7,130 research outputs found
Design and realization of a 2.45 GHz transmitter and receiver as a modular unit for a MIMO SDR
This paper describes a low-cost transmitting and receiving system for wireless communication. In a first part, the design and realization of a transmitter for modulated data at 2.45 GHz carrier frequency and with frequency, amplitude and phase modulation is handled. A second part explains the design and realization of a receiving module, which filters and downconverts the signals to an intermediate frequency. The postprocessing section describes the use of a DVB-T module together with open-source software, SDR#, for the final downconversion, as well as for the demodulation and the detection of the received signals in order to reproduce the originally transmitted data. Combining all components results in a low-cost and flexible software defined radio system
FPSA: A Full System Stack Solution for Reconfigurable ReRAM-based NN Accelerator Architecture
Neural Network (NN) accelerators with emerging ReRAM (resistive random access
memory) technologies have been investigated as one of the promising solutions
to address the \textit{memory wall} challenge, due to the unique capability of
\textit{processing-in-memory} within ReRAM-crossbar-based processing elements
(PEs). However, the high efficiency and high density advantages of ReRAM have
not been fully utilized due to the huge communication demands among PEs and the
overhead of peripheral circuits.
In this paper, we propose a full system stack solution, composed of a
reconfigurable architecture design, Field Programmable Synapse Array (FPSA) and
its software system including neural synthesizer, temporal-to-spatial mapper,
and placement & routing. We highly leverage the software system to make the
hardware design compact and efficient. To satisfy the high-performance
communication demand, we optimize it with a reconfigurable routing architecture
and the placement & routing tool. To improve the computational density, we
greatly simplify the PE circuit with the spiking schema and then adopt neural
synthesizer to enable the high density computation-resources to support
different kinds of NN operations. In addition, we provide spiking memory blocks
(SMBs) and configurable logic blocks (CLBs) in hardware and leverage the
temporal-to-spatial mapper to utilize them to balance the storage and
computation requirements of NN. Owing to the end-to-end software system, we can
efficiently deploy existing deep neural networks to FPSA. Evaluations show
that, compared to one of state-of-the-art ReRAM-based NN accelerators, PRIME,
the computational density of FPSA improves by 31x; for representative NNs, its
inference performance can achieve up to 1000x speedup.Comment: Accepted by ASPLOS 201
Realization and MIMO-link measurements of a transmit module for spatial modulation
This paper describes the realization of a circuit that transmits a data stream, through spatial modulation in the 2.45 GHz frequency band. The development of the transmitter includes RF circuit design with components such as a PLL synthesizer, Tx-DAC and IQ-modulator. A microcontroller, integrated into the circuit and programmed in C, is at the heart of the system.
In this hardware system, developed specifically for spatial modulation, data is BPSK modulated and transmitted through an RF switch connected to two antennas. It can differ for every symbol which antenna is used, according to an extra series of information bits that are to be transmitted. Here the number of the selected antenna encodes the extra information bit per symbol, which not only results in a doubling of the data rate but also realizes diversity. Spatial modulation allows these features with only a single hardware transmit chain, resulting in low-cost and low-complexity hardware. At the receiving side, the extra information bits are decoded by assessing the channel used for each symbol.
This practical system has been thoroughly tested by means of different measuring campaigns. The measurement results show that spatial modulation is correctly demodulated at the receiving side and forms an effective way to realize affordable MIMO systems
Digital frequency domain multiplexing readout electronics for the next generation of millimeter telescopes
Frequency domain multiplexing (fMux) is an established technique for the
readout of transition-edge sensor (TES) bolometers in millimeter-wavelength
astrophysical instrumentation. In fMux, the signals from multiple detectors are
read out on a single pair of wires reducing the total cryogenic thermal loading
as well as the cold component complexity and cost of a system. The current
digital fMux system, in use by POLARBEAR, EBEX, and the South Pole Telescope,
is limited to a multiplexing factor of 16 by the dynamic range of the
Superconducting Quantum Interference Device pre-amplifier and the total system
bandwidth. Increased multiplexing is key for the next generation of large
format TES cameras, such as SPT-3G and POLARBEAR2, which plan to have on the of
order 15,000 detectors.
Here, we present the next generation fMux readout, focusing on the warm
electronics. In this system, the multiplexing factor increases to 64 channels
per module (2 wires) while maintaining low noise levels and detector stability.
