Search results for "Transmission"
showing 10 items of 2080 documents
Electronic States in Mesoscopic Systems
1992
Abstract Electronic states in disordered systems are studied within the Anderson model of localization. By means of the Green's function technique we derive the transmission coefficient for electronic states through mesoscopic samples. The transmission coefficient is shown to be not self-averaging due to strong spatial fluctuations of the amplitude of the eigenstates, which are obtained by direct diagonalization of the respective secular matrices. The wave functions display a multifractal behaviour, characterized by the set of generalized fractal dimensions and the singularity spectrum of the fractal measure.
A finite difference time domain model for the Titan ionosphere Schumann resonances
2007
[1] This paper presents a numerical approach to model the electrical properties of Titan's atmosphere. The finite difference time domain technique is applied to model the atmosphere of Saturn's satellite in order to determine Schumann resonant frequencies and electromagnetic field distributions at the extremely low frequency range. Spherical coordinates are employed, and periodic boundary conditions are implemented in order to exploit the symmetry in rotation of the celestial body. Results are compared with a previous model using the transmission line matrix method up to 180 km altitude. For the first time a numerical FDTD model up to 800 km altitude is carried out, and we report lower freq…
Analysis of Optical Systems, Contrast Depth, and Measurement of Electric and Magnetic Field Distribution on the Object's Surface in Mirror Electron M…
2011
Abstract The contrast depth is analyzed as well, that is the sensitivity of electron mirror microscope to disorders of homogeneity on the object (local magnetic and electric fields, surface relief). Because of the latter ones, electron trajectories feel disturbances (electrons acquire additional increment velocity in radial and azimuthal directions), which leads to the shift of the observed point on the screen and, as a consequence, to the image contrast. Since the electron energy, when reflected, tends to zero, electrons are influenced by heterogeneities for a long time. It causes high sensitivity to heterogeneities, up to the crossing of electron trajectories (caustics are generated). The…
Rateless codes mitigation technique in a turbulent indoor Free Space Optics link
2014
Free Space Optics (FSO) links are affected by several impairments and, among them, optical turbulence is the most important factor that can degrade the link quality. Due to the presence of this phenomenon, the signal irradiance detected by the receiver fluctuates, thus causing erasure errors and fading events. In this work, we present an indoor Free Space Optics link, in which several turbulence conditions are generated by using two heating elements. We show that the generated turbulence causes erasure errors and packet losses during the data transmission, and we also compare the statistical distribution of the samples with the theoretical models. Moreover, we demonstrate how the applicatio…
Nonlinear Evolution Equations, Quasi-Solitons and their Experimental Manifestation
1990
We review the typical experimental facts which characterize quasisolitons in one-dimensional real systems, in connection with their modeling by nonlinear partial differential equations.We consider these nonlinear waves or excitations in two different domains of the real world : the macroworld and the microworld. In the macroworld we examine typical one-dimensional devices : the electrical networks, the Josephson transmission lines and the optical fibers, where the localized waves or pulses can be simply and coherently created, easily observed and manipulated on a macroscopic scale. In the microworld, we consider the magnetic chains and polymers, where the indirect experimental signatures of…
Wave Modulations in the Nonlinear Biinductance Transmission Line
2001
Adding dissipative elements to a discrete biinductance transmission line which admits both low frequency (LF) and high frequency (HF) modes, dynamics of a weakly nonlinear modulated wave is investi...
LONG TIME DYNAMICS OF MODULATED WAVES IN A NONLINEAR DISCRETE LC TRANSMISSION LINE
2003
The long-time dynamics of modulated waves in a nonlinear LC transmission line is investigated. Considering the higher-order nonlinear Schrodinger equation, we define analytically the conditions leading to the instability of modulated waves. We show that two kinds of instabilities may develop in the network depending on the frequency range of the chosen carrier wave and on the magnitude of its initial amplitude, which is confirmed by our numerical simulations. The nonreproducibility of numerical experiments on modulated waves is also considered.
Solitons in Nonlinear Transmission Lines
1996
Although solitary waves and solitons were originally discovered in the context of water waves and lattice dynamics, consideration of these physical systems (which will be considered in Chaps.5 and 8) leads to calculations far too involved for pedagogical purposes. Thus, for an introduction to the soliton concept, we therefore consider simple wave propagation in electrical nonlinear transmission lines and electrical networks.
Transmission of ultra-cold neutrons through guides coated with materials of high optical potential
2014
Abstract We have measured the transmission of ultra-cold neutrons (UCN) through tubes coated on the inside with materials of high optical potentials. The best transmission value, T, normalised to 1 m long UCN guides was obtained with a beryllium coated quartz guide, T=(99.0±1.0)%. Furthermore, excellent transmission coefficients were found for (i) a glass tube coated with NiMo(88/12), T=(97.3 ±0.6)%, (ii) a NiMo(85/15) guide made by the replication technique, T=(97.1 ±0.8)% and (iii) a glass guide coated with NiMo(82/18), T=(96.3 ±2.1)%. The results demonstrate that UCN guides made from coated glass tubes have the same excellent transmission properties as those produced with the replication…
DSP Online Algorithms for The ATLAS TileCal Read-Out Drivers
2007
TileCal is the hadronic tile calorimeter of the ATLAS experiment at LHC/CERN. The central element of the back-end system of the TileCal detector is the read-out driver (ROD).The main components of the TileCal ROD are the digital signal processors (DSPs) placed on the processing unit (PU) daughterboards. This paper presents a detailed description of the code developed for the DSPs. The code is divided into two different parts: the first part contains the core functionalities and the second part the reconstruction algorithms. The core acts as an operating system and controls configuration, data reception and transmission and synchronization between front-end data and the timing, trigger and c…