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Harmonic Content (harmonic + content)
Selected AbstractsExpanding definitions of gain by taking harmonic content into account,INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2003Jeffrey Jargon Abstract We expand the definitions of power gain, transducer gain, and available gain by taking harmonic content into account. Furthermore, we show that under special conditions, these expanded definitions of gain can be expressed in terms of nonlinear large-signal scattering parameters. Finally, we provide an example showing how these expanded forms of gain and nonlinear large-signal scattering parameters can provide us with valuable information regarding the behavior of nonlinear models. Published 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13, 357,369, 2003. [source] The double vocal signature of crested penguins: is the identity coding system of rockhopper penguins Eudyptes chrysocome due to phylogeny or ecology?JOURNAL OF AVIAN BIOLOGY, Issue 5 2005Amanda Searby Parent-offspring recognition systems are used in bird colonies to avoid misdirected parental care. In penguins, where the risk of confusion is particularly high, recognition is achieved by acoustic signals that constitute highly efficient vocal signatures. Comparisons between species from the Pygoscelis and Aptenodytes genera have revealed interspecific differences on the encoding of information within the signatures which correlate with the presence/absence of nests in the colonies. However a recent study of individual recognition in macaroni penguins Eudyptes chrysolophus revealed diversity within nest-building species. This paper investigates whether the original and intermediate signature system found in macaroni penguins is shared by another species of Eudyptes, the rockhopper penguin E. chrysocome. Vocal signatures of rockhopper penguins were analysed and compared to macaroni penguins'. We used a methodology derived from the theory of information to determine which parameters of the call were likely to encode individual identity. Playbacks of modified calls in the field complemented the analyses, and parent-chick reunions were compared between the two species. Our results reveal a similar double signature system within the Eudyptes genus, which integrates information simultaneously from the temporal and spectral domains. This double encoding is made through the tempo given by the successive syllables of the call and the harmonic content of the call. While it confirms the hypothesis that signatures are simpler in nest-building species, this result reveals differences in the efficacies of signatures within this category. This suggests that other parameters such as the mean distance recognition should be considered to account for the differences in the encoding of the vocal signatures and in their resulting efficacies. [source] A single magnetic field exposure system for sequential investigation of real time and downstream cellular responsesBIOELECTROMAGNETICS, Issue 1 2004Raj R. Rao Abstract To be able to correlate real time membrane potential or ion flux changes with further downstream gene transcription responses due to extremely low frequency (ELF) electromagnetic field (EMF) exposure, we devised an experimental system consisting of a pair of symmetric circular coils. This system can be used on an inverted microscope stage (real time signaling) as well as inside controlled environment incubators (gene transcription end points). The system includes a unique, custom made switch box for blinding the experimental staff and a power amplifier. We report herein the design and characterization of the system with respect to parameters considered important in in vitro ELF,EMF exposure studies, including linear magnetic field distribution, compensation for microscope objective lens interference, heating effects of the coils, and harmonic content of the signals. Bioelectromagnetics 25:27,32, 2004. © 2003 Wiley-Liss, Inc. [source] Generalised algorithm of novel space vector modulation: for N -level three-phase voltage source inverterEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2008Hachemi Chekireb Abstract This paper concerns the development of a generalised algorithm of a novel space vector modulation (SVM) for N -level three-phase voltage source inverter. It is considering that the (N,1) DC input voltages of inverter are constant. The proposed method ensures initially the determination of the N3 inverter switching states, the extraction of the redundancies to obtain 3N(N -1),+,1 independent switching states and their organisation by sector in six distinct matrices Wk with k,=,(1,,,,,6). After that, these matrices Wk with k,=,(2,,,,,6) are ordered as the matrix W1 related to the first sector. So, the research of the three closest vectors to the reference vector is carried out only in first sector and for this purpose, the equivalent reference vector is introduced which is resulting from the rotation by ,(k,1),/3 of the reference vector. The on-line choice of the three vectors (three switching states of the inverter) is based on the distances between the equivalent reference vector and some vectors located in its vicinity in the (,,,) plane of the first sector. Moreover, a simple method for the calculation of the duty cycles for these three switching states is proposed which exploits directly the three shortest distances associated to these three selected vectors. The sequence of these three switching states over a sampling period is investigated in view to reduce the harmonic contents of the voltage output. The application is carried out on an N -level three-phase voltage source inverter, where N is an arbitrary odd integer. Finally, the phase voltage and its harmonic spectrum provided by a three-phase N- level inverter with N,=,(3,5,7,9,13,15) are presented to confirm the generalisation of this method. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||