Browsing by Subject "Wide bands"

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    Ultra-wideband range estimation: Theoretical limits and practical algorithms
    (IEEE, 2008-09) Güvenç, İ.; Gezici, Sinan; Şahinoğlu, Z.
    The high time resolution of ultra-wideband (UWB) signals enables wireless devices to perform accurate range estimation. In order to realize UWB systems with accurate ranging capabilities, both theoretical limits on range estimation and practical algorithms that approach those limits should be investigated. This paper provides a survey of various UWB ranging algorithms and discusses their performance and complexity tradeoffs. In addition, theoretical limits on range estimation are discussed in terms of Cramer-Rao and Ziv-Zakai lower bounds. Index Terms- Ultra-wideband (UWB), time-of-arrival (TOA) estimation, ranging, Cramer-Rao lower bound (CRLB), Ziv-Zakai lower bound (ZZLB). ©2008 IEEE.
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    A wideband and a Wide-Beamwidth acoustic transducer design for underwater acoustic communications
    (IEEE, 2007-05) Elmaslı, I. Ceren; Köymen, Hayrettin
    This paper is concerned with the design of an efficient, wideband and a wide-beamwidth resonant acoustic transducer for high frequency use. The general transducer structure which has two back-to-back quarter wave thick 1-3 composite ceramic elements at resonance frequency is introduced. The transducer is employed for both transmit and receive modes. Design of transmitting and receiving transducers are discussed. Several transfer functions are derived and their effective bandwidths are calculated. It is shown that the phase angle difference between two acoustic ports in receive mode can be processed at the electrical ports to maintain better throughput. The paper includes future works to be done. It is concluded that the proposed structure can be used for applications of spread spectrum schemes in underwater communications. ©2006 IEEE.