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DESIGN OF A SOFTWARE RADIO GPS RECEIVERZhengxuan, Zhang, Yanhong, Kou, Qishan, Zhang 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The GPS receiver based on software radio technology is a kind of general purpose GPS signal processing platform which makes use of advanced design ideas and advanced design tools nowadays. We used FPGA device and lots of necessary peripherals such as DSP and PCI controller in our design to promote flexibility and practicability effectively. Various fast acquisition means and accurate tracking algorithms could be realized, improved and validated on this platform, besides basic GPS receiver function.
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Baseband compensation principles for defects in quadrature signal conversion and processingVan Rooyen, Gert-Jan 04 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Keywords: software-defined radio, SDR, quadrature mixing, quadrature modulation, quadrature
demodulation, digital compensation, software radio, direct-digital synthesis, DDS.
An often-stated goal of software-defined transceiver systems is to perform digital signal conversion
as close to the antenna as possible by using high-rate converters. In this dissertation,
alternative design principles are proposed, and it is shown that the signal processing techniques
based on these principles improve on the prior system's accuracy, while maintaining
system flexibility.
Firstly, it is proposed that digital compensation can be used to reverse the effects of
hardware inaccuracies in the RF front-end of a software-defined radio. Novel compensation
techniques are introduced that suppress the signal artefacts introduced by typical frontend
hardware. The extent to which such artefacts may be suppressed, is only limited by the
accuracy by which they may be measured and digitally represented. A general compensation
principle is laid down, which formalises the conditions under which optimal compensation
may be achieved.
Secondly, it is proposed that, in the design of such RF front-ends, a clear distinction
should be drawn between signal processing complexity and frequency translation. It is
demonstrated that conventional SDR systems often neglect this principle. As an alternative,
quadrature mixing is shown to provide a clear separation between the frequency translation
and signal processing problems. However, effective use of quadrature mixing as design approach
necessitates the use of accurate compensation techniques to circumvent the hardware
inaccuracies typically found in such mixers.
Quadrature mixers are proposed as general-purpose front-ends for software-defined radios,
and quadrature modulation and demodulation techniques are presented as alternatives
to existing schemes. The inherent hardware inaccuracies are analysed and simulated, and
appropriate compensation techniques are derived and tested. Finally, the theory is verified
with a prototype system. / AFRIKAANSE OPSOMMING: Sleutelwoorde: sagteware-gedefinieerde radio, SDR, haaksfasige menging, haaksfasige modulasie,
haaksfasige demodulasie, digitale kompensasie, sagteware-radio, direk-digitale sintese,
DDS.
'n Gewilde stelling is dat digitale seinomsetting in sagteware-gedefinieerde kommunikasiestelsels
so na as moontlik aan die antenna moet geskied deur gebruik te maak van hoëspoed
omsetters. Hierdie verhandeling stel alternatiewe ontwerpsbeginsels voor, en toon
aan dat hierdie beginsels die eersgenoemde stelsel se akkuraatheid verbeter, terwyl stelselbuigsaamheid
gehandhaaf word.
Dit word eerstens voorgestel dat digitale kompensasie gebruik word om die effekte van
hardeware-onakkuraathede in die RF-koppelvlak van sagteware-gedefinieerde radio's om te
keer. Nuwe kompensasietegnieke, wat seinartefakte weens koppelvlak-onakkuraathede kan
onderdruk, word aangebied. Die mate waartoe hierdie artefakte onderdruk kan word, word
slegs beperk deur die akkuraatheid waarmee dit gemeet en digitaal voorgestel kan word. 'n
Algemene kompensasiebeginsel word neergelê waarin die voorwaardes vir optimale kompensasie
vasgelê word.
Tweedens word voorgestel dat 'n duidelike onderskeid getref word tussen seinverwerkingskompleksiteit
en seinverskuiwing in RF-koppelvlakke. Daar word getoon dat konvensionele
SDR-stelsels dikwels nie hierdie beginsel handhaaf nie. 'n Alternatief, naamlik haaksfasige
menging, word voorgehou as 'n tegniek wat duidelik onderskei tussen seinverskuiwing en
seinverwerking. Akkurate kompensasietegnieke is egter nodig om effektief van sulke mengers
gebruik te maak.
