Towards Radio Analog Signal Processing

RÉSUMÉ La demande insatiable pour les services de radio et communication à large bande, stimule les fabricants à chercher des nouvelles façons d’augmenter la largeur de bande spectrale des systèmes. Traitement numérique du signal (DSP) comme la technologie la plus commune des radios d’aujourd’hui est souple, reproductible, compact, et fiable en basse fréquence. Cependant,le système digital est plage dynamique limitée, le largeur de bande du système DSP est limité par la fréquence d’échantillonnage. A haute fréquence, telles que la fréquence d’onde millimétrique, le système DSP a un manque de performance et une consommation de puissance excessive. En outre, la complexité et le coût de système augmente aux fréquences plus élevées. Contrairement à DSP, les systèmes traitement radio-analogique du signal (R-ASP) sont bonnes performances à haute fréquence. Les systèmes R-ASP manipulent des signaux à large bande, temporellement sous leur forme analogique d’origine. Donc, ils n’ont pas besoin des convertisseurs A/D et D/A, et des convertisseurs haut/bas, résultant complexité inférieure à vitesse plus élevée, ce qui peut offrir des solutions sans précédent dans le domaine de l’ingénierie de radio. Phaser comme une structure de délai dispersive (DDS) contrôlable est le noyau d’un système R-ASP. Les composantes des fréquences du signal dans le temps se différencient après avoir traversé un phaser. Cette caractéristique du phaser le rend pratique pour l’application radio analogique haute vitesse, comme renifleur de spectre, multiplexage par division de fréquence (FDM), et impulsion radio. Cette thèse par articles présente les concepts et les améliorations R-ASP, sur la base du phaser, comme une alternative potentielle au traitement basé sur DSP, pour l’application de radio haute fréquence et haute vitesse. Le premier Chapitre traite de la motivation R-ASP, contributions de la thèse et de l’organisation. Les concepts et les caractéristiques du phaser,les nouvelles techniques pour améliorer la dispersion des phasers ainsi que la performance du système R-ASP, en fonction des applications sont proposées dans le Chapitre 2. Les Chapitres 3 à 6 sont les articles qui introduisent des nouvelles applications du R-ASP. Dans le Chapitre 3, une nouvelle technique de loop afin d’améliorer la résolution du phaser est proposé. En plus des fréquence mètres et les discriminateurs de fréquence, cette technique peut facilement appliquer à divers autres systèmes en temps réel, tels que les transformateurs de Fourier en temps réel, convolveurs, corrélateurs, et les radars compressifs.----------ABSTRACT Insatiable demand for broadband radio and communication services spurs the manufacturers to seek new ways to increase the spectral bandwidth of the systems. Digital Signal Processing (DSP) as the most common technology of Today’s radios is flexible, reproducible, compact, and reliable at low spectral bandwidth. However, digital system is limited precision and dynamic range, the bandwidth of the DSP system is limited by sampling rate. At high frequency, such as millimeter-wave frequency, the DSP system is poor performance and power hungry. Moreover, the complexity and cost of the system increase at higher frequency. In contrast of DSP, Radio-Analog Signal Processing (R-ASP) systems have a good performance at high frequency. R-ASP systems manipulate broadband signals, temporally in their original analog form. So, They don’t need A/D and D/A, and up/down converters, resulting lower complexity at higher speed, which may offer unprecedented solutions in the major areas of radio engineering. Phaser as an engineerable dispersive delay structure (DDS) is the core of an R-ASP system. The component frequencies of the signal differentiate in time after passing through a phaser. This characteristic of the phaser makes it convenient for high speed analog radio application, such as frequency sniffer, frequency division multiplexing (FDM), and impulse radio. This paper based dissertation introduces R-ASP concepts and enhancements, based on the phaser, as a potential alternative to DSP-based processing, for high speed and high frequency radio applications. The first Chapter discusses R-ASP motivation, thesis contributions and organization. The concepts of the phaser and phaser characteristics, new techniques to enhance the dispersion of the phasers as well as performance of the R-ASP system, depending on the applications are proposed in Chapter 2. Chapters 3 to 6 are the articles that introduce new applications of ASP. In Chapter 3, a novel loop technique to enhance the resolution of the phaser is proposed. In addition to frequency meters and frequency discriminators, this technique may readily by applied to various other real-time systems, such as real-time Fourier transformers, convolvers, correlators, and compressive radars. The radio-analog signal processing system has a lot of applications in the impulse regime. However, UWB pulse generation is complex and high cost. This issue is addressed in Chapter 4, proposing a low-cost analog pulse compression technique for UWB pulse generation. In Chapter 5, a stepped group delay phaser is introduced for real-time spectrum sniffing application. The system listens to its radio environment through an antenna, and determines, in real time, the presence or absence of active channels in this environment

