Widely Tunable RF Frontend for the Universal Software Radio Peripheral: the MMP9000

This report presents the design and construction of a wideband transceiver in the context of an RF frontend for a software radio development platform, the Universal Software Radio Peripheral (USRP). This daughterboard is designed to operate at either full or half duplex modes over a frequency range of 100 MHz to 1.3 GHz or greater. It is fully integrated with both the USRP and GNU Radio, a free software radio development toolkit, to fully control the daughterboard via software

Development of an integrated silicon photonic transceiver for access networks

Debido a la imparable aparición de dispositivos móviles multifunción junto con aplicaciones que requieren cada vez más un mayor ancho de banda en cualquier momento y en cualquier lugar, las futuras redes de acceso deberán ser capaces de proporcionar servicios tanto inalámbricos como cableados. Es por ello que una solución a seguir es el uso de sistemas de comunicaciones ópticas como medio de transporte de señales inalámbricas en enlaces de radio sobre fibra. Con ello, se converge a un dominio óptico reduciendo y aliviando el cuello de botella entre los estándares de acceso inalámbrico y cableado. En esta tesis, como parte de los objetivos establecidos en el proyecto europeo HELIOS en el que está enmarcada, se han investigado y desarrollado los bloques funcionales básicos necesarios para realizar un transceptor fotónico integrado trabajando en el rango de longitudes de onda milimétricas, y haciendo uso de los formatos de modulación más robustos y que mejor se adaptan al ámbito de aplicación considerado. El trabajo que se presenta en esta tesis se puede dividir básicamente en tres partes. La primera de ellas ofrece una descripción general de los beneficios del uso de la fotónica en silicio para el desarrollo de enlaces inalámbricos a velocidades de Gbps, así como el estado del arte de los transceptores desarrollados por los grupos de investigación más activos y punteros para satisfacer las necesidades de mercado, cada vez más exigentes. La segunda parte se centra en el estudio y desarrollo del transmisor integrado de onda milimétrica. Primero realizamos una breve introducción teórica tanto del funcionamiento de los dispositivos que forman parte del transmisor, como a los formatos de modulación existentes, centrando la atención en la modulación por desplazamiento de fase (PSK) que es la que se va a utilizar en el desarrollo de los dispositivos implicados, y más concretamente en la modulación (diferencial) de fase en cuadratura ((D)QPSK). También se presentan los bloques básicos que integran nuestro transmisor y se fijan las especificaciones que deben cumplir dichos bloques para conseguir una transmisión libre de errores. El transmisor está compuesto por un filtro/demultiplexor encargado de separar dos portadoras ópticas separadas una frecuencia de 60 GHz. Una de estas portadoras es modulada al pasar por un modulador DQPSK basado en una estructura de dos MachZehnders (MZs) anidados, para ser nuevamente combinada con la otra portadora óptica que se ha mantenido intacta. Una vez combinadas, éstas son fotodetectadas para ser transmitidas inalámbricamente. En la tercera parte de esta tesis, se investiga el uso de un esquema de diversidad en polarización junto a un receptor DQPSK integrado para la demodulación de la señal recibida. El esquema de diversidad en polarización está formado básicamente por dos bloques: un separador de polarización con el objetivo de separar la luz a la entrada del chip en sus dos componentes ortogonales; y un rotador de polarización. En lo que se refiere al receptor DQPSK propiamente dicho, se ha investigado y optimizado cada uno de los bloques funcionales que lo componen. Éstos son básicamente un divisor de potencia termo-ópticamente sintonizable basado en un interferómetro MZ, en serie con un interferómetro MZ que introduce un retardo de duración de un bit en uno de sus brazos, para obtener una correcta demodulación diferencial. El siguiente bloque que forma parte de nuestro receptor DQPSK es un 2x4 acoplador de interferencia multimodal actuando como un híbrido de 90 grados, cuyas salidas van a parar a dos fotodetectores balanceados de germanio. Las contribuciones principales de esta tesis han sido: ¿ Demostración de un filtro/demultiplexor con tres grados de sintonización con una relación de extinción superior a 25dB. ¿ Demostración de un rotador con una longitud de tan sólo 25µm y CMOS compatible. ¿ Demostración de un modulador DPSK a una velocidad máxima de 20 Gbit/s. ¿ Demostración de un demodulador DQPSK a una velocidad máxima de 20 Gbit/s.Due to the relentless emergence of multifunction mobile devices with applications that require increasingly greater bandwidth at anytime and anywhere, future access networks must be capable of providing both wireless and wired services. The use of optical communications systems as transport medium of wireless signals over fiber radio links is a steady solution to be taken into account. This will make possible a convergence to an optical domain reducing and alleviating the bottleneck between wireless access standards and current wired access. In this thesis, as part of the objectives of the European project HELIOS in which it is framed, we have investigated and developed the basic functional blocks needed to achieve an integrated photonic transceiver working in the range of millimetre wavelengths, and using robust modulation formats that best fit the scope considered. The work presented in this thesis can be basically divided into three parts. The first one provides an overview of the benefits of using silicon photonics for the development of wireless links at rates of Gbps, and the state of the art of the transceivers reported by the most important research groups in order to meet the increasingly demanding needs¿ market. The second part focuses on the study and development of millimetre-wave integrated transmitter. First we provide a brief theoretical introduction of the operation principles of the devices involved in the transmitter such as a modulation formats, focusing on the phase shift keying (PSK) which is the one that will be used, particularly the (differential) quadrature phase shift keying ((D) QPSK). We also present the building blocks involved in our transmitter and we set the specifications that must be met by these devices in order to achieve an error-free transmission. The transmitter includes a filter/demultiplexer which must separate two optical carriers 60 GHz separated. One of these optical carriers is modulated by passing through a DQPSK Mach-Zehnder-based modulator (MZM) by arranging two MZMs in a nested configuration. Using a combiner, the modulated optical signal and the un-modulated carrier are combined and photodetected to be transmitted wirelessly. In the third part of this thesis, we investigate the use of a polarization diversity scheme with an integrated DQPSK receiver for demodulating of the wireless signal. The polarization diversity scheme basically consists of two blocks: a polarization splitter in order to separate the random polarization state of the incoming light into its two orthogonal components, and a polarization rotator. Regarding the DQPSK receiver itself, all the functional blocks that comprise it have been investigated and optimized. It basically includes a thermo-optically tunable MZ interferometer power splitter, in series with a MZ interferometer that introduces, in one of its arms, a delay of one bit length in order to obtain a correct differential demodulation. The next building block of our DQPSK receiver is a 2x4 multimode interference coupler acting as a 90 degree hybrid, whose outputs are connected to two balanced germanium photodetectors. The main contributions of this thesis are: ¿ Demonstration of a filter/demultiplexer with three degrees of tuning and an extinction ratio greater than 25dB. ¿ Demonstration of a polarization rotator with a length of only 25¿m and CMOS compatible. ¿ Demonstration of a DPSK modulator at a maximum rate of 20 Gbit/s. ¿ Demonstration of a DQPSK demodulator to a maximum rate of 20 Gbit/s.Aamer, M. (2013). Development of an integrated silicon photonic transceiver for access networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31649TESI

