International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / In 1992, international space agencies became concerned that increasing frequency band congestion, together with attempts by the mobile telephone industry to obtain additional bandwidth, would result in substantially more interference incidents. The CCSDS undertook a technical study to identify and recommend more bandwidth efficient modulation schemes, which would permit more users to co-exist in a frequency band while reducing interference incidents. This paper describes the contribution of the Jet Propulsion Laboratory (JPL) to that effort.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Commercial FQPSK-B receivers traditionally use symbol-by-symbol detection and have a 2 dB Eb=No loss relative to ideal QPSK at a bit error rate (BER) of 10^(-5). An enhanced FQPSK-B receiver using a Viterbi algorithm (VA) to perform trellis decoding is simulated and shown to have a 1.2 dB Eb=No improvement over symbol-by-symbol detection for 10^(-5)5 BER at the cost of increased complexity. A simplified Viterbi receiver with a reduced trellis and significantly less complexity is introduced with only a slight BER degradation compared to the full Viterbi receiver. In addition, a theoretical bit error probability expression for the symbol-by-symbol FQPSK-B receiver is derived and compared with simulation results.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Instrumentation and Telemetry Departments at Sandia National Laboratories have been exploring the instrumentation of sealed canisters where the flight application will not tolerate either the presence of a chemical power source or penetration by power supply wires. This paper will describe the application of a low power micro-controller based instrumentation system that uses magnetic coupling for both power and data to support a flight application.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Because of the limits of feedback devices, high-speed pseudo-noise code generators cannot depend simply on the improvement of clock rate. Based on the characteristic equation of linear feedback registers and the m-sequence sampling theory as well, deduction is made to indicate a novel way to improve the speed of pseudo-noise code generators 2^l (2^l < n, n is the length of registers) times as fast as the conventional one. Also, we extend our applications to non-reducible and non-primitive polynomials. It could be a good way to generate these linear codes at higher rates.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The mathematics basis that can form a telemetry system is orthogonal functions. Three kinds of orthogonal functions are used up to now. First of them is sine and cosine function family. The second one is block pulse function family. The third one is Walsh function family. Their corresponding telemetry systems are FDM, TDM and SDM (CDM). Later we introduced an orthogonal function which is called Bridge function. The corresponding system is named telemetry system based on Bridge function. Now a new kind of orthogonal function, Generalized Bridge function, has been found. It can be applied to practical multiplex of information transmission. In this paper the author provides the design concept, block diagram, operational principle and technical realization of telemetry system based on Generalized Bridge function.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Dynamic hardware and software schemes for trajectory based simulation of LEO satellite channel are presented and evaluated. The simulation models are based on the practical LEO satellite channels and change dynamically with the trajectory using the latitude and longitude of the LEO satellite as input. The hardware simulator is consisted of a trajectory based selective fade generator, a trajectory based Doppler shifter, trajectory based time shadowing simulator and a standard channel for addition of noise, ACI and CCI. A FQPSK modulated signal is passed through a trajectory based dynamic fade generator and the spectrum is distorted. Then the resulting signal is exposed to a trajectory based dynamic Doppler Shifter, simulating the passage of the satellite overhead. Then the proper AWGN, ACI or CCI is added to the signal. At the final stage the signal is passed through a trajectory based time Shadowing simulator. The software simulator is a dynamic real time simulator written in MatLab and its structure is similar to the hardware simulator.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / This paper will discuss the use of a specialized telemetry signal simulator for pre-mission verification of a telemetry receiving system. This will include how to configure tests that will determine system performance under “real time” conditions such as multipath fading and Doppler shifting. The paper will analyze a telemetry receiving system and define tests for each part of the system. This will include tests for verification of the antenna system. Also included, will be tests for verification of the receiver/combiner system. The paper will further discuss how adding PCM simulation capabilities to the signal simulator will allow testing of frame synchronizers and decomutation equipment.

