9,837 research outputs found
Codes Cross-Correlation Impact on S-curve Bias and Data-Pilot Code Pairs Optimization for CBOC Signals
The aim of this paper is to analyze the impact of spreading codes cross-correlation on code tracking performance, and to optimize the data-pilot code pairs of Galileo E1 Open Service (OS) Composite Binary Offset Carrier (CBOC) signals. The distortion of the discriminator function (i.e., S-curve), due to data and pilot spreading codes cross-correlation properties, is evaluated when only the data or pilot components of CBOC signals are tracked, considering the features of the modulation schemes. Analyses show that the S-curve bias also depends on the receiver configuration (e.g., the tracking algorithm and correlator spacing). In this paper, two methods are proposed to optimize the data-pilot code pairs of Galileo E1 OS. The optimization goal is to obtain minimum average S-curve biases when tracking only the pilot components of CBOC signals for the specific correlator spacing. The S-curve biases after optimization processes are analyzed and compared with the un-optimized results. It is shown that the optimized data-pilot code pairs could significantly mitigate the intra-channel (i.e., data and pilot) codes cross-correlation,and then improve the code tracking performance of CBOC signals
KNbO3 single crystal growth by the radio frequency heating Czochralski method
A radio frequency heating Czochralski technique to obtain single crystal KNbO3 is first presented. The technological parameters of KNbO3 crystal growth by the Czochralski technique and its pulling conditions were studied in detail. The experiments on second harmonic generation using 1.06 micrometer Nd:YAG laser in KNbO3 have been conducted. The second harmonic efficiency for upconversion of KNbO3 is found to be as high as that of NaBa2Nb5O15. An automatic scanning measurement for the optical homogeneity of KNbO crystal is also described. KNbO3 is revealed to be a potentially useful nonlinear material for optical device applications
Leptogenesis with Friedberg-Lee Symmetry
We consider the  symmetric Friedberg-Lee (FL) symmetry for the
neutrino sector and show that a specific FL translation leads to the
tribimaximal mixing pattern of the Maki-Nakagawa-Sakata (MNS) matrix. We also
apply the symmetry to the type-I seesaw framework and address the baryon
asymmetry of the universe through the leptogenesis mechanism. We try to
establish a relation between the net baryon asymmetry and CP phases included in
the MNS matrix.Comment: Talk given at International Workshop on Dark Matter, Dark Energy and
  Matter-Antimatter Asymmetry, Hsinchu, Taiwan, 20-21 Nov. 2009, to be
  published in Modern Physics Letters A, reference adde
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