Delay Signal
Mostrando 1-12 de 157 artigos, teses e dissertações.
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1. Evaluation of OFDM Channel Sounding Techniques with Three Modulation Sequences
Abstract This paper presents an evaluation of multicarrier channel sounding techniques using different random and pseudo-random sequences to modulate the OFDM sounding signal. The Random (Rand), Pseudo-Noise (PN) and Zadoff-Chu (ZC) were tested, both in laboratory simulations and in field measurements. For the laboratory simulations Matlab routines were used
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 11/11/2019
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2. KLOBUCHAR AND NEQUICK G IONOSPHERIC MODELS COMPARISON FOR MULTI-GNSS SINGLE-FREQUENCY CODE POINT POSITIONING IN THE BRAZILIAN REGION
Abstract One of the main error sources in GNSS positioning comes from the ionosphere, an atmospheric layer that stays in the signal path between the satellite and the receiver. For single frequency positioning, the ionospheric effects can be minimized by using an ionospheric model e.g. Klobuchar or NeQuick G. These models are respectively associated to GPS a
Bol. Ciênc. Geod.. Publicado em: 14/10/2019
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3. Influence of Vegetation on the Outdoor-to-Indoor Mobile Radio Propagation in 700 MHz Band
Abstract Starting from outdoor transmission, crossing vegetation, the wideband and narrowband characterization of the indoor mobile radio channel in the 700 MHz band is obtained from experiments carried out in the indoor environment of the Engineering building at Fluminense Federal University, and from the processed data, respectively, the power-delay profil
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 12/09/2019
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4. ANALYTICAL COMPARISON OF THE PERFORMANCE OF ADAPTIVE MODULATION AND CODING IN WIRELESS NETWORK UNDER RAYLEIGH FADING
Abstract In this paper, an analytic comparison between adaptive modulation (AdM) and adaptive Forward Error Correction (AdFEC) in wireless network telecommunication systems is performed. Through the Gilbert-Elliott model's, the Packet Error Rate (PER) is calculated and both the throughput and the delay, for different modulations and error correction capacity
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-09
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5. Adaptive Wideband Beamforming Based on Digital Delay Filter
Abstract A novel adaptive wideband beamforming method is proposed, where beamforming is achieved by LMS based space-time adaptive filtering algorithm. Conventional broadband beamforming requires desired signal to be incident from the broadside i.e. direction normal to the array. The new method overcome this constraint by make use of digital delay filters whi
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-09
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6. First serine protease inhibitor isolated from Rhinella schneideri poison
Background Toad secretions are a source of molecules with potential biotechnological application on a wide spectrum of diseases. Toads from theRhinella family have two kinds of poisonous glands, namely granular and mucous glands. Rhinella schneideritoads produce granular secretions that comprise a great number of molecules, including serine proteases inhibit
J. Venom. Anim. Toxins incl. Trop. Dis. Publicado em: 29/09/2015
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7. Channel characterization in the 5.8GHz band in a suburban area
Based on signal measurements carried out in the 5.8 GHz band, which is reserved for unlicensed WiMAX in Brazil, this paper evaluates narrowband and wideband characteristics on the suburban area of Tanguá city in Rio de Janeiro State. Fading statistics, coverage and adjusted prediction model such as Hata-COST 231, SUI and UFPA were used in order to find the
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-06
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8. All-optical cryptography through spectral amplitude and delay encoding
All-optical data encryption is a promising technology that could lead communication systems to an unprecedented degree of security. In this paper we use computer simulations to systematically investigate a new all-optical cryptography technique that is bit-rate independent and transparent to modulation formats. Encryption encompasses signal spectral slicing
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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9. SFN channel measurements in Brazil
In this paper, field measurements carried out in a suburban SFN network with two synchronized transmitters are reported. It is found that the radio signal coverage of the distributed transmission scheme is distinctly improved when compared to a single transmitter system. The path loss gain and improvement associated to the SFN scheme are obtained as well as
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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10. Comparison between OFDM and STDCC mobile channel sounders at 3.5 GHz
In this paper, we present a comparison between OFDM and STDCC sounding techniques used to wide band channel characterization in suburban environments at 3.5 GHz band. Measurements of the received signal's power delay profile and power level for each of the sounding techniques were obtained. These experimental results are presented and compared. For this comp
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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11. New strategies for planning and performance evaluation of wireless networks: case studies based on the cross-layer approach
The use of wireless local area networks, called WLANs, as well as the proliferation of the use of multimedia applications have grown rapidly in recent years. Some factors affect the quality of service (QoS) received by the user and interference is one of them. This work presents strategies for planning and performance evaluation through an empirical study of
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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12. Optical cryptography through analog control of amplitude and delay of spectral slices: anlysis for NRZ and DQPSK signals. / Criptografia Ãptica mediante controle analÃgico da amplitude e do atraso de fatias espectrais: anÃlise para sinais NRZ e DQPSK.
This work investigates a technique to encrypt the optical signal for Transparent Optical Network, TON, in order to safeguard the confidentiality and guarantee the security of informations that are transmitted through the Telecommunications Network. The technique is assessed on the physical layer of the reference model for open systems interconnection, OSI, a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/11/2012