The Experts below are selected from a list of 40407 Experts worldwide ranked by ideXlab platform
Raul A Monsalve - One of the best experts on this subject based on the ideXlab platform.
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calibration of the edges high band Receiver to observe the global 21 cm signature from the epoch of reionization
The Astrophysical Journal, 2017Co-Authors: Raul A Monsalve, A E E Rogers, Judd D Bowman, Thomas J MozdzenAbstract:The EDGES experiment strives to detect the the sky-average brightness temperature from the 21-cm line emitted during the Epoch of Reionization (EoR) in the redshift range 14 & z & 6. To probe this signal, EDGES conducts single-antenna measurements in the frequency range 100- 200 MHz from the Murchison Radioastronomy Observatory in Western Australia. In this paper we describe the current strategy for calibration of the EDGES instrument and, in particular, of its Receiver. The calibration involves measuring accurately modeled passive and active noise sources connected to the Receiver Input in place of the antenna. We model relevant uncertainties that arise during Receiver calibration and propagate them to the calibrated antenna temperature using a Monte Carlo approach. Calibration effects are isolated by assuming that the sky foregrounds and the antenna beam are perfectly known. We find that if five polynomial terms are used to account for calibration systematics, most of the calibration measurements conducted for EDGES produce residuals of 1 mK or less at 95% confidence. The largest residuals are due to uncertainty in the antenna and Receiver reflection coefficients at levels below 20 mK when observing a low-foreground region. These residuals could be reduced by restricting the band to a smaller frequency range motivated by tighter reionization priors. They could also be reduced by 1) improving the accuracy in reflection measurements, especially their phase, 2) decreasing the changes with frequency of the antenna reflection phase, and 3) improving the impedance match at the antenna-Receiver interface. Subject headings: early universe — cosmology: observations — methods: laboratory — methods: statistical
Telescu Mihai - One of the best experts on this subject based on the ideXlab platform.
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Constructive Signal Approximations for Fast Transient Simulation of Coupled Channels
'Institute of Electrical and Electronics Engineers (IEEE)', 2019Co-Authors: Siviero C., Trinchero R., Grivet-talocia S., Stievano S., Signorini G., Telescu MihaiAbstract:International audienceThis paper addresses the problem of fast transient simulation of high-speed coupled channels driven by transceivers that include Transmitter Feed-Forward Equalization (TX-FFE). Practical circuit hardware implementations of such drivers may not be correctly represented by industry standard algorithmic modeling interfaces, which are usually based on ideal digital finite impulse response filters. In particular, slow transients may arise when aggressive FFE is activated and particular switching sequences significantly stress local voltage regulators integrated in the output buffers. In this paper, we model this effect using a constructive hierarchical approximation of the analog waveforms that form a linearized vector Thevenin or Norton representation of the driver. This representation enables the accurate simulation of coupled channels including both differential and common-mode signals. Analog waveforms at the Receiver Input are readily obtained by standard time-frequency transformations, while including channel characteristics and any additional linear equalization block, if present. This proposed framework is compatible with industry-standard Algorithmic Modeling Interfaces (AMI), extending their scope to coupled channels with non-ideal TX-FFE circuit blocks. Eye diagrams and transient waveforms corresponding to millions of bits are computed in few seconds using a non-optimized software implementation. Random jitter and crosstalk are seemlessly included as in standard AMI frameworks. The results of various numerical experiments on commercial transceivers are reported in this paper, confirming both the accuracy and the efficiency of the proposed framework
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Constructive Signal Approximations for Fast Transient Simulation of Coupled Channels
'Institute of Electrical and Electronics Engineers (IEEE)', 2019Co-Authors: Siviero Claudio, Trinchero Riccardo, Grivet-talocia Stefano, Stievano, Igor S., Signorini Gianni, Telescu MihaiAbstract:This paper addresses the problem of fast transient simulation of high-speed coupled channels driven by transceivers that include Transmitter Feed-Forward Equalization (TX-FFE). Practical circuit hardware implementations of such drivers may not be correctly represented by industry standard algorithmic modeling interfaces, which are usually based on ideal digital finite impulse response filters. In particular, slow transients may arise when aggressive FFE is activated and particular switching sequences significantly stress local voltage regulators integrated in the output buffers. In this paper, we model this effect using a constructive hierarchical approximation of the analog waveforms that form a linearized vector Thevenin or Norton representation of the driver. This representation enables the accurate simulation of coupled channels including both differential and common-mode signals. Analog waveforms at the Receiver Input are readily obtained by standard time-frequency transformations, while including channel characteristics and any additional linear equalization block, if present. This proposed framework is compatible with industry-standard Algorithmic Modeling Interfaces (AMI), extending their scope to coupled channels with non-ideal TX-FFE circuit blocks. Eye diagrams and transient waveforms corresponding to millions of bits are computed in few seconds using a non-optimized software implementation. Random jitter and crosstalk are seemlessly included as in standard AMI frameworks. The results of various numerical experiments on commercial transceivers are reported in this paper, confirming both the accuracy and the efficiency of the proposed framework
Thomas J Mozdzen - One of the best experts on this subject based on the ideXlab platform.
