886 research outputs found

    Television noise-reduction device

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    System greatly improves signal-to-noise ratio with little or no loss in picture resolution. By storage of luminance component, which is summed with chrominance component, system performs mathematical integration of basically-repetitive television signals. Integration of signals over interval of their repetition causes little change in original signals and eliminates random noise

    Television noise reduction device

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    A noise reduction system that divides the color video signal into its luminance and chrominance components is reported. The luminance component of a given frame is summed with the luminance component of at least one preceding frame which was stored on a disc recorder. The summation is carried out so as to achieve a signal amplitude equivalent to that of the original signal. The averaged luminance signal is then recombined with the chrominance signal to achieve a noise-reduced television signal

    Disorder regimes and equivalence of disorder types in artificial spin ice

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    The field-induced dynamics of artificial spin ice are determined in part by interactions between magnetic islands, and the switching characteristics of each island. Disorder in either of these affects the response to applied fields. Numerical simulations are used to show that disorder effects are determined primarily by the strength of disorder relative to inter-island interactions, rather than by the type of disorder. Weak and strong disorder regimes exist and can be defined in a quantitative way.Comment: The following article has been submitted to J. Appl. Phys. After it is published, it will be found at http://link.aip.org/link/?ja

    Diversity enabling equilibration: disorder and the ground state in artificial spin ice

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    We report a novel approach to the question of whether and how the ground state can be achieved in square artificial spin ices where frustration is incomplete. We identify two types of disorder: quenched disorder in the island response to fields and disorder in the sequence of driving fields. Numerical simulations show that quenched disorder can lead to final states with lower energy, and disorder in the driving fields always lowers the final energy attained by the system. We use a network picture to understand these two effects: disorder in island responses creates new dynamical pathways, and disorder in driving fields allows more pathways to be followed.Comment: 5 pages, 5 figure

    Spin canting induced large nonreciprocal Goos-Hänchen shifts

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    Recent studies on surface reflection illustrate how light beams can be laterally shifted from the position predicted by geometrical optics, the so called Goos-Hänchen effect. In antiferromagnets this shifts can be controlled with an external magnetic field. We show that a configuration in which spins cant in response to applied magnetic fields enhance possibilities of field controlled shifts. Moreover, we show that nonreciprocal displacements are possible, for both oblique and normal incidence, due to inherent nonreciprocity of the polariton phase with respect to the propagation direction. In the absence of an external field, reciprocal displacements occur
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