˡ. Shubnikov-de Haas oscillations were observed in magnetoconductivity and in photoresistance. Each of these experimental signals revealed the same electron concentration equal to (1.01 ± 0.03) ∙10ˡ² cmˉ². THz spectroscopy results are compared with data obtained on a single quantum well and are discussed from the point of view of using such multiple quantum wells as THz optical elements.
Źródło:
Opto-Electronics Review; 2023, 31, 2; art. no. e144600
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dimming control schemes combining IEEE 802.15.7 and SC-LPPM modulation schemes with an adaptive M-QAM OFDM for indoor LOS VLC systems
Autorzy:
Mohammed, Nazmi A.
Badawi, Kareem A.
Khalaf, Ashraf A. M.
El-Rabaie, El-Sayed
Powiązania:
https://bibliotekanauki.pl/articles/1818230.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
sub-carrier pulse position modulation
lightning topologies
bit error rate
Opis:
The presented work proposes a new dimming control schemes for indoor visible light communication which combines variable pulse-position modulation, colour shift keying as key schemes of IEEE 802.15.7 standard, and sub carrier-pulse-position modulation as a pulse-position modulation variant with orthogonal frequency division multiplexing. These schemes are then compared with traditional merging schemes utilizing pulse-width modulation and multiple pulse-position modulation with m-ary quadrature amplitude modulation OFDM. The proposed schemes are investigated in a typical room with a different lighting layout (i.e., distinctive and uniform lighting layout), followed by an illumination investigation to evaluate the performance of the proposed schemes, especially the enhanced achieved data rates, and to determine their limitations as reliable visible light communication systems that can satisfy both communication and illumination requirements.
Źródło:
Opto-Electronics Review; 2020, 28, 4; 203--212
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discussion around IR material and structure issues to go toward high performance small pixel pitch IR HOT FPAs
Autorzy:
Gravrand, Olivier
Baier, Nicolas
Ferron, Alexandre
Rochette, Florent
Lobre, Clément
Bertoz, Jocelyn
Rubaldo, Laurent
Powiązania:
https://bibliotekanauki.pl/articles/2204207.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
mid-wave infrared
focal plane array
high operating temperature
small pitch
modulation transfer function
finite element method
Opis:
In the last decade, infrared imaging detectors trend has gone for smaller pixels and larger formats. Most of the time, this scaling is carried out at a given total sensitive area for a single focal plane array. As an example, QVGA 30 μm pitch and VGA 15 μm pitch exhibit exactly the same sensitive area. SXGA 10 μm pitch tends to be very similar, as well. This increase in format is beneficial to image resolution. However, this scaling to even smaller pixels raises questions because the pixel size becomes similar to the IR wavelength, but also to the typical transport dimensions in the absorbing material. Hence, maintaining resolution for such small pixel pitches requires a good control of the modulation transfer function and quantum efficiency of the array, while reducing the pixel size. This might not be obtained just by scaling the pixel dimensions. As an example, bulk planar structures suffer from excessive lateral diffusion length inducing pixel-to-pixel cross talk and thus degrading the modulation transfer function. Transport anisotropy in some type II superlattice structures might also be an issue for the diffusion modulation transfer function. On the other side, mesa structures might minimize cross talk by physically separating pixels, but also tend to degrade the quantum efficiency due to a non-negligible pixel fill factor shrinking down the pixel size. This paper discusses those issues, taking into account different material systems and structures, in the perspective of the expected future pixel pitch infrared focal plane arrays.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144561
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of hybrid PDM-4QAM-OFDM for inter-satellite/mechatronic telecommunication using FSO system
Autorzy:
Singh, Shivmanmeet
Grewal, Narwant Singh
Kaur, Baljeet
Powiązania:
https://bibliotekanauki.pl/articles/27315699.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
inter-satellite optical wireless communication
IsOWC
mechatronic telecommunication
polarisation division multiplexing-quadrature amplitude modulation-orthogonal frequency division multiplexing
PDM-4QAM-OFDM
Opis:
In this paper, the designing and simulation of 400 Gbps polarisation division multiplexingquadrature amplitude modulation-orthogonal frequency division multiplexing (PDM- 4QAM-OFDM)-based inter-satellite optical wireless communication (IsOWC)/mechatronic telecommunication system for improving the link information carrying capacity was carried out. With quadrature amplitude modulation (QAM) encoding, the performance of the executed system has been addressed using metrics such as signal to noise ratio (SNR) and total received power (RP). The performance with suggested system has been examined in relation to the effects of various factors such as operating wavelength, transmission power, and receiving pointing error angle. Moreover, a better identification method for improving connection reach between mechatronic devices/satellites has been revealed in this study. A performance comparison of the proposed system with other implemented approaches has been made in the final step.
Źródło:
Opto-Electronics Review; 2023, 31, 3; art. no. e147036
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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