Haaksfasige mengers word voorgestel as veeldoelige koppelvlakke vir sagteware-gedefinieerde
radio's, en haaksfasige modulasie- en demodulasietegnieke word voorgestel as plaasvervangers
vir bestaande tegnieke. Die inherente hardeware-onakkuraathede word geanaliseer
en gesimuleer, en geskikte kompensasietegnieke word afgelei en getoets. Laastens word die
teoretiese resultate met 'n praktiese prototipe bevestig.
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Software modem for a software defined radio systemSmuts, Matthys 03 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / The use of older and slower protocols has become increasingly difficult to justify due to
the rapid pace at which telecommunications are advancing. To keep up to date with the
latest technologies, the communications system must be designed to accommodate the
transparent insertion of new communications standards in all the stages of a system. The
system should, however, also remain compatible with the older standards so as not to
demand an upgrade of the older systems.
The concept of a software defined radio was introduced to overcome these problems. In
a software defined radio system, the functionality of the communications system is defined
in software, which removes the the need for alterations to the hardware during technology
upgrade. To maintain interoperatibilty, the system must be based on a standardised
architecture. This would further allow for enhanced scalability and provide a plug-andplay
feature for the components of the system.
In this thesis, generic signal processing software components are developed to illustrate
the creation of a basic software modem that can be parameterised to comply fully, or
partially, to various standards.
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A Cross Platform Framework for Software Defined RadioBrady, Richard 12 1900 (has links)
Thesis (MScEng (Electical and Electronic Engineering))--University of Stellenbosch, 2007. / Software defined radios (SDRs) implement in software those parts of a radio which have
traditionally been implemented in analogue hardware. We explain the importance of this
definition and introduce reconfigurability and portability as two further goals. Reconfigurabilty
is a property of the SDR platform, which may be a microprocessor, configurable
hardware device, or combination of the two. We demonstrate that the field-programmable
gate array is suficient for the implementation of practical SDR systems. Portability, on the
other hand, is a property of the modulation and demodulation software, also known as waveform
specification software. We evaluate techniques for achieving portability and show that
waveforms can be specified in a generic form suitable for the autogeneration of implementations
targetting both microprocessor- and FPGA-based architectures. The generated code
is in C++ and VHDL respectively, and the tools used include formal models of computation
and the XSLT language.
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A software-defined radio implementation of maritime AISMathapo, Kgabo Frans 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / SumbandilaSat is the second South African satellite, and is scheduled to be launched in
April/May 2007. A software defined radio (SDR) automatic identification system (AIS)
receiver is proposed as a possible experimental payload for this satellite. The AIS receiver can
be used to track and store movement of ships at sea, and then forward this information to the
ground station upon request. This thesis demonstrates the design of a SDR AIS receiver for
Sumbandila satellite. The design of a GMSK/FMmodem as used in AIS is presented. Models
are developed and simulated in Matlab. Digital signal processing algorithms developed for
the AIS receiver are highlighted. Algorithms are developed to decode and translate the AIS
encapsulated binary messages. The models are transferred to C++ and the AIS receiver is
implemented on the SDR architecture. Finally the real time performance of the AIS receiver
is presented along with some test results and performance analysis.
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Automatic compensation for inaccuracies in quadrature mixersStormyrbakken, Christer 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2005. / In an ideal software defined radio (SDR), all parameters are defined in software, which
means the radio can be reconfigured to handle any communications standard. A major
technical challenge that needs to be overcome before this SDR can be realised, is the
design of an RF front end that can convert any digital signal to an analogue signal at any
carrier frequency and vice versa. Quadrature mixing (QM) can be used to implement and
analogue front end, that performs up and down conversion between the complex
baseband centred around 0 Hz and the carrier frequency. By separating the tasks of
frequency conversion and digital-to-analogue conversion, the latter can be performed at a
much lower sample rate, greatly reducing the demands on the hardware. Furthermore, as
QM can handle variable carrier frequency and signal bandwidth, this can be done without
sacrificing reconfigurability. Using QM as an analogue front end may therefore be the
solution to implementing SDR handsets.