Advanced Techniques for the Characterization and Experimental Validation of Passive Inter-Modulation Effect (PIM) in Space Communications Systems

[ES] Los satélites de telecomunicación operan en entornos multiportadora, bajo una demanda continua de mayores capacidades de transmisión. Esto ha originado un aumento en los niveles de potencia de RF, frecuencias de trabajo, y número de canales transmitidos, estimulando la aparición de efectos no lineales de alta potencia, como Multipactor, Corona, y la Intermodulación Pasiva (PIM). Entre los efectos anteriores, el PIM es el menos comprendido, debido a su carácter no lineal y su estrecha relación con la fabricación, lo que dificulta el desarrollo de modelos fiables. Los términos de PIM generados en el enlace descendente pueden interferir a la débil señal en el canal de recepción, amenazando la capacidad de recepción del enlace ascendente. Los modelos tradicionales de PIM suelen basarse en una excitación formada por dos portadoras. Aunque se trata de un caso simple y bastante representativo, presenta diferencias importantes con el escenario real multiportadora. El trabajo de este Ph.D. intenta reducir estas diferencias. Para lograrlo, se realizan dos nuevas contribuciones de relevancia para las condiciones reales de operación de los satélites. En concreto, se ha investigado de forma teórica el rol de las fases de las portadoras en el PIM, y se ha propuesto un nuevo modelo que tiene en cuenta el efecto de las portadoras no contribuyentes en un cierto término de PIM, aplicando un nuevo principio de conservación de energía. Los resultados obtenidos con ambos modelos teóricos se ajustan a los datos experimentales. Debido a la compleja naturaleza del PIM, la validación de los componentes de RF de satélites se realiza mediante tests. Por lo tanto, la disponibilidad de bancos de medida de PIM es un tema de interés para la industria espacial. Sin embargo, el diseño de bancos de altas prestaciones es un desafío, ya que su nivel de PIM debe ser inferior al requerido para validar los dispositivos. Para hardware de satélites, la diferencia entre el nivel de las portadoras a transmitir y la señal de RF a detectar es como 185 dBc. En este Ph.D. se proponen unas nuevas arquitecturas integradas de bancos de PIM en guía de ondas, que cubren tanto el PIM conducido como el radiado. Dichas arquitecturas permiten una reducción importante del nivel de PIM residual del sistema de medida, siendo flexibles, capaces de manejar elevados niveles de potencia, y libres de resonancias e interacciones indeseadas. Los elementos claves de estos bancos son unos multiplexores de bajo PIM, que pueden incorporar dos familias de filtros que admiten un elevado número de ceros de transmisión, y por tanto, son capaces de proporcionar un elevado rechazo en la banda de recepción del PIM. Los bancos de medida de PIM conducido por onda reflejada, sin embargo, están expuestos al PIM generado por la carga empleada para absorber las portadoras de alta potencia. Para resolver esta situación, se han propuesto unas nuevas cargas de bajo PIM, que reducen el PIM residual de estos sistemas de medida. Así mismo, se ha elaborado un nuevo tipo de transición para mitigar el PIM respecto a flanges estándar. Para escenarios radiados se ha desarrollado una formulación capaz de relacionar densidades de potencia en el dispositivo bajo test con los niveles detectados en el banco de medida, y que por tanto permiten trasladar especificaciones de PIM del satélite al sistema de medida. Por último, se han mostrado varias campañas de medida de PIM realizadas con bancos implementados acorde a las nuevas arquitecturas propuestas. Las medidas cubren varias bandas de frecuencia y diferentes escenarios (tanto PIM conducido como radiado). Se ha determinado el excepcional nivel de fondo de ruido de PIM logrado en cada banco. Además, se han mostrado resultados obtenidos para medidas de PIM radiado en capas aislantes multicapa y mallas reflectoras, obteniendo interesantes conclusiones en cuanto a geometrías y impacto que tienen en el PIM elementos como los bordes serrados y los remaches.[CA] Els satèl·lits de telecomunicació operen en entorns multiportadora, sota una demanda contínua de majors capacitats de transmissió. Això ha originat un augment en els nivells de potència de *RF, freqüències de treball, i nombre de canals transmesos, estimulant l'aparició d'efectes no lineals d'alta potència, com *Multipactor, Corona, i la Intermodulació Passiva (*PIM). Entre els efectes anteriors, el *PIM és el menys comprés, a causa del seu caràcter no lineal i la seua estreta relació amb la fabricació, la qual cosa dificulta el desenvolupament de models fiables. Els termes de *PIM generats en l'enllaç descendent poden interferir al feble senyal en el canal de recepció, amenaçant la capacitat de recepció de l'enllaç ascendent. Els models tradicionals de *PIM solen basar-se en una excitació formada per dues portadores. Encara que es tracta d'un cas simple i bastant representatiu, presenta diferències importants amb l'escenari real multiportadora. El treball d'aquest *Ph.D. intenta reduir aquestes diferències. Per a aconseguir-ho, es realitzen dues noves contribucions de rellevància per a les condicions reals d'operació dels satèl·lits . En concret, s'ha investigat de manera teòrica el rol de les fases de les portadores en el *PIM, i s'ha proposat un nou model que té en compte l'efecte de les portadores no contribuents en un cert terme de *PIM, aplicant un nou principi de conservació d'energia. Els resultats obtinguts amb tots dos models teòrics s'ajusten a les dades experimentals. A causa de la complexa naturalesa del *PIM, la validació dels components de *RF de satèl·lits es realitza mitjançant tests. Per tant, la disponibilitat de bancs de mesura de *PIM és un tema d'interés per a la indústria espacial. No obstant això, el disseny de bancs d'altes prestacions és un desafiament, ja que el seu nivell de *PIM ha de ser inferior al requerit per a validar els dispositius. Per a maquinari de satèl·lits , la diferència entre el nivell de les portadores a transmetre i el senyal de *RF a detectar