9,667 research outputs found
OCTAD-S: Digital Fast Fourier Transform Spectrometers by FPGA
We have developed a digital fast Fourier transform (FFT) spectrometer made of
an analog-to-digital converter (ADC) and a field-programmable gate array
(FPGA). The base instrument has independent ADC and FPGA modules, which allow
us to implement different spectrometers in a relatively easy manner. Two types
of spectrometers have been instrumented, one with 4.096 GS/s sampling speed and
2048 frequency channels and the other with 2.048 GS/s sampling speed and 32768
frequency channels. The signal processing in these spectrometers has no dead
time and the accumulated spectra are recorded in external media every 8 ms. A
direct sampling spectroscopy up to 8 GHz is achieved by a microwave
track-and-hold circuit, which can reduce the analog receiver in front of the
spectrometer. Highly stable spectroscopy with a wide dynamic range was
demonstrated in a series of laboratory experiments and test observations of
solar radio bursts.Comment: 20 pages, 7 figures, accepted for publication in Earth, Planets and
Spac
SoundCompass: a distributed MEMS microphone array-based sensor for sound source localization
Sound source localization is a well-researched subject with applications ranging from localizing sniper fire in urban battlefields to cataloging wildlife in rural areas. One critical application is the localization of noise pollution sources in urban environments, due to an increasing body of evidence linking noise pollution to adverse effects on human health. Current noise mapping techniques often fail to accurately identify noise pollution sources, because they rely on the interpolation of a limited number of scattered sound sensors. Aiming to produce accurate noise pollution maps, we developed the SoundCompass, a low-cost sound sensor capable of measuring local noise levels and sound field directionality. Our first prototype is composed of a sensor array of 52 Microelectromechanical systems (MEMS) microphones, an inertial measuring unit and a low-power field-programmable gate array (FPGA). This article presents the SoundCompass's hardware and firmware design together with a data fusion technique that exploits the sensing capabilities of the SoundCompass in a wireless sensor network to localize noise pollution sources. Live tests produced a sound source localization accuracy of a few centimeters in a 25-m2 anechoic chamber, while simulation results accurately located up to five broadband sound sources in a 10,000-m2 open field
Steerable optical tweezers for ultracold atom studies
We report on the implementation of an optical tweezer system for controlled
transport of ultracold atoms along a narrow, static confinement channel. The
tweezer system is based on high-efficiency acousto-optical deflectors and
offers two-dimensional control over beam position. This opens up the
possibility for tracking the transport channel when shuttling atomic clouds
along the guide, forestalling atom spilling. Multiple clouds can be tracked
independently by time-shared tweezer beams addressing individual sites in the
channel. The deflectors are controlled using a multichannel direct digital
synthesizer, which receives instructions on a sub-microsecond time scale from a
field-programmable gate array. Using the tweezer system, we demonstrate
sequential binary splitting of an ultracold cloud into
clouds.Comment: 4 pages, 5 figures, 1 movie lin
Neuromorphic, Digital and Quantum Computation with Memory Circuit Elements
Memory effects are ubiquitous in nature and the class of memory circuit
elements - which includes memristors, memcapacitors and meminductors - shows
great potential to understand and simulate the associated fundamental physical
processes. Here, we show that such elements can also be used in electronic
schemes mimicking biologically-inspired computer architectures, performing
digital logic and arithmetic operations, and can expand the capabilities of
certain quantum computation schemes. In particular, we will discuss few
examples where the concept of memory elements is relevant to the realization of
associative memory in neuronal circuits, spike-timing-dependent plasticity of
synapses, digital and field-programmable quantum computing
High Performance Power Spectrum Analysis Using a FPGA Based Reconfigurable Computing Platform
Power-spectrum analysis is an important tool providing critical information
about a signal. The range of applications includes communication-systems to
DNA-sequencing. If there is interference present on a transmitted signal, it
could be due to a natural cause or superimposed forcefully. In the latter case,
its early detection and analysis becomes important. In such situations having a
small observation window, a quick look at power-spectrum can reveal a great
