Developing Model-Based Design Evaluation for Pipelined A/D Converters

This paper deals with a prospective approach of modeling, design evaluation and error determination applied to pipelined A/D converter architecture. In contrast with conventional ADC modeling algorithms targeted to extract the maximum ADC non-linearity error, the innovative approach presented allows to decompose magnitudes of individual error sources from a measured or simulated response of an ADC device. Design Evaluation methodology was successfully applied to Nyquist rate cyclic converters in our works [13]. Now, we extend its principles to pipelined architecture. This qualitative decomposition can significantly contribute to the ADC calibration procedure performed on the production line in term of integral and differential nonlinearity. This is backgrounded by the fact that the knowledge of ADC performance contributors provided by the proposed method helps to adjust the values of on-chip converter components so as to equalize (and possibly minimize) the total non-linearity error. In this paper, the design evaluation procedure is demonstrated on a system design example of pipelined A/D converter. Significant simulation results of each stage of the design evaluation process are given, starting from the INL performance extraction proceeded in a powerful Virtual Testing Environment implemented in Maple™ software and finishing by an error source simulation, modeling of pipelined ADC structure and determination of error source contribution, suitable for a generic process flow

Do primary energy resources influence industry location?

By choosing to locate in a particular place, firms create employment opportunities for workers living there. And the wages they pay increase demand for local goods and services, creating additional job opportunities and further increasing the tax base. Consequently, state and local governments go to great lengths to encourage firms to locate within their boundaries.> In recent years, volatility in energy markets due to deregulation and events in the Middle East have increased the role that energy resource endowments may play in firm location. Thus, economic development agencies in energy producing states have highlighted their natural advantages as a way to attract and retain businesses. Yet there is scant evidence that firms base their location decisions on the availability of primary energy resources, such as coal, oil, and natural gas.> Martinek and Orlando explore the role of primary energy resources in industry location. They examine the relationship between state energy supplies and employment in energy-intensive industries and suggest there is a limited relationship between the production of primary energy resources and industry location. State energy supplies are associated with the location of only the most energy-intensive firms. In other energy-intensive industries, firm location decisions appear largely unresponsive to state energy conditions.Industrial location ; Natural resources ; Employment (Economic theory)

Biquad Based on a Generalized Divider Structure

The paper deals with the biquad based on a generalized divider structure. This principle can be considered as an effective way of universal filter and equalizers synthesis, which easily realizes any general transfer function. An attention is devoted to the derivation of optimum design conditions. As shown, these conditions strongly depend on the amplifier type used. The results obtained are illustrated by some design examples

Employment growth mixed across Eighth District

Employment ; Federal Reserve District, 8th

Eighth District population growth follows national pattern

Federal Reserve District, 8th ; Population

The Two-impurity Anderson Model Revisited: Competition between Kondo Effect and Reservoir-mediated Superexchange in Double Quantum Dots

We study a series-coupled double quantum dot in the Kondo regime modeled by the two-impurity Anderson model and find a new conduction-band mediated superexchange interaction that competes with Kondo physics in the strong Coulomb interaction limit. Our numerical renormalization group results, complemented with the higher-order Rayleigh-Schr\"odinger perturbation theory, show that the novel exchange mechanism leads to clear experimental consequences that can be checked in transport measurements through double quantum dots

Electric-field controlled spin reversal in a quantum dot with ferromagnetic contacts

Manipulation of the spin-states of a quantum dot by purely electrical means is a highly desirable property of fundamental importance for the development of spintronic devices such as spin-filters, spin-transistors and single-spin memory as well as for solid-state qubits. An electrically gated quantum dot in the Coulomb blockade regime can be tuned to hold a single unpaired spin-1/2, which is routinely spin-polarized by an applied magnetic field. Using ferromagnetic electrodes, however, the properties of the quantum dot become directly spin-dependent and it has been demonstrated that the ferromagnetic electrodes induce a local exchange-field which polarizes the localized spin in the absence of any external fields. Here we report on the experimental realization of this tunneling-induced spin-splitting in a carbon nanotube quantum dot coupled to ferromagnetic nickel-electrodes. We study the intermediate coupling regime in which single-electron states remain well defined, but with sufficiently good tunnel-contacts to give rise to a sizable exchange-field. Since charge transport in this regime is dominated by the Kondo-effect, we can utilize this sharp many-body resonance to read off the local spin-polarization from the measured bias-spectroscopy. We show that the exchange-field can be compensated by an external magnetic field, thus restoring a zero-bias Kondo-resonance, and we demonstrate that the exchange-field itself, and hence the local spin-polarization, can be tuned and reversed merely by tuning the gate-voltage. This demonstrates a very direct electrical control over the spin-state of a quantum dot which, in contrast to an applied magnetic field, allows for rapid spin-reversal with a very localized addressing.Comment: 19 pages, 11 figure