Software Defined Radio using MATLAB & Simulink and the RTL-SDR

The availability of the RTL-SDR for less than $20 brings SDR to the home and work desktops of EE students, professional engineers and the maker community. The RTL-SDR device can be used to acquire and sample RF (radio frequency) signals transmitted in the frequency range 25MHz to 1.75GHz, and using some official software add-ons, these samples can be brought into the MATLAB and Simulink environment for users to develop receivers using first principles DSP algorithms. Signals that the RTL-SDR hardware can receive include: FM radio, UHF band signals, ISM signals, GSM, 3G and LTE mobile radio, GPS and satellite signals, and any that the reader can (legally) transmit of course! In this free book we introduce readers to SDR methods by viewing and analysing downconverted RF signals in the time and frequency domains, and then provide extensive DSP enabled SDR design exercises which the reader can learn from. The hands-on examples begin with simple AM and FM receivers, and move on to the more challenging aspects of PHY layer DSP, where receive filter chains, real-time channelisers, and advanced concepts such as carrier synchronisers, digital PLL designs and QPSK timing and phase synchronisers are implemented. Towards the end of the book, we demonstrate how the RTL-SDR can be used with SDR transmitters to develop a more complete communications system, capable of transmitting text strings and images across the desktop

Implementation ;performance investigation of dicode PPM over dispersive optical channels

This work is concerned with the development and investigation of a Dicode PPM (DiPPM) system. A DiPPM coder was developed to code any input PCM signal into DiPPM format. A further investigation took place on the DiPPM spectrum and associated output. Software simulation and mathematical analysis of this PPM code was considered and comparison with previous theoretical results presented. Results show that DiPPM is an advantageous PPM code for optic communication; DiPPM spectrum is not concentrated near to DC and it is possible to extract the DiPPM framerate component directly from the pulse stream. A timing extraction circuit that recovers the clock from a DiPPM sequence and synchronises the slots within the frames, was constructed successfully. This enabled transmission through fibre optics and Free Space Optics (FSO). The technique used for the timing extraction circuit of the DiPPM scheme gives an advantage over many of the PPM formats. An optical transmitter/receiver system was developed and the DiPPM scheme was investigated through optical channels. Results show that the DiPPM sequence transferred through the optic system was not changed and the clock had been recovered. A DiPPM decoder was constructed and the received DiPPM signal returned to its original PCM form without errors. Both DiPPM coder and decoder were developed in VHDL and measurements were taken. The timing extraction was programmed in VHDLAMS with the use of digital, analogue and mathematical equations. DiPPM MLSD was also constructed in VHDL. Simulation results proved the theoretical expectations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Optimisation des performances de réseaux de capteurs dynamiques par le contrôle de synchronisation dans les systèmes ultra large bande

The basic concept of Impulse-Radio UWB (IR-UWB) technology is to transmit and receive baseband impulse waveform streams of very low power density and ultra-short duration pulses (typically at nanosecond scale). These properties of UWB give rise to fine time-domain resolution, rich multipath diversity, low power and low cost on-chip implementation facility, high secure and safety, enhanced penetration capability, high user capacity, and potential spectrum compatibility with existing narrowband systems. Due to all these features, UWB technology has been considered as a feasible technology for WSN applications. While UWB has many reasons to make it a useful and exciting technology for wireless sensor networks and many other applications, it also has some challenges which must be overcome for it to become a popular approach, such as interference from other UWB users, accurate modelling of the UWB channel in various environments, wideband RF component (antennas, low noise amplifiers) designs, accurate synchronization, high sampling rate for digital implementations, and so on. In this thesis, we will focus only on one of the most critical issues in ultra wideband systems: Timing Synchronization.Dans cette thèse nous nous sommes principalement concentrés sur les transmissions impulsion radio Ultra Large Bande (UWB-IR) qui a plusieurs avantages grâce à la nature de sa bande très large (entre 3.1GHZ et 10.6GHz) qui permet un débit élevé et une très bonne résolution temporelle. Ainsi, la très courte durée des impulsions émises assure une transmission robuste dans un canal multi-trajets dense. Enfin la faible densité spectrale de puissance du signal permet au système UWB de coexister avec les applications existantes. En raison de toutes ces caractéristiques, la technologie UWB a été considérée comme une technologie prometteuse pour les applications WSN. Cependant, il existe plusieurs défis technologiques pour l'implémentation des systèmes UWB. A savoir, une distorsion différente de la forme d'onde du signal reçu pour chaque trajet, la conception d'antennes très larges bandes de petites dimensions et non coûteuses, la synchronisation d'un signal impulsionnel, l'utilisation de modulation d'onde d'ordre élevé pour améliorer le débit etc. Dans ce travail, Nous allons nous intéresser à l'étude et l'amélioration de la synchronisation temporelle dans les systèmes ULB

The Fifth NASA Symposium on VLSI Design

The fifth annual NASA Symposium on VLSI Design had 13 sessions including Radiation Effects, Architectures, Mixed Signal, Design Techniques, Fault Testing, Synthesis, Signal Processing, and other Featured Presentations. The symposium provides insights into developments in VLSI and digital systems which can be used to increase data systems performance. The presentations share insights into next generation advances that will serve as a basis for future VLSI design

The application of aperture synthesis techniques to satellite radar altimetry

Radar altimetry over the ocean is now a well established discipline of satellite remote sensing, providing measurements of mean height, significant waveheight and surface wind speed. In contrast, radar altimetry over non-ocean surfaces, to obtain topography of land and polar ice sheets, is still a new idea. The difference between these two situations is that the ocean surface is essentially flat with a very small vertical extent, so a broad-beam pulse-limited mode radar altimeter having a relatively small antenna is sufficient to give very accurate measurements of the ocean mean height. However for topographic surfaces, variations in the elevation can be much higher, and using a conventional altimeter causes serious problems, such as interpretation error and misregistration of a measured range, which cannot be normally corrected. To avoid these problems, a considerably narrower beam antenna has to be used to localise the surface under observation. This requires very large antenna structures, which would be both complex and costly. This thesis investigates the application of aperture synthesis techniques to narrow-beam altimetry as an alternative to physically large antennas, to achieve high along-track resolution. It considers the analysis of the involved factors and design parameters, errors, data handling and signal processing requirements and methods for fixing the antenna beam accurately with the ultimate goal of providing a dynamic global altimetric database. In the second half of the thesis, an experimental aircraft-borne altimeter is examined. Details of the design, construction and evaluation of a prototype system are described. This radar includes several novel features, such as aperture synthesis with full-deramp range processing, digital chirp generation, bistatic FMCW operation and off-line digital signal processing. Also a series of experiments are arranged for this radar to examine its performance to process the signature of corner reflector targets, and consideration is given to the extension of these ideas to a satellite-borne instrument