Temat: HPA - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: FPGA Adaptive Predistorter Based on 64QAM Modulation
Autorzy:: Pochmara, J.
Katarzyński, P.
Powiązania:: https://bibliotekanauki.pl/articles/226685.pdf
Data publikacji:: 2010
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: digital predistortion
HPA
FPGA
RF systems
Opis:: This paper presents a predistortion technique compensating for nonlinear distortions caused by HPA (High Power Amplifier) in a QAM (Multilevel Quadrature Modulation) system. Investigations were held both with software and hardware tools. It is confirmed by computer simulation that proposed approach produces a faster convergence speed than traditional computer performed algorithms. Predistortion technique based on programmable logic device is a very attractive from the implementation point of view, because of a low amount of required RAM and rapid convergence from a blind start.
Źródło:: International Journal of Electronics and Telecommunications; 2010, 56, 4; 387-392
2300-1933
Pojawia się w:: International Journal of Electronics and Telecommunications
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Enhancement of Power Efficiency in OFDM System by SLM with Predistortion Technique
Autorzy:: Sharma, P. K.
Nagaria, R. K.
Sharma, T. N.
Powiązania:: https://bibliotekanauki.pl/articles/308396.pdf
Data publikacji:: 2011
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: nonlinear HPA
OFDM
PAPR
SLM
Opis:: Orthogonal Frequency Division Multiplexing (OFDM) is considered as a strong candidate for future wireless communication because it is marked by its higher frequency multiplicity and greater immunity to multipath fading. However, the main drawback of OFDM is its high amplitude fluctuations measured by peak-to-average power ratio (PAPR), which leads to power inefficiency and requires expensive high power amplifier (HPA) with very good linearity. In this paper, we propose selected mapping (SLM) with predistortion technique to decrease the nonlinear distortion and to improve the power efficiency of the nonlinear HPA. In the proposed method SLM reduces the PAPR and improves the power efficiency, the predistorter improves the bit error rate (BER) performance of the system. The PAPR reduction is possible with SLM when compared with original OFDM. After reducing the PAPR with SLM the data goes into the HPA with and without predistorter. The BER performance curves of SLM method with or without predistorter shows that, predistorter operates more effectively in SLM method than original OFDM system. At 4 dB IBO (input backoff) the conventional method with predistorter achieves 1.8 dB SNR gain than conventional method without a predistorter and at 6 dB IBO the BER performance is towards the ideal linear amplifier. The proposed system will be evaluated for OFDM system in the presence of a nonlinear power amplifier.
Źródło:: Journal of Telecommunications and Information Technology; 2011, 4; 86-91
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The effects of 1-methylnaphthalene after inhalation exposure on the serum corticosterone levels in rats
Autorzy:: Świercz, Radosław
Stępnik, Maciej
Powiązania:: https://bibliotekanauki.pl/articles/2116549.pdf
Data publikacji:: 2020-09-17
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:: rat
corticosterone
HPA
inhalation exposure
1-methylnaphthalene
restraining stress
Opis:: ObjectivesThis paper reports on the trend of the stressogenic stimulus caused by a repeated exposure to 1-methylnaphthalene (1-MN) vapors at the nominal concentrations of 0 mg/m3 (the control restrainer), 50 mg/m3 or 200 mg/m3 in the nose-only inhalation system, by analyzing the serum corticosterone (CORT) levels in rats.Material and MethodsThree groups of rats were exposed in restrainers to 1-MN vapors at the nominal concentrations of 0 mg/m3, 50 mg/m3 or 200 mg/m3 for 5 days. One control group of animals spent all the time during the experiment in an individually ventilated plastic cage. The serum CORT concentrations were determined in all 4 groups of the rats. The blood samples drawn from the tail vein were collected every day after termination of the 6-h exposure. On the fifth day, blood samples were collected 15 min, 30 min, 45 min, 1 h, and 3 h after termination of the 6-h exposure.ResultsOn the fifth day of the study, no statistically significant changes in body weights between all groups of animals were found. After 5 days of the observation, increased food intake in the control groups was noted. Significantly higher CORT concentrations in the rats exposed to 1-MN at 200 mg/m3 and in the animals from the control restrainer were found, comparing to the animals exposed to 1-MN at 50 mg/m3 and the animals from the control cage.ConclusionsThe application of 6-h restraining induced high concentrations of the stress hormone, CORT, in the blood of rats. The short-term exposure of rats to 1-MN non-linearly reduced the restraint stress measured with CORT concentration.
Źródło:: International Journal of Occupational Medicine and Environmental Health; 2020, 33, 5; 691-699
1232-1087
1896-494X
Pojawia się w:: International Journal of Occupational Medicine and Environmental Health
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A Scientific Inquiry: Galen’s Optics in Dreams of Vision, Light & Pre-Natal Memory
Autorzy:: Gardiner, Judy B.
Powiązania:: https://bibliotekanauki.pl/articles/545523.pdf
Data publikacji:: 2015
Wydawca:: Uniwersytet Gdański. Wydział Filologiczny
Tematy:: Dreaming
Amygdala
Brain
Light
Cognitive/Sensory Processing
Consciousness
Claudius Galen
HPA Axis
Intuition-Instinct-Insight
Memory
Neuroanatomy
Optic Disc
Optogenetics
Optic Nerve
Soul
Synapse
Third Ventricle
Universal Mind
Visual Cortex
Opis:: The following inquiry is derived from a 1994 experiential study in dreaming consciousness in which a series of thirty-eight interlocking dreams revealed Claudius Galen’s (c130-201) pneumatic doctrine of vision. The research centers on the relationship of light in the brain to vision and memory. The objective is to contribute to the understanding of consciousness by elucidating learning-related patterns of neural activity guided by associative recognition in dream-wake states. Scientific breakthroughs introducing photons of light to control brain activity strengthened the findings. Premises stemming from neuroscientific and spiritual insights: *Activation of light in the optic disc may open the visual field to access pre-natal memory. *A unified sixth sense merging Intuition-Insight-Instinct may have its locus in the infundibular recess of the third ventricle. *Memory matrix in the amygdala relays information to the sixth sense thereby serving all sense organs.
Źródło:: Jednak Książki. Gdańskie Czasopismo Humanistyczne; 2015, 4; 191-212
2353-4699
Pojawia się w:: Jednak Książki. Gdańskie Czasopismo Humanistyczne
Dostawca treści:: Biblioteka Nauki

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