NASA Tech Briefs, August 1992

Topics include: Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Isolating Power Amplifiers for Parallel Transmit MRI

A radio frequency parallel transmitter was developed for magnetic resonance imaging. Eight channels of vector modulation and isolating power amplifiers were constructed so that the performance of different amplifier architectures could be investigated. An eight channel system was implemented and tested using both quantitative bench measurements and imaging experiments. The imaging experiments were performed on three separate MR systems at 3T, 4.7T, and 7T at different sites using both B1 shimming and fast modulation techniques. The modulation system implemented is based on vector modulators in order to simplify integration with existing MRI systems. Current Source and Low Output Impedance amplifiers were built and compared in terms of theory of operation, their ability to isolate array coils, and the amount of power they can deliver to a coil. The current source amplifiers function by introducing a high impedance in series with the coil which is series resonant. In contrast, the low output impedance amplifiers present a low impedance to the coil which has a matching network that forms a parallel resonant tank. Both are able to provide isolation, with the current source amplifiers producing in excess of 30dB of isolation and low output impedance amplifiers providing approximately 12.5dB in practical situations. The current source amplifiers can only produce approximately 10A (or between 150W and 300W) of output power because they are not power matched. In contrast, the low output impedance amplifiers can produce roughly 1kW (the device rating) because they are power matched. Ultimately, there is no single best architecture of power amplifiers at this time. Standard amplifiers are useful when only one or two transmit channels are needed and broad-bandedness is valuable. Current source amplifiers are best suited to situations where very high channel counts are needed because of their high isolation. Low output impedance amplifiers are most useful with moderate channel counts because they provide some isolation at moderately high powers

WDM/TDM PON bidirectional networks single-fiber/wavelength RSOA-based ONUs layer 1/2 optimization

This Thesis proposes the design and the optimization of a hybrid WDM/TDM PON at the L1 (PHY) and L2 (MAC) layers, in terms of minimum deployment cost and enhanced performance for Greenfield NGPON. The particular case of RSOA-based ONUs and ODN using a single-fibre/single-wavelength is deeply analysed. In this WDM/TDM PON relevant parameters are optimized. Special attention has been given at the main noise impairment in this type of networks: the Rayleigh Backscattering effect, which cannot be prevented. To understand its behaviour and mitigate its effects, a novel mathematical model for the Rayleigh Backscattering in burst mode transmission is presented for the first time, and it has been used to optimize the WDM/TDM RSOA based PON. Also, a cost-effective, simple design SCM WDM/TDM PON with rSOA-based ONU, was optimized and implemented. This prototype was successfully tested showing high performance, robustness, versatility and reliability. So, the system is able to give coverage up to 1280 users at 2.5 Gb/s / 1.25 Gb/s downstream/upstream, over 20 Km, and being compatible with the GPON ITU-T recommendation. This precedent has enabled the SARDANA network to extend the design, architecture and capabilities of a WDM/TDM PON for a long reach metro-access network (100 km). A proposal for an agile Transmission Convergence sub-layer is presented as another relevant contribution of this work. It is based on the optimization of the standards GPON and XG-PON (for compatibility), but applied to a long reach metro-access TDM/WDM PON rSOA-based network with higher client count. Finally, a proposal of physical implementation for the SARDANA layer 2 and possible configurations for SARDANA internetworking, with the metro network and core transport network, are presented

