Topic
Frequency response
About: Frequency response is a research topic. Over the lifetime, 25705 publications have been published within this topic receiving 332249 citations.
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TL;DR: In this article, the effects of system and medium perturbations, and deviations of signal field statistics from usual assumptions, on the performance of adaptive arrays are investigated, and the emphasis is placed on the determination of the sensitivity of the adaptive processors to perturbation, rather than its overall performance in a representative background.
Abstract: An investigation of the effects of system and medium perturbations, and the deviations of signal field statistics from usual assumptions, on the performance of adaptive arrays is presented. The emphasis is placed on the determination of the sensitivity of the adaptive processors to perturbations, rather than its overall performance in a representative background. The numerical results are limited to CW signals, and a frequency domain element space adaptive beam-former is modeled for the majority of the results. Representative comparative results including frequency domain beam space, time domain element space, and matched array processors are also given.
94 citations
94 citations
TL;DR: In this article, a modified beam theory is presented by incorporating surface elasticity and the Galerkin method is used to give a reduced-order model of the problem and numerical results show that the mechanical buckling and free vibration phenomena of nanobeams are size-dependence.
Abstract: A modified continuum model of the nanoscale beams is presented by incorporating surface elasticity in this paper. The classical beam theory is adopted to model the bulk, while the bulk stresses along the surfaces of the bulk substrate are required to satisfy the surface balance equations of the continuum surface elasticity. On the basis of this modified beam theory the governing equation of the nanobeam is derived where the effect of the geometry nonlinearity is also considered. The Galerkin method is used to give a reduced-order model of the problem. Beams made from two materials: aluminum and silicon are chosen as examples. The numerical results show that the mechanical buckling and free vibration phenomena of nanobeams are size-dependence. The effects of the surface energies on the critical axial force of buckling, post-buckling and linear free vibration frequency are discussed. Finally, the amplitude frequency response is given numerically through the incremental harmonic balanced method.
94 citations
TL;DR: In this article, the effects of controlled damping on the amplitude and frequency response profiles of an elastically mounted cylinder in cross-flow were studied. But, because of the influence of the Reynolds number, the traditional labels of high mass-damping and low massdamping are incomplete with regard to predicting a large or small-amplitude response profile.
94 citations
TL;DR: In this paper, the authors explore the high-frequency capability of quantum-well infrared photodetectors using a microwave-rectification technique and show that the intrinsic photoconductive lifetime for these devices in the high biasing field regime is in the range of 5-6 ps.
Abstract: We explore the high-frequency capability of quantum-well infrared photodetectors using a microwave-rectification technique. We characterize a variety of devices with barrier thicknesses from 234 to 466 /spl Aring/ and number of wells from 4 to 32. Our packaged detectors have a relatively flat frequency response up to about 30 GHz. These experiments indicate that the intrinsic photoconductive lifetime for these devices in the high-biasing field regime is in the range of 5-6 ps.
94 citations