Search results for "MODULATION"
showing 10 items of 948 documents
Halo-independent methods for inelastic dark matter scattering
2013
We present halo-independent methods to analyze the results of dark matter direct detection experiments assuming inelastic scattering. We focus on the annual modulation signal reported by DAMA/LIBRA and present three different halo-independent tests. First, we compare it to the upper limit on the unmodulated rate from XENON100 using (a) the trivial requirement that the amplitude of the annual modulation has to be smaller than the bound on the unmodulated rate, and (b) a bound on the annual modulation amplitude based on an expansion in the Earth's velocity. The third test uses the special predictions of the signal shape for inelastic scattering and allows for an internal consistency check of …
Large-scale Cosmic-Ray Anisotropies above 4 EeV Measured by the Pierre Auger Observatory
2018
We present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4 EeV measured using the Pierre Auger Observatory. For the energy bins [4,8] EeV and $E\geq 8$ EeV, the most significant signal is a dipolar modulation in right ascension at energies above 8 EeV, as previously reported. In this paper we further scrutinize the highest-energy bin by splitting it into three energy ranges. We find that the amplitude of the dipole increases with energy above 4 EeV. The growth can be fitted with a power law with index $\beta=0.79\pm 0.19$. The directions of the dipoles are consistent with an extragalactic origin of these anisotropies at all the energies considered. Addi…
Steered Response Power Localization of Acoustic Passband Signals
2017
The vast majority of localization approaches using phase transform (PHAT) consider that the sources of interest are wideband low-pass sources. While this may be the usual case for common audio signals such as speech, PHAT methods are affected negatively by modulation artifacts when the sources to be localized are passband signals. In these cases, steered response power PHAT localization becomes less robust. This letter analyzes the form of generalized cross-correlation functions with PHAT when passband acoustic signals are considered, proposing approaches for increasing the localization performance through the mitigation of these negative effects.
On the Design of Probe Signals in Wireless Acoustic Sensor Networks Self-Positioning Algorithms
2018
A wireless acoustic sensor network comprises a distributed group of devices equipped with audio transducers. Typically, these devices can interoperate with each other using wireless links and perform collaborative audio signal processing. Ranging and self-positioning of the network nodes are examples of tasks that can be carried out collaboratively using acoustic signals. However, the environmental conditions can distort the emitted signals and complicate the ranging process. In this context, the selection of proper acoustic signals can facilitate the attainment of this goal and improve the localization accuracy. This letter deals with the design and evaluation of acoustic probe signals all…
Doppler Estimation and Correction for JANUS Underwater Communications
2020
In recent years, underwater communications have seen a growing interest pushed by marine research, oceanography, marine commercial operations, offshore oil industry and defense applications. Generally, underwater communications employ audio signals which can propagate relatively far but are also significantly affected by Doppler distortions. In fact, physical properties of the water and spatial changes due to tides, currents and waves can cause channel variations or unwanted movements of the transmitter or receiver. This study shows how to compensate for the Doppler effect in transmission employing the JANUS standard, a popular modulation scheme for underwater communication. Differently for…
Experimental Evaluation of the Performance of a Three-Phase Five-Level Cascaded H-Bridge Inverter by Means FPGA-Based Control Board for Grid Connecte…
2018
Over the last decades, plants devoted to the generation of green energy significantly increased their number, together with the demand of same electrical energy, also stored in battery systems. This fact produced the growth of energy conversion systems with advanced performances with respect to the traditional ones. In this circumstance, multilevel converters play a significant role for their great advantages in performances, flexibility, fault-tolerability, employment of renewable energy sources and storage systems and finally yet importantly reduced filter requirements. In this context, this paper faces the performance of a cascaded H-bridge 5 level inverter in terms of harmonic distortio…
An inductive charger for automotive applications
2016
The inductive charging represents a valid solution for the power transfer in automotive applications. Due to the Inductive Power Transfer (IPT), the wireless battery charging of Electric Vehicles (EVs) provides several benefits. In this paper, an inductive charger which is particularly suitable for electrical bicycles is proposed. A practical realization of the system has been carried out, and the system has been tested in terms of working and efficiency. Through a Phase Shift Modulation (PSM), a power regulation has been implemented. The target power is 100 W.
Efficient contactless power transfer system for EVs
2016
Based on the inductive power transfer (IPT), the contactless approach allows safe and comfortable operations of battery charging for Electric Vehicles (EVs). In this paper, a contactless system particularly suitable for E-bike battery charging is proposed. A practical realization of the system has been carried out, aiming at the system evaluation in terms of working and efficiency. Through a phase shift modulation, a power regulation has been implemented. The target power level is 100 W.
An efficient wireless power transfer prototype for electrical vehicles
2017
Based on the inductive power transfer (IPT), the contactless approach allows safe and comfortable operations of battery charging for Electric Vehicles (EVs). In this paper, a contactless system particularly suitable for E-bike battery charging is proposed. A practical realization of the system has been carried out, aiming at the system evaluation in terms of working and efficiency. Through a phase shift modulation, a power regulation has been implemented. The target power level is 100 W.
Surface plasmon propagation in metal nanowires
2012
Plasmonic circuitry is considered as a promising solution-effectivetechnology for miniaturizing and integrating the next generation ofoptical nano-devices. The realization of a practical plasmonic circuitry strongly depends on the complete understanding of the propagation properties of two key elements: surface plasmons and electrons. The critical part constituting the plasmonic circuitry is a waveguide which can sustain the two information-carriers simultaneously. Therefore, we present in this thesis the investigations on the propagation of surface plasmons and the co-propagation of surface plasmons and electrons in single crystalline metal nanowires. This thesis is therefore divided into …