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calibration of the edges high band Receiver to observe the global 21 cm signature from the epoch of reionization
The Astrophysical Journal, 2017Co-Authors: Raul A Monsalve, A E E Rogers, Judd D Bowman, Thomas J MozdzenAbstract:The EDGES experiment strives to detect the the sky-average brightness temperature from the 21-cm line emitted during the Epoch of Reionization (EoR) in the redshift range 14 & z & 6. To probe this signal, EDGES conducts single-antenna measurements in the frequency range 100- 200 MHz from the Murchison Radioastronomy Observatory in Western Australia. In this paper we describe the current strategy for calibration of the EDGES instrument and, in particular, of its Receiver. The calibration involves measuring accurately modeled passive and active noise sources connected to the Receiver Input in place of the antenna. We model relevant uncertainties that arise during Receiver calibration and propagate them to the calibrated antenna temperature using a Monte Carlo approach. Calibration effects are isolated by assuming that the sky foregrounds and the antenna beam are perfectly known. We find that if five polynomial terms are used to account for calibration systematics, most of the calibration measurements conducted for EDGES produce residuals of 1 mK or less at 95% confidence. The largest residuals are due to uncertainty in the antenna and Receiver reflection coefficients at levels below 20 mK when observing a low-foreground region. These residuals could be reduced by restricting the band to a smaller frequency range motivated by tighter reionization priors. They could also be reduced by 1) improving the accuracy in reflection measurements, especially their phase, 2) decreasing the changes with frequency of the antenna reflection phase, and 3) improving the impedance match at the antenna-Receiver interface. Subject headings: early universe — cosmology: observations — methods: laboratory — methods: statistical
Bernhard Hoffschmidt - One of the best experts on this subject based on the ideXlab platform.
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flux density measurement for industrial scale solar power towers
2014Co-Authors: Matthias Offergeld, Hannes Stadler, Marc Röger, Bernhard HoffschmidtAbstract:For separate acceptance tests of a solar power tower’s heliostat field and Receiver, it is necessary to determine the solar flux density distribution over the whole absorber surface. Integrating the flux density delivers the Receiver Input power, which is required for calculating the energy conversion efficiencies of both heliostat field and Receiver. Furthermore, flux density measurement is valuable for supervision and control during operation of a power tower. Flux density at small-scale prototype Receivers has mostly been measured by using a camera and a moving bar so far. The moving bar is a white diffusely reflecting target which is moved quickly through the radiation’s focus in front of the Receiver surface. At the same time, a digital camera cap-tures the radiation reflected off the moving bar, which allows determining the incident flux density. At industrial-scale Receivers though, the installation of a moving bar is hardly feasible due to difficult construction and high costs. Therefore, the development of a measurement method without any mov-ing parts is aspired. For this purpose, the radiation reflected off the absorber itself can be measured in order to calculate the incident flux density [1]. Preliminary work on this method is still immature and has not yet lead to a reliable and satisfying measuring accuracy under all conditions [2]; achieving this is a main aim of the presented thesis. The central challenge with measuring flux density by reflection off the absorber is the absorber’s non-diffusive reflectivity, which depends especially on the direction of the incident radiation as well as on the observation angle [1]. Hence, detailed understanding of reflection at the structured surface of open volumetric Receivers as well as tube Receivers and following software-aided correction of these effects are essential for reducing the measurement uncertainty. The improvements will be imple-mented and tested at the Solar Tower Julich. Finally, the improved flux density measurement system is planned to be used in a demonstrational acceptance testing at the Solar Tower Julich, including a comparison of measurements and simulation results.
Zhaoqing Chen - One of the best experts on this subject based on the ideXlab platform.
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decision feedback equalizer dfe behavioral macro model for packaging system eye diagram transient simulations
Electronic Components and Technology Conference, 2011Co-Authors: Zhaoqing ChenAbstract:Decision Feedback Equalizer (DFE) [1] is widely used in the high-speed packaging system as a part of Receiver for recovering the signal from the distortion by the inter-symbol interference (ISI). Simulating the eye diagram at the Receiver output after DFE is helpful to system designers especially in the case there is no longer an open eye diagram at the Receiver Input. Currently, particular simulation tools or particular algorithm implementations are required to support the modeling and simulation of the DFE function. In this paper, a DFE behavioral macro model is proposed and tested. The proposed DFE behavioral macro model is an HSPICE circuit model and can be used directly in any existing conventional HSPICE compatible transient simulation tools. We use a voltage controlled resistor and a capacitor to model the bit slicer (Symbol Detector) in DFE. The terminated ideal transmission lines with particular delays combined with voltage controlled voltage sources are used for modeling the Feedback Filter (FBF) part of DFE. The summer in DFE is modeled by Directional Junction [2]-[4]. The proposed DFE behavioral macro model can be easily combined directly with existing Receiver behavioral macro models targeting other Receiver behaviors such as the Mpilog Receiver model [5] for accurate Receiver Input property modeling and the hyperbolic — tangent behavioral model[6] for accurate pre-amplifier/CTLE nonlinear modeling.
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Searching for the worst-case eye diagram of a signal channel in electronic packaging system including the effects of the nonlinear I/O devices and the crosstalk from adjacent channels
2009 59th Electronic Components and Technology Conference, 2009Co-Authors: Zhaoqing Chen, George KatopisAbstract:In this paper, we propose a new method for the prediction of the worst case eye diagram for the high performance chip to chip interconnections utilizing SERDES I/O. This method employs transient circuit simulations using an adequate length of all possible bit patterns at the Input of driver, so that the worst-case eye at the Receiver Input can be determined. The signal channels are modeled with multi-port S-parameters. The Mpilog macromodels are used for the I/O devices modeling accurately the nonlinear properties of these devices. The peaks of the crosstalk from adjacent channels are aligned to the worst-case single channel eye diagram for several worst-case scenarios to produce the absolute worst-case eye diagram. The proposed method was applied to the SERDES interconnections of a high-end computer and yielded accurate worst-case eye diagram results with acceptable simulation speed.