és com 185 *dBc. En aquest *Ph.D. es proposen unes noves arquitectures integrades de bancs de *PIM en guia d'ones, que cobreixen tant el *PIM conduït com el radiat. Aquestes arquitectures permeten una reducció important del nivell de *PIM residual del sistema de mesura, sent flexibles, capaces de manejar elevats nivells de potència, i lliures de ressonàncies i interaccions indesitjades. Els elements claus d'aquests bancs són uns multiplexors de baix *PIM, que poden incorporar dues famílies de filtres que admeten un elevat nombre de zeros de transmissió, i per tant, són capaces de proporcionar un elevat rebuig en la banda de recepció del *PIM. Els bancs de mesura de *PIM conduït per ona reflectida, no obstant això, estan exposats al *PIM generat per la càrrega emprada per a absorbir les portadores d'alta potència. Per a resoldre aquesta situació, s'han proposat unes noves càrregues de baix *PIM, que redueixen el *PIM residual d'aquests sistemes de mesura. Així mateix, s'ha elaborat un nou tipus de transició per a mitigar el *PIM respecte a *flanges estàndard. Per a escenaris radiats s'ha desenvolupat una formulació capaç de relacionar densitats de potència en el dispositiu sota test amb els nivells detectats en el banc de mesura, i que per tant permeten traslladar especificacions de *PIM del satèl·lit al sistema de mesura. Finalment, s'han mostrat diverses campanyes de mesura de *PIM realitzades amb bancs implementats concorde a les noves arquitectures proposades. Les mesures cobreixen diverses bandes de freqüència i diferents escenaris (tant *PIM conduït com radiat). S'ha determinat l'excepcional nivell de fons de soroll de *PIM reeixit en cada banc. A més, s'han mostrat resultats obtinguts per a mesures de *PIM radiat en capes aïllants multicapa i malles reflectores, obtenint interessants conclusions quant a geometries i impacte que tenen en el *PIM elements com les vores serrades i els reblons.[EN] Modern satellite payloads operate in multicarrier scenarios, under a continuous demand for higher capacity links. This leads to an increase in the RF power levels, frequency of operation, and the number of transmitted channels, thus stimulating non-linear high-power effects, such as Multipactor, Corona, thermal issues and Passive Inter-Modulation (PIM). Among the above-mentioned phenomena, PIM is the less studied, or, at least, understood. This is due to its extreme non-linear nature and its close relation to workmanship, which make very difficult the development of models able to faithfully predict and explain PIM degradation. PIM terms, once ignited in the downlink, may interfere the weak signal to be detected in the uplink channel, thus threatening the payload throughput. Traditional PIM models are based on a two-carriers excitation. This is a simple and quite representative case, but has significant differences with the real multi- carrier scenario. This Ph.D. thesis work tries to diminish this gap by two novel contributions of relevance for real operation conditions. Firstly, the role of the carrier phases (neglected for two-carriers excitation) has been theoretically investigated. Secondly, a new model to account for the effect of non-contributing carriers for a given PIM term has been developed, which is based on a novel energy conservation assumption. The resulting models fit to experimental data. Due to the complexity of PIM modeling, PIM validation of RF components is conducted only by testing. The availability of low PIM test set-ups is therefore of great interest for the space industry. However, the design of low PIM test benches is challenging, as their intrinsic residual PIM has to be below the one requested to validate the test devices. For satellite hardware, the dynamic range between the RF power levels of the transmission carriers and the signal to be detected may be 185 dBc. During this Ph.D. thesis work, novel integrated test bed architectures in waveguide technology, both for conducted and radiated PIM scenarios, have been developed. These architectures consent a mitigation of the residual PIM of the test facility, being at the same time flexible, free from unwanted interactions and spurious resonances, and able to withstand considerable RF power levels for the transmission carriers. The key elements of these set-ups are the low PIM multiplexers, which may integrate two new families of waveguide filters able to provide a high number of transmission zeros, and therefore a high rejection, in the PIM reception channel. The test benches conceived for measuring conducted backward PIM, however, are normally unprotected from the PIM generated by the termination absorbing the high-power transmission carriers. To alleviate this situation, a new type of low PIM terminations in waveguide technology has been proposed and verified with PIM tests, showing a clear benefit in mitigating the residual PIM of the test facilities. Moreover, novel transitions able to improve the PIM performance of standard flanges have also been conceived. Finally, and with regard to radiated scenarios, a novel formulation able to convert payload PIM specifications to a practical PIM test is proposed. This formulation consents to link the power flux densities at the device under test (DUT) with the RF power levels measured by the test bench. Last, a large class of PIM measurements carried out with the novel test bed architectures have been reported. These measurements cover several frequency bands (C-, Ku-, K- and Ka) and different PIM scenarios, both conducted and radiated. The exceptional residual PIM noise floor of each test bed will be pointed out. In addition, PIM tests on an anechoic chamber facility, multi-layer insulation blankets (MLIs) and reflector mesh samples are presented, with interesting considerations about the geometry of the structure and the impact on the PIM performance of typical elements as sawing areas and rivets.Smacchia, D. (2022). Advanced Techniques for the Characterization and Experimental Validation of Passive Inter-Modulation Effect (PIM) in Space Communications Systems [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182402TESI

