Results 261 to 270 of about 541,984 (296)
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Jim Blinn's corner-return of the Jaggy (high frequency filtering)
IEEE Computer Graphics and Applications, 1989The antialiasing problem of filtering out high frequencies before sampling is considered. The techniques examined are simple filters, box filters, the triangle or tent filter, Gaussian and similarly shaped filters, and the ideal filter. The use of subsampling and the effect of D/A (digital-to-analog) converters are discussed. >
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Characterizing Antennas in the Time and Frequency Domains [Education Corner]
IEEE Antennas and Propagation Magazine, 2018The antenna definitions standard [1] currently has no terms that describe antenna performance in the time domain, possibly due to the complexity of the equations. However, if the antenna equations are expressed using quantities related to the square root of power, then simple expressions are obtained that are valid in both the frequency and time ...
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A revisited three-cornered hat method for estimating frequency standard instability
IEEE Transactions on Instrumentation and Measurement, 1993The three-cornered hat method used for evaluating the individual noise contributions of three frequency standards in a stability measurement is reexamined. The hypothesis of uncorrelation of the standards is not assumed a priori, as it is considered a cause of negative estimated variances. The introduction of covariances of measured data, together with
A. Premoli, P. Tavella
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Two Empirical Double-Corner-Frequency Source Spectra and Their Physical Implications
Bulletin of the Seismological Society of America, 2020ABSTRACTWe introduce double-corner-frequency (DCF) source spectral models JA19 and JA19_2S, which, in conjunction with a stochastic ground-motion model, can reproduce the mean peak ground acceleration (PGA) and mean peak ground velocity (PGV) of the Next Generation Attenuation-West 2 database for magnitudes 3.3–7.3.
Chen Ji, Ralph J. Archuleta
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Source Parameters Observable from the Corner Frequency of Earthquake Spectra
Bulletin of the Seismological Society of America, 2002The Brune (1970) classic theory's suggestion that the source radius be determined from the corner frequency of earthquake spectra is based on a number of insufficiently constrained assumptions that make the result virtually a guess. Viewing earthquakes as displacement-discontinuity sources radiating ω -2 spectra indicates that the two other parameters ...
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Feature Tunable Trihedral Corner Reflector Based on Active Frequency Selective Surface
2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT), 2019The trihedral corner is a common structure with strong radar cross section (RCS) existing in radar targets. It is detected and recognized easily by radar since its scattering characteristics are fixed once fabricated. In this paper, the feature tunable trihedral corner reflector is designed based on active frequency selective surface (AFSS).
Lei Liu +4 more
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Corner reflector antenna with the same beamwidth in two frequency bands
Electronics and Communications in Japan (Part I: Communications), 1993AbstractThe demand for expanded mobile communication capacity is increasing rapidly. It is expected that in addition to the currently used 900‐MHz band, the 1.5‐GHz band will have to be utilized. An antenna is designed so that it has the same sector beamwidth in both bands.
Tamami Suzuki, Kenichi Kagoshima
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Two empirical double-corner frequency source spectra and their source physics implications
2021<p>The best-known part of Brune&#8217;s (1970) spectral model is the single corner&#160;<em>f<sup>&#8211;2&#160;</sup></em>source spectrum. However, Brune noted that a more realistic heterogeneous rupture would have a source displacement spectrum with ...
Ralph Archuleta, Chen Ji
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Statistical Models and Frequency-Dependent Corner Models for Passive Devices
9th International Symposium on Quality Electronic Design (isqed 2008), 2008We present the statistical SPICE models and associated corner models of passive devices (such as capacitors and resistors) in VLSI semiconductor technologies. The capacitor devices include decoupling capacitors, metal- insulator-metal capacitors (MIMCAPs), junction capacitors, MOS varactors, BEOL metal capacitors, etc.
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Modulated corner reflector using frequency selective surfaces for FMCW radar applications
2015 European Microwave Conference (EuMC), 2015This work describes a modulated transponder based on a corner reflector where at least one of the metallic surfaces is replaced by an actively-controlled frequency selective surface (FSS) loaded with switching PIN diodes. The reflectivity of the faces loaded with the FSS changes with the bias of the diodes modulating the radar cross-section of the ...
Lazaro, A. +3 more
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