Results 281 to 290 of about 7,200,285 (346)
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Low frequency photoelastic modulator

Applied Optics, 1984
In this paper, we propose a new excitation mode of a photoelastic modulator previously shown to perform low frequency polarization modulation. Photoacoustic and photothermal polarization spectroscopy is possible with this modulation scheme which has the specific advantages of large light throughput and freedom from mechanical vibrations.
J C, Canit, C, Pichon
openaire   +2 more sources

Research of frequency modulation to amplitude modulation with multi-frequency modulation

SPIE Proceedings, 2013
ABSTRACT For better performance of laser coupling in inertial confinement fusion (ICF), beam shaping of the focus spot is required. Among all the beam smoothing methods, the multi frequency modulation smoothing by spectral dispersion (MultiFM-SSD) proposed by LLE has the advantages of the faster smoothing and better operability.
Yuliang Zhou   +5 more
openaire   +1 more source

Double frequency modulation spectroscopy: high modulation frequency with low-bandwidth detectors

Applied Optics, 1985
In this paper, we describe experimental and theoretical investigations of two variations of frequency modulation (FM) spectroscopy that use two electrooptic modulators. In the first variation, both modulators are frequency modulators (FM–FM), and, in the second, one is a frequency modulator and one is an amplitude modulator (FM–AM).
D E, Cooper, T F, Gallagher
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Layered Orthogonal Frequency Division Multiplexing With Index Modulation

IEEE Systems Journal, 2019
In this paper, we propose a novel scheme termed layered orthogonal frequency division multiplexing with index modulation (L-OFDM-IM) to increase the spectral efficiency (SE) of OFDM-IM systems.
Jun Li   +5 more
semanticscholar   +1 more source

Frequency modulation versus amplitude modulation discrimination: Evidence for a second frequency modulation encoding mechanism

The Journal of the Acoustical Society of America, 1994
The encoding mechanisms for amplitude modulation (AM) and frequency modulation (FM) were investigated using AM–FM discrimination tasks. In the first experiment, AM and FM were set at equally detectable levels within a trial, and discrimination thresholds were obtained adaptively in a 3IFC task.
B W, Edwards, N F, Viemeister
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Modulated High‐Frequency Waves

Studies in Applied Mathematics, 1990
We construct asymptotic approximations to solutions of nonlinear hyperbolic conservation laws, when the initial data is small‐amplitude high‐frequency waves with modulated wave number. We show that the nonlinear multiwave interaction terms approach zero in the asymptotic limit, so that the wave components satisfy decoupled Burgers equations, provided a
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Frequency modulation

Electrical Engineering, 1940
openaire   +1 more source

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