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51.
Analogue switch for very low-voltage applications 总被引:2,自引:0,他引:2
Munoz F. Ramirez-Angulo J. Lopez-Martin A. Carvajal R.G. Torralba A. Palomo B. Kachare M. 《Electronics letters》2003,39(9):701-702
A new analogue switch suitable for operation at very low-voltage supply in a standard CMOS technology is presented. The proposed switch is based on 'quasi-floating-gate' transistors and has a simple and compact structure. For illustrative purposes, two sample-and-hold circuits operating from a single supply voltage close to the threshold voltage of a transistor, and using the proposed technique, are presented. Experimental results obtained from prototypes in a 1.5 /spl mu/m CMOS technology are provided. 相似文献
52.
M A Fennir J A Landry H S Ramaswamy V G S Raghavan 《The Journal of microwave power and electromagnetic energy》2003,38(3):189-196
This study investigates the effect of extraction methods on the color of date syrup and the potential use of microwave power for syrup processing. Sugar solutions were extracted from dates by boiling, soaking and blending. Color and sugar content of the extracted solutions were measured, and the percentage of sugar extracted form the total fruit sugar determined. Boiling was found to be the most efficient method of extraction whereby 74% of total samples sugar was extracted. In contrast, only 54.2% of fruit sugar was extracted by blending and 42% by soaking. In addition, solutions extracted by soaking and blending had a foaming problem in the subsequent concentration process. The extraction method had no effect on the product final color. The extracted solution was concentrated using two heating methods: conventional and microwave heating at a 600 W capacity and a frequency of 2450 MHz applied at three power levels: 10, 7, and 6. In the heating process, 180 minutes were needed to achieve a 77% degrees Brix using convective heating, while it took 81, 138, and 166 minutes of microwave heating at power level 10, 7, and 6, respectively to achieve the same concentration. Water activity of the syrup was measured within a sugar content range of 50 to 80% degrees Brix and the sugar concentration at which the product is shelf stable was determined at 76%. 相似文献
53.
Valentian A. Thomas O. Vladimirescu A. Amara A. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2004,12(6):662-669
A simple, yet realistic physics-based model is introduced to describe the subthreshold drain current of a MOSFET taking into account the body- and drain-voltage dependencies, including the short channel effects. This model, verified by SPICE simulations, describes adequately the pseudotriode and pseudosaturation regions of MOS transistors operated below V/sub T/. It can be applied for predicting bulk- or partially depleted (PD) SOI CMOS circuit operation. Analytical expressions derived for the logic switching threshold and delay are applied to predict the performance of CMOS-SOI inverters. 相似文献
54.
Algebraic theory of optimal filterbanks 总被引:1,自引:0,他引:1
We introduce an optimality theory for finite impulse response (FIR) filterbanks using a general algebraic point of view. We consider an admissible set /spl Lscr/ of FIR filterbanks and use scalability as the main notion based on which performance of the elements in /spl Lscr/are compared. We show that quantification of scalability leads naturally to a partial ordering on the set /spl Lscr/. An optimal solution is, therefore, represented by the greatest element in /spl Lscr/. It turns out that a greatest element does not necessarily exist in /spl Lscr/. Hence, one has to settle with one of the maximal elements that exist in /spl Lscr/. We provide a systematic way of finding a maximal element by embedding the partial ordering at hand in a total ordering. This is done by using a special class of order-preserving functions known as Schur-convex. There is, however, a price to pay for achieving a total ordering: there are infinitely many possible choices for Schur-convex functions, and the optimal solution specified in /spl Lscr/ depends on this (subjective) choice. An interesting aspect of the presented algebraic theory is that the connection between several concepts, namely, principal component filterbanks (PCFBs), filterbanks with maximum coding gain, and filterbanks with good scalability, is clearly revealed. We show that these are simply associated with different extremal elements of the partial ordering induced on /spl Lscr/ by scalability. 相似文献
55.
56.
Ron Wilson 《电子设计技术》2006,13(11):126-126
无线USB的前途似乎无与伦比——它能消除那些把大家桌面弄得像鼠窝一样小小的不怎么灵便的电缆。但事实上,只有需要大量的外设时无线USB设备才有优势,而且它必须非常微型而廉价,否则带来的麻烦远多于缠绕的电缆。因此,插在PC USB端口作为无线基站的硬件锁就必须有尽可能高的集成度。但一片芯片中要包含USB有线接口、控制器、无线基带和RF电路,技术上还无法实现。下面我们将看到一家供应商Wisalr的一种可量产参考设计,它是如何接近于解决这个问题的。 相似文献
57.
