30,925 research outputs found
Digital Demodulator for BFSK waveform based upon Correlator and Differentiator Systems
The present article relates in general to digital demodulation of Binary Frequency Shift Keying (BFSK waveform) . New processing methods for demodulating the BFSK-signals are proposed here. Based on Sampler Correlator, the hardware consumption for the proposed techniques is reduced in comparison with other reported. Theoretical details concerning limits of applicability are also given by closed-form expressions. Simulation experiments are illustrated to validate the overall performance
Can intrinsic noise induce various resonant peaks?
We theoretically describe how weak signals may be efficiently transmitted
throughout more than one frequency range in noisy excitable media by kind of
stochastic multiresonance. This serves us here to reinterpret recent
experiments in neuroscience, and to suggest that many other systems in nature
might be able to exhibit several resonances. In fact, the observed behavior
happens in our (network) model as a result of competition between (1) changes
in the transmitted signals as if the units were varying their activation
threshold, and (2) adaptive noise realized in the model as rapid
activity-dependent fluctuations of the connection intensities. These two
conditions are indeed known to characterize heterogeneously networked systems
of excitable units, e.g., sets of neurons and synapses in the brain. Our
results may find application also in the design of detector devices.Comment: 10 pages, 2 figure
Chromaticity effects in microlensing by wormholes
Chromaticity effects introduced by the finite source size in microlensing
events by presumed natural wormholes are studied. It is shown that these
effects provide a specific signature that allow to discriminate between
ordinary and negative mass lenses through the spectral analysis of the
microlensing events. Both galactic and extragalactic situations are discussed.Comment: To appear in Modern Physics Letters A, 200
Nonequilibrium many-body quantum dynamics: from full random matrices to real systems
We present an overview of our studies on the nonequilibrium dynamics of
quantum systems that have many interacting particles. Our emphasis is on
systems that show strong level repulsion, referred to as chaotic systems. We
discuss how full random matrices can guide and support our studies of realistic
systems. We show that features of the dynamics can be anticipated from a
detailed analysis of the spectrum and the structure of the initial state
projected onto the energy eigenbasis. On the other way round, if we only have
access to the dynamics, we can use it to infer the properties of the spectrum
of the system. Our focus is on the survival probability, but results for other
observables, such as the spin density imbalance and Shannon entropy are also
mentioned.Comment: 14 pages, 7 figures, chapter for the book "Thermodynamics in the
Quantum Regime - Recent Progress and Outlook
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