7,455 research outputs found

    Multiple Description Quantization of Sinusoidal Parameters

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    Multiple Description Trellis-Coded Quantization of Sinusoidal Parameters

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    Design of strapdown gyroscopes for a dynamic environment Semiannual report, Dec. 1967 - May 1968

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    Systems analysis, design, and operating characteristics of strapdown gyroscopes for dynamic environmen

    Quantum dynamics of local phase differences between reservoirs of driven interacting bosons separated by simple aperture arrays

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    We present a derivation of the effective action for the relative phase of driven, aperture-coupled reservoirs of weakly-interacting condensed bosons from a (3+1)-D microscopic model with local U(1) gauge symmetry. We show that inclusion of local chemical potential and driving velocity fields as a gauge field allows derivation of the hydrodynamic equations of motion for the driven macroscopic phase differences across simple aperture arrays. For a single aperture, the current-phase equation for driven flow contains sinusoidal, linear, and current-bias contributions. We compute the renormalization group (RG) beta function of the periodic potential in the effective action for small tunneling amplitudes and use this to analyze the temperature dependence of the low-energy current-phase relation, with application to the transition from linear to sinusoidal current-phase behavior observed in experiments by Hoskinson et al. \cite{packard} for liquid 4^{4}He driven through nanoaperture arrays. Extension of the microscopic theory to a two-aperture array shows that interference between the microscopic tunneling contributions for individual apertures leads to an effective coupling between apertures which amplifies the Josephson oscillations in the array. The resulting multi-aperture current-phase equations are found to be equivalent to a set of equations for coupled pendula, with microscopically derived couplings.Comment: 16 pages, 5 figures v2: typos corrected, RG phase diagram correcte

    Robust Parametric Audio Coding Using Multiple Description Coding

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    Wide-bandwidth high-resolution search for extraterrestrial intelligence

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    Research accomplished in the following areas is discussed: the antenna configuration; HEMT low-noise amplifiers; the downconverter; the Fast Fourier Transform Array; the backend array; and the backend and workstation
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