12,305 research outputs found
The Murchison Widefield Array: Design Overview
The Murchison Widefield Array (MWA) is a dipole-based aperture array
synthesis telescope designed to operate in the 80-300 MHz frequency range. It
is capable of a wide range of science investigations, but is initially focused
on three key science projects. These are detection and characterization of
3-dimensional brightness temperature fluctuations in the 21cm line of neutral
hydrogen during the Epoch of Reionization (EoR) at redshifts from 6 to 10,
solar imaging and remote sensing of the inner heliosphere via propagation
effects on signals from distant background sources,and high-sensitivity
exploration of the variable radio sky. The array design features 8192
dual-polarization broad-band active dipoles, arranged into 512 tiles comprising
16 dipoles each. The tiles are quasi-randomly distributed over an aperture
1.5km in diameter, with a small number of outliers extending to 3km. All
tile-tile baselines are correlated in custom FPGA-based hardware, yielding a
Nyquist-sampled instantaneous monochromatic uv coverage and unprecedented point
spread function (PSF) quality. The correlated data are calibrated in real time
using novel position-dependent self-calibration algorithms. The array is
located in the Murchison region of outback Western Australia. This region is
characterized by extremely low population density and a superbly radio-quiet
environment,allowing full exploitation of the instrumental capabilities.Comment: 9 pages, 5 figures, 1 table. Accepted for publication in Proceedings
of the IEE
Current and Nascent SETI Instruments
Here we describe our ongoing efforts to develop high-performance and
sensitive instrumentation for use in the search for extra-terrestrial
intelligence (SETI). These efforts include our recently deployed Search for
Extraterrestrial Emissions from Nearby Developed Intelligent Populations
Spectrometer (SERENDIP V.v) and two instruments currently under development;
the Heterogeneous Radio SETI Spectrometer (HRSS) for SETI observations in the
radio spectrum and the Optical SETI Fast Photometer (OSFP) for SETI
observations in the optical band. We will discuss the basic SERENDIP V.v
instrument design and initial analysis methodology, along with instrument
architectures and observation strategies for OSFP and HRSS. In addition, we
will demonstrate how these instruments may be built using low-cost, modular
components and programmed and operated by students using common languages, e.g.
ANSI C.Comment: 12 pages, 5 figures, Original version appears as Chapter 2 in "The
Proceedings of SETI Sessions at the 2010 Astrobiology Science Conference:
Communication with Extraterrestrial Intelligence (CETI)," Douglas A. Vakoch,
Edito
Optimization of multi-gigabit transceivers for high speed data communication links in HEP Experiments
The scheme of the data acquisition (DAQ) architecture in High Energy Physics
(HEP) experiments consist of data transport from the front-end electronics
(FEE) of the online detectors to the readout units (RU), which perform online
processing of the data, and then to the data storage for offline analysis. With
major upgrades of the Large Hadron Collider (LHC) experiments at CERN, the data
transmission rates in the DAQ systems are expected to reach a few TB/sec within
the next few years. These high rates are normally associated with the increase
in the high-frequency losses, which lead to distortion in the detected signal
and degradation of signal integrity. To address this, we have developed an
optimization technique of the multi-gigabit transceiver (MGT) and implemented
it on the state-of-the-art 20nm Arria-10 FPGA manufactured by Intel Inc. The
setup has been validated for three available high-speed data transmission
protocols, namely, GBT, TTC-PON and 10 Gbps Ethernet. The improvement in the
signal integrity is gauged by two metrics, the Bit Error Rate (BER) and the Eye
Diagram. It is observed that the technique improves the signal integrity and
reduces BER. The test results and the improvements in the metrics of signal
integrity for different link speeds are presented and discussed
Spike-based VITE control with Dynamic Vision Sensor applied to an Arm Robot.
Spike-based motor control is very important in the
field of robotics and also for the neuromorphic engineering
community to bridge the gap between sensing / processing
devices and motor control without losing the spike philosophy
that enhances speed response and reduces power consumption.
This paper shows an accurate neuro-inspired spike-based system
composed of a DVS retina, a visual processing system that detects
and tracks objects, and a SVITE motor control, where everything
follows the spike-based philosophy. The control system is a spike
version of the neuroinspired open loop VITE control algorithm
implemented in a couple of FPGA boards: the first one runs the
algorithm and the second one drives the motors with spikes. The
robotic platform is a low cost arm with four degrees of freedom.Ministerio de Ciencia e Innovación TEC2009-10639-C04-02/01Ministerio de Economía y Competitividad TEC2012-37868-C04-02/0
Electronics and data acquisition demonstrator for a kinetic inductance camera
A prototype of digital frequency multiplexing electronics allowing the real
time monitoring of kinetic inductance detector (KIDs) arrays for mm-wave
astronomy has been developed. It requires only 2 coaxial cables for
instrumenting a large array. For that, an excitation comb of frequencies is
generated and fed through the detector. The direct frequency synthesis and the
data acquisition relies heavily on a large FPGA using parallelized and
pipelined processing. The prototype can instrument 128 resonators (pixels) over
a bandwidth of 125 MHz. This paper describes the technical solution chosen, the
algorithm used and the results obtained
Digital Complex Correlator for a C-band Polarimetry survey
The international Galactic Emission Mapping project aims to map and
characterize the polarization field of the Milky Way. In Portugal it will
cartograph the C-band sky polarized emission of the Northern Hemisphere and
provide templates for map calibration and foreground control of microwave space
probes like ESA Planck Surveyor mission. The receiver system is equipped with a
novel receiver with a full digital back-end using an Altera Field Programmable
Gate Array, having a very favorable cost/performance relation. This new digital
backend comprises a base-band complex cross-correlator outputting the four
Stokes parameters of the incoming polarized radiation. In this document we
describe the design and implementation of the complex correlator using COTS
components and a processing FPGA, detailing the method applied in the several
algorithm stages and suitable for large sky area surveys.Comment: 15 pages, 10 figures; submitted to Experimental Astronomy, Springe
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