Engineering evaluations and studies. Volume 3: Exhibit C

High rate multiplexes asymmetry and jitter, data-dependent amplitude variations, and transition density are discussed

The payload/shuttle-data-communication-link handbook

Communication links between the Orbiter, payloads, and ground are described: end-to-end, hardline, S-band, Ku-band, TDRSS relay, waveforms, premodulation, subcarrier modulation, carrier modulation, transmitter power, antennas, the RF channel, system noise, received signal-to-noise spectral density, carrier-tracking loop, carrier demodulation, subcarrier demodulation, digital data detection, digital data decoding, and tandem link considerations

Implementation of a X-mode multichannel edge density profile reflectometer for the new ICRH antenna on ASDEX Upgrade

Ion cyclotron resonance heating (ICRH) is one of the main heating mechanisms for nuclear fusion plas- mas. However, studying the effects of ICRH operation, such as power coupling efficiency and convective transport, requires the measurement of the local edge plasma density profiles. Two new three-strap an- tennas were designed to reduce tungsten impurity release during operation, and installed on ASDEX Upgrade. One of these ICRH antennas embedded ten pairs of small microwave pyramidal horn anten- nas. In this thesis, a new multichannel X-mode microwave reflectometry diagnostic was developed to use these embedded antennas to simultaneously measure the edge electron density profiles in front of the bottom, middle and top regions of the radiating surface of the ICRH antenna. Microwave reflectome- try is a radar technique that measures the round trip delay of probing waves that are reflected at specific cutoff layers, depending on the probing wave frequency, plasma density and local magnetic field. This diagnostic uses a coherent heterodyne quadrature detection architecture and probes the plasma in the range 40-68 GHz to measure plasma edge electron densities up to 2×1019 m-3, with magnetic fields between 1.85 T and 2.7 T, and a repetition interval as low as 25 μs. This work details the implementa- tion and commissioning of the diagnostic, including the calibration of the microwave hardware and the analysis of the raw reflectometry measurements. We study the automatic initialization of the X-mode upper cutoff measurement, which is the main source of error in X-mode density profile reconstruction. Two first fringe estimation algorithms were developed: one based on amplitude and spectral information and another using a neural network model to recognize the first fringe location from spectrogram data. Kalman filters are used to improve radial measurement uncertainty to less than 1 cm. To validate the diagnostic, we compared the density profile measurements with other electron density diagnostics on ASDEX Upgrade, and observed typical plasma phenomena like the L-H transition and ELM activity. The experimental density profile results were used to corroborate ICRH power coupling simulations under different gas puffing conditions and to observe poloidal convective transport during ICRH operation

On the capacity of relay networks with finite memory relays

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 125-132).(cont.) the length of relay memory and the number of relay stages.In this thesis, we examine the effect of relay memory on the capacity of two types of relay channels. In the first part of the thesis, we present a parallel relay channel model. Under this particular model, intermediate processing at the relays is distributed and cooperative. We derive the capacity by making use of the direct relation between capacity and estimation theory. We show that the capacity of the channel under distributed relay processing by a Kalman filter and that of the channel under optimal relay processing are equal. Using a one dimensional (1D) Kalman filter, processing at individual relays requires infinite memory, assuming that the channel is subject to inter-symbol interference (ISI). For a channel with ISI, we show that a two dimensional (2D) Kalman filter allows the memory for processing at individual relays to be finite. In the second part of the thesis, we present a serial relay channel model. Under this particular model, one section of the channel is coupled with the next by a memoryless relay. Assuming the channel is subject to energy constraints and finite end-to-end noise power, we show that the capacity tends to infinity asymptotically in the number of relay stages. Given a finite number of relay stages, finding maximum mutual information subject to energy constraints alone is difficult. Thus, in addition to energy constraints, we propose entropy constraints. We give an explicit upper bound to capacity, assuming the channel is subject to the proposed set of constraints on the channel input as well as the relay outputs. We illustrate the use of our upper bound numerically and contrast it versus several lower bounds. Next, we relax the memoryless restriction, thus allow coding and decoding at the relays. We show two trade-offs concerningby Nathanael Peranginangin.Sc.D

Publications of the Jet Propulsion Laboratory, January through December 1974

Formalized technical reporting is described and indexed, which resulted from scientific and engineering work performed, or managed, by the Jet Propulsion Laboratory. The five classes of publications included are technical reports, technical memorandums, articles from the bimonthly Deep Space Network Progress Report, special publications, and articles published in the open literature. The publications are indexed by author, subject, and publication type and number

Theory, design and application of gradient adaptive lattice filters

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