This is achieved by increasing the system bandwidth, reducing the dynamic range
requirements though active feedback, and digital synthesis of voltage biases
with a novel polyphase filter algorithm. In addition, a version of the new fMux
readout includes features such as low power consumption and radiation-hard
components making it viable for future space-based millimeter telescopes such
as the LiteBIRD satellite.Comment: 15 pages, 10 figures. To be published in Proceedings of SPIE Volume
9153. Presented at SPIE Astronomical Telescopes + Instrumentation 2014,
conference 915
C-band radar pulse Doppler error: Its discovery, modeling, and elimination
The discovery of a C Band radar pulse Doppler error is discussed and use of the GEOS 3 satellite's coherent transponder to isolate the error source is described. An analysis of the pulse Doppler tracking loop is presented and a mathematical model for the error was developed. Error correction techniques were developed and are described including implementation details
High-speed laser anemometer system for intrarotor flow mapping in turbomachinery
A fringe-type laser anemometer with innovative features is described. The innovative features include: (1) rapid, efficient data acquisition processes, (2) detailed graphic display of data being accumulated, and (3) input laser-beam positioning that allows greater optical access to the intrarotor region. Results are presented that demonstrate the anemometer's capability in flow mapping within a transonic axial-flow compressor rotor
Automatic generation of audio content for open learning resources
This paper describes how digital talking books (DTBs) with embedded functionality for learners can be generated from content structured according to the OU OpenLearn schema. It includes examples showing how a software transformation developed from open source components can be used to remix OpenLearn content, and discusses issues concerning the generation of synthesised speech for educational purposes. Factors which may affect the quality of a learner's experience with open educational audio resources are identified, and in conclusion plans for testing the effect of these factors are outlined
Comparison of input devices in an ISEE direct timbre manipulation task
The representation and manipulation of sound within multimedia systems is an important and currently under-researched area. The paper gives an overview of the authors' work on the direct manipulation of audio information, and describes a solution based upon the navigation of four-dimensional scaled timbre spaces. Three hardware input devices were experimentally evaluated for use in a timbre space navigation task: the Apple Standard Mouse, Gravis Advanced Mousestick II joystick (absolute and relative) and the Nintendo Power Glove. Results show that the usability of these devices significantly affected the efficacy of the system, and that conventional low-cost, low-dimensional devices provided better performance than the low-cost, multidimensional dataglove
Spatial Identification Methods and Systems for RFID Tags
DisertaÄnĂ prĂĄce je zamÄĆena na metody a systĂ©my pro mÄĆenĂ vzdĂĄlenosti a lokalizaci RFID tagĆŻ pracujĂcĂch v pĂĄsmu UHF. Ăvod je vÄnovĂĄn popisu souÄasnĂ©ho stavu vÄdeckĂ©ho poznĂĄnĂ v oblasti RFID prostorovĂ© identifikace a struÄnĂ©mu shrnutĂ problematiky modelovĂĄnĂ a nĂĄvrhu prototypĆŻ tÄchto systĂ©mĆŻ. Po specifikaci cĂlĆŻ disertace pokraÄuje prĂĄce popisem teorie modelovĂĄnĂ degenerovanĂ©ho kanĂĄlu pro RFID komunikaci. DetailnÄ jsou rozebrĂĄny metody mÄĆenĂ vzdĂĄlenosti a odhadu smÄru pĆĂchodu signĂĄlu zaloĆŸenĂ© na zpracovĂĄnĂ fĂĄzovĂ© informace. Pro ĂșÄely lokalizace je navrĆŸeno nÄkolik scĂ©nĂĄĆĆŻ rozmĂstÄnĂ antĂ©n. Modely degenerovanĂ©ho kanĂĄlu jsou simulovĂĄny v systĂ©mu MATLAB. VĂœznamnĂĄ ÄĂĄst tĂ©to prĂĄce je vÄnovĂĄna konceptu softwarovÄ definovanĂ©ho rĂĄdia (SDR) a specifikĆŻm jeho adaptace na UHF RFID, kterĂĄ vyuĆŸitĂ bÄĆŸnĂœch SDR systĂ©mĆŻ znaÄnÄ omezujĂ. DiskutovĂĄna je zejmĂ©na problematika prĆŻniku nosnĂ© vysĂlaÄe do pĆijĂmacĂ cesty a poĆŸadavky na signĂĄl lokĂĄlnĂho oscilĂĄtoru pouĆŸĂvanĂœ pro smÄĆĄovĂĄnĂ. PrezentovĂĄny jsou tĆi vyvinutĂ© prototypy: experimentĂĄlnĂ dotazovaÄ EXIN-1, mÄĆicĂ systĂ©m zaloĆŸenĂœ na platformÄ Ettus USRP a antĂ©nnĂ pĆepĂnacĂ matice pro emulaci SIMO systĂ©mu. ZĂĄvÄreÄnĂĄ ÄĂĄst je zamÄĆena na testovĂĄnĂ a zhodnocenĂ popisovanĂœch lokalizaÄnĂch technik, zaloĆŸenĂœch na mÄĆenĂ komplexnĂ pĆenosovĂ© funkce RFID kanĂĄlu. Popisuje ĂșzkopĂĄsmovĂ©/ĆĄirokopĂĄsmovĂ© mÄĆenĂ vzdĂĄlenosti a metody odhadu smÄru signĂĄlu. Oba navrĆŸenĂ© scĂ©nĂĄĆe rozmĂstÄnĂ antĂ©n jsou v zĂĄvÄru ovÄĆeny lokalizaÄnĂm mÄĆenĂm v reĂĄlnĂœch podmĂnkĂĄch.The doctoral thesis is focused on methods and systems for ranging and localization of RFID tags operating in the UHF band. It begins with a description of the state of the art in the field of RFID positioning with short extension to the area of modeling and prototyping of such systems. After a brief specification of dissertation objectives, the thesis overviews the theory of degenerate channel modeling for RFID communication. Details are given about phase-based ranging and direction of arrival finding methods. Several antenna placement scenarios are proposed for localization purposes. The degenerate channel models are simulated in MATLAB. A significant part of the thesis is devoted to software defined radio (SDR) concept and its adaptation for UHF RFID operation, as it has its specialties which make the usage of standard SDR test equipment very disputable. Transmit carrier leakage into receiver path and requirements on local oscillator signals for mixing are discussed. The development of three experimental prototypes is also presented there: experimental interrogator EXIN-1, measurement system based on Ettus USRP platform, and antenna switching matrix for an emulation of SIMO system. The final part is focused on testing and evaluation of described positioning techniques based on complex backscatter channel transfer function measurement. Both narrowband/wideband ranging and direction of arrival methods are validated. Finally, both proposed antenna placement scenarios are evaluated with real-world measurements.
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