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Orthogonal frequency division multiplexing (OFDM) implementation as part of a software devined radio (SDR) environmentSonntag, Christoph 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2005. / Orthogonal Frequency Division Multiplexing (ODFM) has gained considerable attention the past couple of years. In our modern world the need for faster data transmission is never-ending. OFDM modulation provides us with a way of more densely packing modulated carriers in the frequency domain than other existing Frequency Multiplexing schemes, thus achieving higher data rates through communications channels.
Software Defined Radio (SDR) creates a very good entry point for designing any communications system. SDR is an architecture that aims to minimise hardware components in electronic communications circuits by doing all possible processing in the software domain. Such systems have many advantages over existing hardware implementations and can be executed on various platforms and embedded systems, given that the appropriate analogue front ends are attached to the system.
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Benefits to processor load for quadrature baseband versus radio frequency demodulation algorithmsNdovi, Lusungu 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. / The continued advancement and improvement of software-defined radio technology has
been a key factor in furthering research into the implementation of most signal
processing algorithms at baseband. Traditionally, these algorithms have been carried
out at RF, but with the coming of SDR, there has been a need to shift the processing
down to baseband frequencies which are more compatible with the fast developing
software radio technology.
The study looks at selected demodulation algorithms and investigates the
possibility and benefits of carrying them out at QBB. The study ventures into the area
of beamforming, multipath compensation, Doppler shift compensation and matched
filter detection. The analysis is carried out using Matlab simulations at RF and QBB.
The results obtained are compared, not only to evaluate the possibility but also the
benefits in terms of the processing load. The results of the study showed that indeed,
carrying out the selected demodulation algorithms at QBB was not only possible, but
also resulted in an improvement in the processing speed brought about by the reduction
in the processing load.
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DAB implementation in SDR / Digital audio broadcasting in software defined radioErnest, Petro Pesha 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2005. / The aim of this thesis is to implement a Digital Audio Broadcasting (DAB) system in a Software
Defined Radio (SDR). The physical modulation part of the DAB transmitter for one of the
transmission modes as well as its receiver is to be implemented and tested in the SDR. DAB
transmission mode II is implemented.
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Contribution à l’étude et à la réalisation d’un frontal radiofréquence analogique en temps discrets pour la radio-logicielle intégraleRivet, François 19 June 2009 (has links)
Le concept de Radio Logicielle propose d’intégrer en un seul circuit un émetteur / récepteur RF capable d’émettre et de recevoir n’importe quel signal RF. Cependant, ce concept doit a?ronter des contraintes technologiques dans le cas des terminaux mobiles. La contrainte principale est la consommation de puissance du terminal. En e?et, la conversion analogique numérique qui est la clé de ce système en est aussi le principal verrou technique. Cette thèse présente une architecture de récepteur en rupture avec les architectures classiques a?n de surmonter le problème de la conversion analogique numérique. Il s’agit d’un processeur analogique de traitement du signal dédié à la Radio Logicielle intégrale dans la gamme de fréquence 0 à 5GHz. Sa conception et les mesures d’un prototype sont présentées. / Many technological bottlenecks prevent from realizing a Software Radio (SR) mobile terminal. The old way of building radio architectures is over due to the numerous communication standards a single handeld terminal have to address nowadays. This thesis exposes a disruptive SR receiver: a Sampled Analog Signal Processor (SASP) is designed and brought into play to perform downconversion and channel presort. It processes analog voltage samples in order to recover in baseband any RF signal emitted from 0 to 5GHz. An analog Fast Fourier Transform achieves both frequency shifting and ?ltering. A prototype using 65nm CMOS technology from STMicroelectronics is here presented and measured.
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