Telecommunications system of a CubeSat satellite

This Final degree's thesis is done under the UPC-Canadà program in which the author realizes his last degree year in Montréal, Canada, to the Polytechnique de Montréal university under the supervision of Dr. Giovanni Beltrame being part of his laboratory Mistlab and also on the Polyorbite group of students. Polyorbite is an organization that participates in the biannual contest CSDC (Canadian Satellite Design Challenge) that consists on the realization from 0 of a 3U CubeSat by undergraduate and master students. By the start of this thesis on September 2016, the contest was in the middle of the 2014-2016 iteration without having almost nothing on the telecommunication part, having just 2 semesters for design, build and test an entirely telecommunications system, suitable for the satellite purpose, until June 2016 in which the final presentations of the contest took place on Ottawa. The purpose of this thesis is then an early design of a telecommunications system for a CubeSat satellite

VLSI Design

This book provides some recent advances in design nanometer VLSI chips. The selected topics try to present some open problems and challenges with important topics ranging from design tools, new post-silicon devices, GPU-based parallel computing, emerging 3D integration, and antenna design. The book consists of two parts, with chapters such as: VLSI design for multi-sensor smart systems on a chip, Three-dimensional integrated circuits design for thousand-core processors, Parallel symbolic analysis of large analog circuits on GPU platforms, Algorithms for CAD tools VLSI design, A multilevel memetic algorithm for large SAT-encoded problems, etc

The Microstrip SQUID Amplier in the Axion Dark Matter eXperiment (ADMX)

We present the development and performance of low noise tunable Microstrip SQUID Amplifiers (MSAs) operating at frequencies near 1 GHz for use in ADMX. The MSA has been used in ADMX to produce published exclusions to the axion mass and density in our galactic dark matter halo.The exclusions published by ADMX and achieved with an MSA are the most stringent exclusions to date.Hypotheses on the nature of dark matter vary, so that the designs and operating principles of experimental dark matter searches vary as well. Every search is similar in that it is an endeavor to discover some very small signal--if the signal were not currently beyond perception we would not call our quarry ``dark matter". In ADMX the principle of operation is to convert axions into photons in a strong magnetic field, enhance that conversion rate with a resonant cavity tuned to the photon frequency, and record the presence of those converted photons. The trick in any direct detection experiment is to increase signal and decrease noise. In ADMX, the signal is increased by using a strong magnetic field, a high-Q cavity, and as large a volume as possible. The noise is reduced by operating at a low physical temperature and using a low-noise amplifier. That amplifier is the titular MSA. The MSA operates as a DC-Superconducting QUantum Interference Device (DC-SQUID) coupled to a RF microstrip resonator such that the magnetic field component of a standing wave on the microstrip couples to the SQUID, generating an amplified voltage signal across the SQUID terminals, which is transmitted to the rest of the detection chain. The MSA has a noise temperature of 50 to 200 mK, enabling a search rate about 56 times faster than would be possible using the best available commercial microwave amplifiers.We present background motivations and theoretical underpinnings to the axion dark matter search at a level appropriate for the graduate student first entering the field. We also include a substantial discussion of practical considerations and methods intended as a ``quick-start" guide for experimentalists. Our guiding principle is to provide the handbook we wish we had owned as a graduate student in physics first approaching the dark matter search, axion physics, and MSA design.We demonstrate MSAs operating at frequencies as low as 350 MHz and as high as 1,160 MHz with a typical Q of 60, typical gain of 20 dB, and typical tunability range of about about 20% of the center frequency. We use GaAs varactor diodes to tune the MSAs, and demonstrate a surprising transition in varactor capacitance between about 2 K and 200 mK, which we believe has not been reported to date and may shed light on the theory of shallow negative U centers in semiconductors

NASA Tech Briefs, April 1992

Topics covered include: New Product Ideas; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences

COBE's search for structure in the Big Bang

The launch of Cosmic Background Explorer (COBE) and the definition of Earth Observing System (EOS) are two of the major events at NASA-Goddard. The three experiments contained in COBE (Differential Microwave Radiometer (DMR), Far Infrared Absolute Spectrophotometer (FIRAS), and Diffuse Infrared Background Experiment (DIRBE)) are very important in measuring the big bang. DMR measures the isotropy of the cosmic background (direction of the radiation). FIRAS looks at the spectrum over the whole sky, searching for deviations, and DIRBE operates in the infrared part of the spectrum gathering evidence of the earliest galaxy formation. By special techniques, the radiation coming from the solar system will be distinguished from that of extragalactic origin. Unique graphics will be used to represent the temperature of the emitting material. A cosmic event will be modeled of such importance that it will affect cosmological theory for generations to come. EOS will monitor changes in the Earth's geophysics during a whole solar color cycle