Photon signatures for standoff bomb detection

Master of ScienceDepartment of Mechanical and Nuclear EngineeringWilliam L. DunnThe purpose of this research was to develop a technology to quickly identify hidden explosive materials. The developed method needs to be performed at a standoff distance of approximately two meters or more, must have high sensitivity (low false-negative rate) and good specificity (low false-positive rate), and should be able to detect a minimum amount of approximately one gallon (15 lbs) of explosive material. In an effort to meet these goals, a template-matching procedure to aid in the rapid detection of hidden improvised explosive devices was investigated. Multiple photon-scattered responses are being used as a part of a multidimensional signature-based radiation scanning (SBRS) approach in an attempt to detect chemical explosives at safe, standoff distances. The SBRS approach utilizes both neutron and photon interrogation to determine if a target contains explosive material, but the focus of this thesis is on photon interrogation. Beams of photons are used to create back-streamed responses called signatures, which are dependent on the density and the composition of the target. These signatures are compared to templates, which are collections of the same signatures if the interrogated volume contained a significant amount of explosives. The signature analysis produces a single figure-of-merit. A low figure-of-merit indicates an explosive might be present in the target. Experiments have been conducted that show an explosive surrogate (fertilizer) can be distinguished from several inert materials using these photon signatures, proving these signatures to be very useful in this particular method of chemical explosive detection