Field-effect transistors (FET) based on graphene as channel has extraordinaryproperties in terms of charge mobility, charge carrier density etc. However, there aremany challenges to graphene based FET due to the fact graphene is a monolayer ofatoms in 2-dimentional space that is strongly influenced by the operating conditions.One issue is that the Dirac point, or K-point, shifts to higher gate voltage whengraphene is exposed to atmosphere. In this study graphene field-effect transistors(GFET) based on commercially available CVD graphene are electrically characterizedthrough field effect gated measurements. The Dirac point is initially unobservable andlocated at higher gate voltages (&gt;+42 V), indicating high p-doping in graphene.Different treatments are tried to enhance the properties of GFET devices, such astransconductance, mobility and a decrease of the Dirac point to lower voltages, thatincludes current annealing, vacuum annealing, hot plate annealing, ionized water bathand UV-ozone cleaning. Vacuum annealing and annealing on a hot plate affect thegated response; they might have decreased the overall p-doping, but also introducedDirac points and non-linear features. These are thought to be explained by localp-doping of the graphene under the electrodes. Thus the Dirac point of CVDgraphene is still at higher gate voltages. Finally, the charge carrier mobility decreasedin all treatments except current – and hot plate annealing, and it is also observed that charge carrier mobilities after fabrication are lower than the manufacturer estimatesfor raw graphene on SiO2/Si substrate.

This ethnographic case study describes the patterns of language socialization and literacy/biliteracy practices and the patterns of language choice and language use of a Spanish heritage bilingual family of Mexican origin from the participant perspective, the emic view, and the research perspective, an etic view. This analysis attempts to broaden the knowledge of how Mexican origin families use language at home by demonstrating how literacy/biliteracy practices (i.e., reading, writing and talk/conversation), language choice (i.e., Spanish, English, code-switching (CS)) and language use (i.e., domains) contribute to reinforce, develop or hinder the use of Spanish as a heritage language. Using ethnographic methodology, this study analyzes the participants' naturally occurring language interactions. Socialization and language learning are seen as intricately interwoven processes in which language learners participate actively.The analysis and discussion is presented in two sections: 1) language socialization in conjunction with literacy practices, and 2) language socialization in conjunction with language choice and CS. Language choice and CS are analyzed by means of conversation analysis theory (CA): the analysis of language sequences of the participants' conversation. The description of the domains (i.e., what participants do with each language and the way they use language) constitutes the basis for the analysis.The findings of this study show that language shift to English is imminent in an environment of reduced contact with parents, siblings, and the community of the heritage language group. Understanding which literacy practices are part of the everyday life of Hispanic households is relevant to the implementation of classroom literacy practices.

Un automate cellulaire est un système dynamique discret qui modélise des objets ayant une évolution parallèle synchrone: l'espace est divisé en cellules ayant chacune un état et qui évoluent toutes selon une même règle locale, qui ne dépend que d'un nombre fini de cellules voisines. Malgré la simplicité de la formalisation de ce système, des comportements très complexes peuvent apparaître, qui en font notamment un modèle de calcul. Cette complexité a été rattachée à diverses théories: topologie, mesure, décidabilité, information...Nous adoptons ici une approche basée sur la dynamique symbolique, c'est à dire l'étude des mots infinis sur un alphabet donné auxquels on applique un décalage, suppression de la première lettre. À chaque automate cellulaire peut en effet être associé son tracé, l'ensemble des mots infinis représentant la séquence des états successifs pris par la cellule centrale de l'espace - ou un groupe de cellules centrales. On a alors une factorisation topologique: la lecture d'une lettre dans un de ces mots correspond exactement à une étape de l'évolution de l'automate. De nombreuses propriétés topologiques sont alors transmises par cette factorisation. Inversement, le fait que les cellules évoluent toutes de la même manière permet de déduire certaines propriétés de l'automate à partir de celles de son tracé. La première partie de la thèse est consacrée à ces nombreux liens. Une deuxième partie présente des conditions suffisantes pour qu'un ensemble de mots infinis soit le tracé d'un automate cellulaire. Enfin, une troisième partie donne un point de vue plus informatique, en récapitulant les principaux résultats d'indécidabilité sur le sujet et en prouvant que toutes les propriétés du tracé qui peuvent se voir infiniment tard sont indécidables