1000 resultados para band alignment
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L’étiquette « homme-orchestre » est apposée à une grande variété de musiciens qui se distinguent en jouant seuls une performance qui est normalement interprétée par plusieurs personnes. La diversité qu’a pu prendre au cours du temps cette forme n’est pas prise en compte par la culture populaire qui propose une image relativement constante de cette figure tel que vue dans les films Mary Poppins (1964) de Walt Disney et One-man Band (2005) de Pixar. Il s’agit d’un seul performeur vêtu d’un costume coloré avec une grosse caisse sur le dos, des cymbales entre les jambes, une guitare ou un autre instrument à cordes dans les mains et un petit instrument à vent fixé assez près de sa bouche pour lui permettre d’alterner le chant et le jeu instrumental. Cette thèse propose une analyse de l’homme-orchestre qui va au-delà de sa simple production musicale en situant le phénomène comme un genre spectaculaire qui transmet un contenu symbolique à travers une relation tripartite entre performance divertissante, spectateur et image. Le contenu symbolique est lié aux idées caractéristiques du Siècle des lumières tels que la liberté, l’individu et une relation avec la technologie. Il est aussi incarné simultanément par les performeurs et par la représentation de l’homme-orchestre dans l’imaginaire collectif. En même temps, chaque performance sert à réaffirmer l’image de l’homme-orchestre, une image qui par répétitions est devenue un lieu commun de la culture, existant au-delà d’un seul performeur ou d’une seule performance. L’aspect visuel de l’homme-orchestre joue un rôle important dans ce processus par une utilisation inattendue du corps, une relation causale entre corps, technologie et production musicale ainsi que par l’utilisation de vêtements colorés et d’accessoires non musicaux tels des marionnettes, des feux d’artifice ou des animaux vivants. Ces éléments spectaculaires divertissent les spectateurs, ce qui se traduit, entre autres, par un gain financier pour le performeur. Le divertissement a une fonction phatique qui facilite la communication du contenu symbolique.
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A novel technique for obtaining dual-hand circular polarization (CP) radiation of a single-feed circular microstrip antenna in proposed and demonstrated. By embedding two pain of arc shaped slots of proper lengths close to the boundary of a circular patch, and protruding one of the arc-shaped slots with a narrow slit, the circular microstrip antenna can perform dual-hand CP radiation using a single probe feed. Details of the antenna design
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A microstrip antenna with large bandwidth is developed using a parasitic technique . Compared to the available wide-baud antennas,the proposed antenna structure is very compact and gives a lessdistorted radiation pattern with frequency . An impedance bandwidth,eight times that of a conventional patch antenna of the same size, Isachieved. The concept of coupled microstrip line model Is extended fortheoretical interpretation of the impedance loci
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The design and development of an L-band printed dipole antenna. optimized for wide-band applications near first resonance, is reported. This design has achieved more than 48% impedance bandwidth (VSWR 2:1), without degrading its overall radiation efficiency
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Experimental studies on a compact dual frequency microstrip antenna are presented. This antenna configuration provides an area reduction of 40% compared to a standard rectangular antenna operating at the same frequency without much degradation of the gain. The antenna structure can be modified to achieve the desired ratio between the two resonant frequencies
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A new compact dual-band, dual-polarized microstrip antenna is presented. 7'iris antenna resonates at two frequencies with different polarizations: a linearly polarized one for terrestrial communication, and a circularly polarized one for satellite mobile communication. This antenna also provides an area reduction of 70% compared to a standard rectangular patch antenna
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Bandwidth enhancement of a rectangular microstrip antenna using a T-shaped microstrip feed is explored in this paper. A 2:1 VSWR impedance bandwidth of 23% is achieved by employing this technique. The far-field patterns are stable across the pass band. The proposed antenna can be used conveniently in broadband communications
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In this paper, the generation of a multiwavelength laser source from a Brillouin -Erbium fiber laser in the long wavelength band (L-band) region is experimentally demonstrated. The proposed laser system utilizes a Fabrv-Perot cavity formed by fiber-loop mirrors. Twenty-four lines of Brillouin-Stokes with line spacings of 10 GHz are obtained in the L-band region
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In this paper, microstrip lines magnetically coupled to splitring resonators (SRRs) are conquved to electromagnetic bundgup (EBG) nr,rrostrip lines in terns q/ their stop-heard penjbrnmrnce and dimensions. In bath types o/ trunsmis•siou lines, signal propagation is inhibited in it certain jequency bwuL For EBG microstrip lines, the central frequency of such a forbidden band is determined by the period of the structure, whereas in SRR-hased microstrip lines the position of the frequency gap depends on the quasi-static resonant frequency of the rings. The main relevant conrributiun of this paper is to provide a tuning procedure to control the gap width in SRR microstrip lines, and to show that by using SRRs, device dimensions ale much smaller than those required by EBGs in order to obtain similar stop-banal performance. This has been demonstrated by fill-wave electromagnetic simulations and experimentally verified from the characterization ql two fabricated microstrip lines: one with rectangular SRRs etched on the upper substrate side, and the other with a periodic perturbation cf'strip width. For similar rejection and 1-(;H,. gap width centered at 4.5 Gllz, it has been found that the SRR microstrip line is•,fve times shorter. In addition, no ripple is appreciable in the allowed band for the .SRR-hared structure, whereas due to dispersion, certain mismatch is expected in the EBG prototype. Due to the high-frequency selectivity, controllable gap width, and small dimensions, it is believed that SRR coupled to planar transmission lines can have an actual impact on the design of stop-band filters compatible with planar technology, and can be an alternative to present solutions based on distributed approaches or EBG
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Design, development and experimental observations of a L: band printed dipole antenna is presented.Bandwidth enhancement is achieved by end-loading or the dipole arms. Using the present technique Impedance bandwidth van be enhanced up to 50% without degrading the efficiency of the antenna.
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A novel design of a computer electronically reconfigurable dual frequency dual polarized single feed hexagonal slot loaded microstrip antenna in L-band is introduced in this chapter. pin diodes are used to switch the operating frequencies considerably without much affecting the radiation characteristics and gain. the antenna can work with a frequency ratio varying in the wide range from 1.2 to 1.4. the proposed design has an added advantage of size reduction up to 72.21% and 46.84% for the two resonating frequencies compared to standard rectangular patches. the design also gives considerable bandwidth of up to 2.82% and 2.42 % for the operating frequencies.
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Department of Electronics, Cochin University of Science and Technology
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Department of Physics, Cochin University of Science and Technology