Digital Offset Calibration of an OPAMP Towards Improving Static Parameters of 90 nm CMOS DAC

In this paper, an on-chip self-calibrated 8-bit R-2R digital-to-analog converter (DAC) based on digitally compensated input offset of the operational amplifier (OPAMP) is presented. To improve the overall DAC performance, a digital offset cancellation method was used to compensate deviations in the input offset voltage of the OPAMP caused by process variations. The whole DAC as well as offset compensation circuitry were designed in a standard 90 nm CMOS process. The achieved results show that after the self-calibration process, the improvement of 48% in the value of DAC offset error is achieved

Problem of Bundled Two-Wire Cable of Tested Equipment in Emission Measurement

Many factors that influence radiated emission measurement exist. Except of factors relative to measuring chain \"test site - antenna - receiver\" there are some factors caused by operating personnel like inappropriate configuration of tested equipment, etc. Tested equipments contain generally attached cables of different length; the longer ones shall be shortened by folding into a bundle. The aim of this paper is to analyze the behavior of such cables and its influence on results of radiated emission measurement

Proučavanje sekundarne rekristalizacije u čeliku s orijentiranim zrnima pri dinamičkim uvjetima toplinske obradbe

The present study was made to investigate secondary recrystallization in grain-oriented steels annealed at short time temperature exposures with application of dynamical heating. The investigated GO steels for experiments were taken from one industrial line after final cold rolling reduction and subsequent box annealing. It was shown that application of short time heat treatment conditions could lead to complete abnormal grain growth in the investigated GO steel. The texture and microstructure obtained in the laboratory treated material is similar to that observed in the same GO steel taken after industrial final box-annealing. However, some “parasitic” grains were observed in the secondary recrystallized matrix of the laboratory treated GO steel. These “parasitic” grains possess the unwanted from magnetic properties point of view {111} orientation components.Ova studija istražuje sekundarnu rekristalizaciju u čelicima s orijentiranim zrnima odžarenim kratkotrajno, a pod utjecajem dinamičkog zagrijavanja. Istraživanja ZO čelika za eksperimente uzeti su iz jedne industrijske linije nakon konačnog hladnog redukcijskog valjanja i naknadnog žarenja u komori. Pokazano je, primjena uvjeta kratkotrajne toplinske obradbe mogu dovesti do potpuno nenormalnog rasta zrna u istraživanom ZO čeliku. Tekstura i dobivena mikrostruktura u laboratorijski obrađivanim materijalima, slični su onim primjećenih kod nekih ZO čelika uzetih nakon konačnog industrijskog žarenja u komori. Međutim, neka „parazitna“ zrna primjećena su tijekom sekundarne rekristalizacije laboratorijski tretiranih ZO čelika. Ova „parazitna“ zrna posjeduju nepoželjne (111) orijentirane komponente s točke gledišta magnetnih svojstava

Učinak druge faze topologije čestica pri početnoj temperaturi abnormalnog rasta zrna kod Fe – 3% Si čelika

The relations between regimes of dynamic annealing, state of secondary particles system and the onset temperature of abnormal grain growth are investigated. Two distinguish types of Fe-3%Si grain-oriented steels, after one and two stage cold rolling, were studied. The second phase particles remain unaffected in first type of steel during the heat treatment. Vice versa, the increased density of second phases was observed after annealing in the second type of the investigated materials. It is shown that start/onset of abnormal grain growth strongly depends on both volume fraction of second phase particles and annealing temperature. Texture and magnetic properties of the investigated samples are investigated within the current study.Istraživani su odnosi između režima dinamičkog žarenja, stanja sustava sekundarnih čestica i početne temperature abnormalnog rasta zrna. Analizirane su dvije različite vrste Fe-3%Si zrnato usmjerenih čelika, nakon prve i druge faze hladnog valjanja. Čestice druge faze ostaju nepromijenjene kod prve vrste čelika tijekom toplinske obrade. Obrnuto, uočena je povećana gustoća u drugoj fazi nakon žarenja kod druge vrste ispitanih materijala. Prikazano je da početak abnormalnog rasta zrna uvelike ovisi i o opsegu čestica druge faze i o temperaturi žarenja. Ova analiza istražuje teksturu i magnetska svojstva ispitanih uzoraka

Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities

The current-induced spin polarization and momentum-dependent spin-orbit field were measured in In$_{x}$Ga$_{1-x}$As epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbit coupling, are found to qualitatively agree with the experimental results.Comment: 16 pages, 8 figure

A Millimeter-wave Galactic Plane Survey with the BICEP Polarimeter

In order to study inflationary cosmology and the Milky Way Galaxy's composition and magnetic field structure, Stokes I, Q, and U maps of the Galactic plane covering the Galactic longitude range 260° < ℓ < 340° in three atmospheric transmission windows centered on 100, 150, and 220 GHz are presented. The maps sample an optical depth 1 ≾ AV ≾ 30, and are consistent with previous characterizations of the Galactic millimeter-wave frequency spectrum and the large-scale magnetic field structure permeating the interstellar medium. The polarization angles in all three bands are generally perpendicular to those measured by starlight polarimetry as expected and show changes in the structure of the Galactic magnetic field on the scale of 60°. The frequency spectrum of degree-scale Galactic emission is plotted between 23 and 220 GHz (including WMAP data) and is fit to a two-component (synchrotron and dust) model showing that the higher frequency BICEP data are necessary to tightly constrain the amplitude and spectral index of Galactic dust. Polarized emission is detected over the entire region within two degrees of the Galactic plane, indicating the large-scale magnetic field is oriented parallel to the plane of the Galaxy. A trend of decreasing polarization fraction with increasing total intensity is observed, ruling out the simplest model of a constant Galactic magnetic field orientation along the line of sight in the Galactic plane. A generally increasing trend of polarization fraction with electromagnetic frequency is found, varying from 0.5%-1.5% at frequencies below 50 GHz to 2.5%-3.5% above 90 GHz. The effort to extend the capabilities of BICEP by installing 220 GHz band hardware is described along with analysis of the new band