Large-Scale Photonics Integration: Data Communications to Optical Beamforming

Integrated photonics is an emerging technology that has begun to transform our way of life with the same amount of impact that integrated CMOS electronics has. Currently, photonics integration is orders of magnitude less complicated than its electronics counterparts. Nonetheless, it serves as one of the main driving forces to meet the exponentially increasing demand for high-speed and low-cost data transfer in the Information Age. It also promises to provide solutions for next-generation high-sensitivity image sensors and precision metrology and spectroscopy instruments. In this thesis, integrated photonics architectures for solid-state photonic beamforming and processing are investigated for high-resolution and high sensitivity lens-free transceiver applications. Furthermore, high-efficiency integrated electro-optical modulators aiming to meet the demand of high-density photonic integration with improved modulation efficiency, small footprint, and lower insertion loss are investigated. Two integrated photonic solid-state beamforming architectures incorporating two-dimensional apertures are explored. First, a novel transceiver architecture for remote sensing, coherent imaging, and ranging applications is demonstrated. It reduces system implementation complexity and offers a methodology for very-large-scale coherent transceiver beamforming applications. Next, a transmitter beamforming architecture inspired by the diffraction pattern of the slit annular ring is analyzed and demonstrated. This transceiver architecture can be used for coherent beamforming applications such as imaging and point-to-point optical communication. Finally, a coherent imager architecture for high-sensitivity three-dimensional imaging and remote-sensing applications is present. This novel architecture can suppress undesired phase fluctuations of the optical carrier signal in the illumination and reference paths, providing higher resolution and higher acquisition speed than previous implementations. Moreover, several compact, high-speed CMOS compatible modulators that enable high-density photonic integration are explored. Ultra-compact and low insertion loss silicon-organic-hybrid modulators are designed and implemented for high-speed beamforming and high-efficiency complex signal modulation applications. Finally, a novel integrated nested-ring assisted modulator topology is analyzed and implemented for high-density and high modulation efficiency applications.</p

Cumulative index to NASA Tech Briefs, 1963-1967

Cumulative index to NASA survey on technology utilization of aerospace research outpu

Research and Technology Objectives and Plans Summary (RTOPS)

A compilation of the summary portion of each of the Research and Technology Operating Plans (RTOP) used for management review and control of research currently in progress throughout NASA is presented along with citations and abstracts of the RTOPs. Four indexes are included: (1) subject; (2) technical monitor; (3) responsible NASA organization; and (4) RTOP number

Y-12 Plant decontamination and decommissioning technology logic diagram for Building 9201-4. Volume 3: Technology evaluation data sheets; Part A: Characterization, dismantlement

The Y-12 Plant Decontamination and Decommissioning Technology Logic Diagram for Building 9201-4 (TLD) was developed to provide a decision-support tool that relates decontamination and decommissioning (D and D) problems at Bldg. 9201-4 to potential technologies that can remediate these problems. The TLD uses information from the Strategic Roadmap for the Oak Ridge Reservation, the Oak Ridge K-25 Site Technology Logic Diagram, the Oak Ridge National Laboratory Technology Logic Diagram, and a previous Hanford logic diagram. This TLD identifies the research, development, demonstration, testing, and evaluation needed for sufficient development of these technologies to allow for technology transfer and application to D and D and waste management (WM) activities. It is essential that follow-on engineering studies be conducted to build on the output of this project. These studies will begin by selecting the most promising technologies identified in the TLD and by finding an optimum mix of technologies that will provide a socially acceptable balance between cost and risk. This report consists of the characterization and dismantlement data sheets

Langley Aerospace Research Summer Scholars

The Langley Aerospace Research Summer Scholars (LARSS) Program was established by Dr. Samuel E. Massenberg in 1986. The program has increased from 20 participants in 1986 to 114 participants in 1995. The program is LaRC-unique and is administered by Hampton University. The program was established for the benefit of undergraduate juniors and seniors and first-year graduate students who are pursuing degrees in aeronautical engineering, mechanical engineering, electrical engineering, material science, computer science, atmospheric science, astrophysics, physics, and chemistry. Two primary elements of the LARSS Program are: (1) a research project to be completed by each participant under the supervision of a researcher who will assume the role of a mentor for the summer, and (2) technical lectures by prominent engineers and scientists. Additional elements of this program include tours of LARC wind tunnels, computational facilities, and laboratories. Library and computer facilities will be available for use by the participants

NASA Tech Briefs, Winter 1977

Topics include: NASA TU Services: Technology Utilization services that can assist you in learning about and applying NASA technology; New Product Ideas: A summary of selected innovations of value to manufacturers for the development of new products; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Life Sciences; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences