Increased performance, fairness, and security remain important goals for service providers. In this work, we design an integrated distributed monitoring, traffic conditioning, and flow control system for higher perfor...
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We review the design and experimental results of three new AlGaN/GaN high elec.ron-mobility transistor monolithic microwave integrated circuits: a voltage-controlled oscillator (VCO), a single-pole-double-throw switch...
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We review the design and experimental results of three new AlGaN/GaN high elec.ron-mobility transistor monolithic microwave integrated circuits: a voltage-controlled oscillator (VCO), a single-pole-double-throw switch (SPOT), and a resistive field-effect transistor mixer. The VCO exhibits frequency range between 8.5-9.5 GHz with maximum output power of 35 dBm (at Vds = 30 V) across a 50-Ω load. The L/S band SPOT switch at 0.9, 1.8, and 2.1 GHz was measured to have 0.87-, 0.96-, 1-dB insertion loss and 46-, 42-, and 41-dB isolation, respectively. The switch also shows linear performance for the power levels up to l W in the insertion mode. A singly ended X -band resistive mixer has exhibited very low intermodulation, less than -60 dBc for the second and third harmonics of the IF at the RF power level of 10 dBm, and high power handling, P1 dB is estimated to be at least 1 W, with the conversion loss of 17 dB.
We have studied the reliability problems in the degradation of the data retention characteristics of the stacked-gate flash EEPROM devices with the new interpoly dielec.ric of an Oxide-Nitride-Oxide-Nitride (ONON) lay...
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We consider a low-complexity adaptive MIMO transmission approach for spatially correlated channels. The proposed sch.me adaptively switches between different transmission modes depending on the changing channel condit...
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All elec.rical activities in the nervous system, including communications between cells and the influence of hormones and drugs on cell function, are regulated by membrane ion channels. Therefore understanding their m...
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Traditional methods for partial envelope analysis run into difficulties in the presence of tremolo and noise. This paper investigates an alternative method of analysis that uses a variety of non-linear warping techniq...
Traditional methods for partial envelope analysis run into difficulties in the presence of tremolo and noise. This paper investigates an alternative method of analysis that uses a variety of non-linear warping techniques to match a synthetic envelope template to the partial envelope. Generation of suitable templates is discussed and the variety of implementations for the warping algorithm is examined. A complete procedure for matching the template is then explained and justified. Application of this procedure to partial envelope analysis of flute sounds is described and the results presented demonstrate the best choice of warping implementation. This technique allows for better envelope segmentation thus enabling improved modelling in representations such as the Timbre Model [1].
We consider a layered space-frequency (LSF) extension to bit-interleaved coded modulation (BICM) for MIMO-OFDM systems. We derive tight analytical bounds for the coded BER when using zero-forcing (ZF) detectors. The a...
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We consider a layered space-frequency (LSF) extension to bit-interleaved coded modulation (BICM) for MIMO-OFDM systems. We derive tight analytical bounds for the coded BER when using zero-forcing (ZF) detectors. The analysis does not rely on standard BICM expurgation techniques, and provides exact expressions for the codeword pairwise error probability at high SNR. We show that the LSF extension achieves the same diversity order as non-layered systems, while also achieving significant cant SNR gains when the number of transmit antennas is large. We quantify the SNR gain and show that it is a function of the antenna configuration only, and is independent of the modulation and coding parameters. We also present simulation results for MIMO extensions to IEEE 802.11a OFDM WLANs
The coupling between the desired coplanar-waveguide (CPW) mode and the unwanted coupled slotline mode is presented for finite-ground CPWs with unequal ground-plane widths. Measurements, quasi-static conformal mapping,...
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The coupling between the desired coplanar-waveguide (CPW) mode and the unwanted coupled slotline mode is presented for finite-ground CPWs with unequal ground-plane widths. Measurements, quasi-static conformal mapping, and finite-difference time-domain analysis are performed to determine the dependence of the slotline-mode excitation on the physical dimensions of the finite-ground coplanar line and on the frequency range of operation. It is shown that the ratio of the slotline mode to the CPW mode can be as high as 10 dB. Air-bridges are shown to reduce the slotline mode by 15 dB immediately after the air-bridge, but the slotline mode fully reestablishes itself within 2000 μm of the air-bridge. Furthermore, these results are independent of frequency.
For human beings, vision is one of the most important senses in interacting with the surrounding environment, as well as with any tools that require visual communication. As such, the ability to interact effectively w...
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For human beings, vision is one of the most important senses in interacting with the surrounding environment, as well as with any tools that require visual communication. As such, the ability to interact effectively with computers through typical graphic user interfaces (GUIs) is greatly affected by any refractive errors present in an individual's visual system. If the refractive errors can be mathematically modeled, a system for overcoming these aberrations can be devised which can increase the effective human-computer interaction for these individuals. Several methods, such as Adaptive Optics, have been proposed that attempt to solve this problem using elec.ro-mechanical devices. These methods are costly and impractical, preventing most visually impaired individuals from benefiting from their use. In contrast, an image-processing method, based on deconvolution techniques, has recently been proposed for the pre-compensation of images to be displayed in a computer. This method is much more practical, being completely implemented in software, and has achieved encouraging results. Previous results have yielded an average 50% increase in visual efficiency in the compensation of a known artificial aberration introduced into the field of vision of experimental subjects. This paper describes the difficulties encountered with the present software-only compensation and proposes several methods for overcoming these obstacles. The difficulties, as well as the proposed solutions, are described theoretically and followed by examples using a lens system showing the improvement over previous methods. Copyright 2005 ISA. All Rights Reserved.
This paper presents reconfigurable RF integrated circuits (ICs) for a compact implementation of an intelligent RF front-end for multiband and multistandard applications. Reconfigurability has been addressed at each le...
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This paper presents reconfigurable RF integrated circuits (ICs) for a compact implementation of an intelligent RF front-end for multiband and multistandard applications. Reconfigurability has been addressed at each level starting from the basic elements to the RF blocks and the overall front-end architecture. An active resistor tunable from 400 to 1600 Ω up to 10 GHz has been designed and an equivalent model has been extracted. A fully tunable active inductor using a tunable feedback resistor has been proposed that provides inductances between 0.1-15 nH with Q > 50 in the C-band. To demonstrate reconfigurability at the block level, voltage-controlled oscillators with very wide tuning ranges have been implemented in the C-band using the proposed active inductor, as well as using a switched-spiral resonator with capacitive tuning. The ICs have been implemented using 0.18-μm Si-CMOS and 0.18-μm SiGe-BiCMOS technologies.
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