RF Testing on a Mixed Signal Tester

In this paper, testing of radio frequency (RF) devices with mixed-signal testers is discussed. General purpose automatic test equipment (ATE) will be used. In this paper, a more universal test structure utilizing RF building blocks is proposed. A global positioning system (GPS) device is used as an example to illustrate how to develop the RF test plan with this usage. The test plan developed includes fast, cost-effective and dedicated circuitry.

A Transmitter Architecture Based on Delta–Sigma Modulation and Switch-Mode Power Amplification

This brief presents a method of deploying RF switch-mode power amplification for varying envelope signals. Thereby the power amplifier can be operated as a switch with a high power efficiency as the result. The key idea is to transmit either a full RF period or none at all in such a way that the correct modulated RF signal is obtained after filtering. This is accomplished in a novel configuration of a low-pass DeltaSigma modulator using a phase modulated clock combined with a simple AND-gate. The designed modulator is easy to implement, displays very good linearity and offers time domain signals that promote the power efficiency of the power amplifier. The working principle is described through theory and simulations, and validation is done via measurements on a prototype of the modulator. Measurements on the prototype show that the presented modulator modulates a UMTS signal with more than 10-dB margin to the spectrum mask and EVM below 0.85% RMS (req<17.5%). Delta-sigma, power amplifier (PA), RF, switch mode, transmitter architecture, varying envelope.     

UNICORE 6 — Recent and Future Advancements

UNICORE is a European Grid Technology with more than 10 years of history. Originating from the Supercomputing domain, the latest version UNICORE 6 has turned into a general-purpose Grid technology that follows established standards and offers a rich set of features to its users. The paper starts with an architectural insight into UNICORE 6, highlighting the workflow features, standards and the different clients. Next, the current state of advancement is presented by describing recent developments. The paper closes with an outlook on future planned developments.     

A SAED and HREM study of structural defects in brownmillerite,LaBa(x)Sr(1-x)CuGaOy related oxides

The synthesis and microstructural characterization, by means of selected area electron diffraction (SAED) and high resolution electron microscopy (HREM), of the solid solution LaBa(x)Sr(1-x)CuGaO5 (0.1 < or = 5 x < or = 0.9) is reported. Although an average brownmillerite Ima2 structure is proposed for the whole compositional range, SAED and HREM clearly show that structural defects appear as barium content increases.     

Measurement of fractional order model parameters of respiratory mechanical impedance in total liquid ventilation

This study presents a methodology for applying the forced-oscillation technique in total liquid ventilation. It mainly consists of applying sinusoidal volumetric excitation to the respiratory system, and determining the transfer function between the delivered flow rate and resulting airway pressure. The investigated frequency range was f ∈ [0.05, 4] Hz at a constant flow amplitude of 7.5 mL/s. The five parameters of a fractional order lung model, the existing "5-parameter constant-phase model," were identified based on measured impedance spectra. The identification method was validated in silico on computer-generated datasets and the overall process was validated in vitro on a simplified single-compartment mechanical lung model. In vivo data on ten newborn lambs suggested the appropriateness of a fractional-order compliance term to the mechanical impedance to describe the low-frequency behavior of the lung, but did not demonstrate the relevance of a fractional-order inertance term. Typical respiratory system frequency response is presented together with statistical data of the measured in vivo impedance model parameters. This information will be useful for both the design of a robust pressure controller for total liquid ventilators and the monitoring of the patient's respiratory parameters during total liquid ventilation treatment.     

Effets d’un trou métallisé sur les caractéristiques de rayonnement d’une antenne plaque microruban alimentée par une ligne coaxiale à travers le plan de masse

Effects of the via-hole implementation on radiation characteristics of a microstrip patch antenna are computed on an EM resolver based upon integral equations and numerically solved by moment method. Coaxial feed and via-holes are considered as integral parts of the antenna so that after an accurate modeling of the incident field, induced effects of the holes are naturally accounted for. Results show that for some locations, the via-hole effects on the radiation characteristics are negligeable. Such predictions suggest solutions for various problems of practical interest in industrial applications of this new technology.     

Affine-permutation invariance of 2-D shapes.

Shapes provide a rich set of clues on the identity and topological properties of an object. In many imaging environments, however, the same object appears to have different shapes due to distortions such as translation, rotation, reflection, scaling, or skewing. Further, the order by which the object's feature points are scanned changes, i.e., the order of the pixels may be permuted. Relating two-dimensional shapes of the same object distorted by different affine and permutation transformations is a challenge. We introduce a shape invariant that we refer to as the intrinsic shape of an object and describe an algorithm, BLAISER, to recover it. The intrinsic shape is invariant to affine-permutation distortions. It is a uniquely defined representative of the equivalence class of all affine-permutation distortions of the same object. BLAISER computes the intrinsic shape from any arbitrarily affine-permutation distorted image of the object, without prior knowledge regarding the distortions or the undistorted shape of the object. The critical step of BLAISER is the determination of the shape orientation and we provide a detailed discussion on this topic. The operations of BLAISER are based on low-order moments of the input shape and, thus, robust to error and noise. Examples illustrate the performance of the algorithm.     

Dimethylarsine: Pyrolysis mechanisms and use for OMVPE growth

The pyrolysis mechanisms of dimethylarsine (DMAsH) have been studied mass spectrometrically in an atmospheric pressure flow tube reactor. In either the D₂ or He ambient, DMAsH will be converted to trimethylarsine (TMAs) at temperatures of 400–500° via a homogeneous CH₃ radical chain reaction. Supplemental CH₃ radicals, produced from azomethane ((CH₃)₂N₂) pyrolysis, have resulted in a significant increase in the pyrolysis rate for DMAsH. As temperature is increased beyond 500°, the product TMAs will decompose due to hydrogenolysis in D₂ and homolysis in He. At a GaAs surface, DMAsH pyrolyzes heterogeneously. The pyrolysis rate is further accelerated by the addition of trimethylgallium (TMGa). DMAsH has also been combined with TMGa to grow GaAs layers. The as-grown epilayers, at 1 atm and substrate temperatures of 570–720°, are allp-type with the net hole concentration dependent on the carrier gas. The use of N₂ leads to a higher concentration as compared to that in H₂. Photoluminescence spectra have indicated the acceptor to be carbon. A mechanism is developed to interpret these results based on the pyrolysis reactions determined from the kinetic studies.     

A bi-criteria minimum spanning tree routing model for MPLS/overlay networks

The MPLS platform enables the implementation of advanced multipath and multicast routing schemes. This work develops and analyses the performance of a new bi-criteria minimum spanning tree model intended for routing broadcast messages in MPLS networks or constructing tree-based overlay networks. The aim of the model is to obtain spanning trees which are compromise solutions with respect to two important traffic engineering metrics: load balancing cost and average delay bound. An exact solution to the formulated bi-criteria optimization problem is presented, which is based on an algorithm that enables the computation of the set of supported non-dominated spanning trees. An application model and a set of experiments on randomly generated Internet type topologies will also be presented. Finally a network performance analysis of the model considering three network performance metrics will be shown.     

Low overhead assignment of symbolic coordinates in sensor networks

Approximate information on the location of nodes in a sensor network is essential to many types of sensor network applications and algorithms. In many cases, using symbolic coordinates is an attractive alternative to the use of geographic coordinates due to lower costs and lower requirements on the available location information during coordinate assignment. In this paper, we investigate different possible methods of assigning symbolic coordinates to sensor nodes. We present a method based on broadcasting coordinate messages and filtering using sensor events. We show in the evaluation that this method allows a reliable assignment of symbolic coordinates while only generating a low overhead.