Akhlesh Lakhtakia Joseph A. Sherwin 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(1):19-23
The potential of orthorhombic materials for perfect lenses is theoretically examined. 相似文献
58.
An accurate printer model that is efficient enough to be used by halftoning algorithms is proposed. The proposed signal processing model (SPM) utilizes a physical model to train adaptive linear combiners (ALCs), after which the average exposure of each subpixel for any input pattern can be calculated using the optimized weight vector. The SPM can be used to model multi-level halftoning and resolution enhancement, as well as traditional halftoning. The SPM is comprised of a single ALC layer followed by a peak-to-average ratio (PAR) correction layer, which serves to produce a PAR of less than 1.5 in the modeled exposure. The PCN (PAR correction network) employs one ALC/pixel and exploits the physics governing the characteristics of exposure in small regions. A relatively small number of training patterns suffices to train the SPM. 相似文献
59.
Chou Y.C. Leung D. Lai R. Grundbacher R. Barsky M. Kan Q. Tsai R. Wojtowicz M. Eng D. Tran L. Block T. Liu P.H. Nishimoto M. Oki A. 《Electron Device Letters, IEEE》2003,24(6):378-380
The authors have investigated the reliability performance of G-band (183 GHz) monolithic microwave integrated circuit (MMIC) amplifiers fabricated using 0.07-/spl mu/m T-gate InGaAs-InAlAs-InP HEMTs with pseudomorphic In/sub 0.75/Ga/sub 0.25/As channel on 3-in wafers. Life test was performed at two temperatures (T/sub 1/ = 200 /spl deg/C and T/sub 2/ = 215 /spl deg/C), and the amplifiers were stressed at V/sub ds/ of 1 V and I/sub ds/ of 250 mA/mm in a N/sub 2/ ambient. The activation energy is as high as 1.7 eV, achieving a projected median-time-to-failure (MTTF) /spl ap/ 2 /spl times/ 10/sup 6/ h at a junction temperature of 125 /spl deg/C. MTTF was determined by 2-temperature constant current stress using /spl Delta/G/sub mp/ = -20% as the failure criteria. The difference of reliability performance between 0.07-/spl mu/m InGaAs-InAlAs-InP HEMT MMICs with pseudomorphic In/sub 0.75/Ga/sub 0.25/As channel and 0.1-/spl mu/m InGaAs-InAlAs-InP HEMT MMICs with In/sub 0.6/Ga/sub 0.4/As channel is also discussed. The achieved high-reliability result demonstrates a robust 0.07-/spl mu/m pseudomorphic InGaAs-InAlAs-InP HEMT MMICs production technology for G-band applications. 相似文献
60.
E. A. Gurieva P. P. Konstantinov L. V. Prokof D. A. Pshenaĭ-Severin M. I. Fedorov Yu. I. Ravich 《Semiconductors》2006,40(7):763-767
The coefficients of thermopower and electrical and thermal conductivity in the PbTe0.8Se0.1 S 0.1 solid solution with electron concentration (4.6–54) × 1018 cm?3 are studied in the range of 85–300 K (and in some cases up to 700 K). The temperature dependences of electrical and thermal conductivity indicate that the low-temperature electron and phonon scattering initiated by the off-center impurity of sulfur exists. The temperature dependences of the electronic and lattice components of thermal conductivity are calculated in the approximation of a parabolic spectrum and electron scattering by acoustic phonons and neutral substitutional impurities. The lattice thermal conductivity is found to have a feature in the form of a shallow minimum in the range of 85–250 K. A similar feature, while not so clearly pronounced, is found to exist also in Pb1?x SnxTe1?x Sex alloys (x≥0.15) with an off-center tin impurity. An analysis of the possible origins of this effect suggests that, at low temperatures, the Lorentz numbers L of the materials under study are smaller than the L0 numbers employed which correspond to the above scattering mechanisms. The cause of the decrease in L is related to electron scattering at two-level systems, a mechanism whose effect grows with increasing electron energy. An analysis of experimental data obtained at high temperatures, as well as on undoped samples with the lowest possible carrier concentrations, yields the values of L for samples with different electron densities. The minimum value L/L0 = 0.75 is obtained for a lightly doped sample at ~130 K. 相似文献