deal of information, including frequency and source of interference. In this
paper, we present our design of a FPGA based reconfigurable platform for high
performance power-spectrum analysis. This allows for the real-time
data-acquisition and processing of samples of the incoming signal in a small
time frame. The processing consists of computation of power, its average and
peak, over a set of input values. This platform sustains simultaneous data
streams on each of the four input channels.Comment: 5 pages, 3 figures. Published in the Proceedings of the IEEE
International conference on Reconfigurable Computing and FPGAs (ReConFig
2006). Article also available at
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4100006&isnumber=409995
A neural probe with up to 966 electrodes and up to 384 configurable channels in 0.13 μm SOI CMOS
In vivo recording of neural action-potential and local-field-potential signals requires the use of high-resolution penetrating probes. Several international initiatives to better understand the brain are driving technology efforts towards maximizing the number of recording sites while minimizing the neural probe dimensions. We designed and fabricated (0.13-μm SOI Al CMOS) a 384-channel configurable neural probe for large-scale in vivo recording of neural signals. Up to 966 selectable active electrodes were integrated along an implantable shank (70 μm wide, 10 mm long, 20 μm thick), achieving a crosstalk of −64.4 dB. The probe base (5 × 9 mm2) implements dual-band recording and a 1
Development and implementation of a LabVIEW based SCADA system for a meshed multi-terminal VSC-HVDC grid scaled platform
This project is oriented to the development of a Supervisory, Control and Data Acquisition
(SCADA) software to control and supervise electrical variables from a scaled platform that
represents a meshed HVDC grid employing National Instruments hardware and LabVIEW logic
environment. The objective is to obtain real time visualization of DC and AC electrical variables
and a lossless data stream acquisition.
The acquisition system hardware elements have been configured, tested and installed on the
grid platform. The system is composed of three chassis, each inside of a VSC terminal cabinet,
with integrated Field-Programmable Gate Arrays (FPGAs), one of them connected via PCI bus
to a local processor and the rest too via Ethernet through a switch. Analogical acquisition
modules were A/D conversion takes place are inserted into the chassis. A personal computer is
used as host, screen terminal and storing space.
There are two main access modes to the FPGAs through the real time system. It has been
implemented a Scan mode VI to monitor all the grid DC signals and a faster FPGA access mode
VI to monitor one converter AC and DC values. The FPGA application consists of two tasks
running at different rates and a FIFO has been implemented to communicate between them
without data loss.
Multiple structures have been tested on the grid platform and evaluated, ensuring the
compliance of previously established specifications, such as sampling and scanning rate, screen
refreshment or possible data loss.
Additionally a turbine emulator was implemented and tested in Labview for further testing
A Scalable Correlator Architecture Based on Modular FPGA Hardware, Reuseable Gateware, and Data Packetization
A new generation of radio telescopes is achieving unprecedented levels of
sensitivity and resolution, as well as increased agility and field-of-view, by
employing high-performance digital signal processing hardware to phase and
correlate large numbers of antennas. The computational demands of these imaging
systems scale in proportion to BMN^2, where B is the signal bandwidth, M is the
number of independent beams, and N is the number of antennas. The
specifications of many new arrays lead to demands in excess of tens of PetaOps
per second.
To meet this challenge, we have developed a general purpose correlator
architecture using standard 10-Gbit Ethernet switches to pass data between
flexible hardware modules containing Field Programmable Gate Array (FPGA)
chips. These chips are programmed using open-source signal processing libraries
we have developed to be flexible, scalable, and chip-independent. This work
reduces the time and cost of implementing a wide range of signal processing
systems, with correlators foremost among them,and facilitates upgrading to new
generations of processing technology. We present several correlator
deployments, including a 16-antenna, 200-MHz bandwidth, 4-bit, full Stokes
parameter application deployed on the Precision Array for Probing the Epoch of
Reionization.Comment: Accepted to Publications of the Astronomy Society of the Pacific. 31
pages. v2: corrected typo, v3: corrected Fig. 1
- …