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Millimeter wave amplification using an electron beam-plasmaNiemann, Ronald Gerald. January 1981 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 109-110).
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Phase noise reduction of high speed frequency dividers in deep sub micron CMOS /Prakash, Rahul, January 2006 (has links)
Thesis (M.S.)--University of Texas at Dallas, 2006 / Includes vita. Includes bibliographical references (leaves 97-98)
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Design and implementation of a novel low noise low distortion frequency modulation radio receiver front-endHu, Jingyu, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
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The experimental design and characterisation of Doherty power amplifiers /Brand, Konrad Frederik. January 2006 (has links)
Thesis (MScIng)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.
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Design considerations for a computationally-lightweight authentication mechanism for passive RFID tagsFrushour, John H. January 2009 (has links) (PDF)
Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2009. / Thesis Advisor(s): Fulp, J.D. ; Huffmire, Ted. "September 2009." Description based on title screen as viewed on November 6, 2009. Author(s) subject terms: Passive RFID Systems, Tags, Clock, Electro-magnetic induction, authentication, hash, SHA--1. Includes bibliographical references (p. 59-60). Also available in print.
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Benefits to processor load for quadrature baseband versus radio frequency demodulation algorithms /Ndovi, Lusungu. January 2008 (has links)
Thesis (MScIng)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.
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Performance analysis of diversity combining for frequency-hop communications under partial-band and multitone interferenceLi, Gang 04 July 2018 (has links)
This dissertation is concerned with performance analysis of diversity combining
schemes in frequency-hop spread spectrum communications under the worst case partial-band noise and multitone jamming.
Performance of a ratio-threshold diversity combining scheme in fast frequency
hop spread spectrum systems with M-ary frequency shift keying modulation
(FFH/MFSK ) under partial-band noise (PBN) and band multitone jamming without
and with the additive white Gaussian noise (AWGN) is analyzed. The analysis
is based on exact bit error probabilities, instead of bounds on the bit error probabilities.
A method to compute the bit error probability for ratio-threshold combining
on jamming channel is developed. Relationship between the system performance
and the system parameters, such as ratio-threshold, diversity order, and thermal
noise level, is illustrated. The performances under band multitone jamming and
under partial-band noise jamming are compared. For binary FSK modulation, the
performance under the two types of jamming is almost the same, but for 8-ary
FSK modulation, tone jamming is more effective against communications. The
structure of the combiner is very simple and easy to implement. Another merit of
this combiner is that its output can be directly fed to a soft-decision FEC decoder.
Maximum-likelihood diversity combining for an FFH/MFSK spread spectrum
system on a PBN interference channel is investigated. The structure of maximum
likelihood diversity reception on a PBN channel with AWGN is derived. It is
shown that signal-to-noise ratio and the noise variance at each hop have to be
known to implement this optimum diversity combining. Several sub-optimum diversity
combining schemes, which require the information on noise variance of each
hop to operate, are also considered. The performance of the maximum-likelihood
combining can be used as a standard in judging the performance of other suboptimum, but more practical diversity combining schemes. The performance of
the optimum combining scheme is evaluated by simulations. It is shown that the
Adaptive Gain Control (AGC) diversity combining actually achieves the optimum
performance when interference is not very weak. But the performance difference
between some of the known diversity combining schemes, which do not require
channel information to operate, and the optimum scheme is not small when the
diversity order is low.
An error-correction scheme is proposed for an M-ary symmetric channel characterized
by a large error probability Pe. Performance of the scheme is analyzed.
The value of Pe can be close to, but smaller than, 1 – 1/M for which the channel
capacity is zero. Such a large Pe may occur, for example, in a jamming environment. The coding scheme considered consists of an outer convolutional code
and an inner repetition code of length m which is used for each convolutional
code symbol. At the receiving end, the m inner code symbols are used to form
a soft-decision metric, which is subsequently passed to a soft-decision decoder for
the convolutional code. Emphasis is placed on using a binary convolutional code
due to the consideration that there exist commercial codecs for such a code. New
methods to generate binary metrics from M-ary (M > 2) inner code symbols
are developed. For the binary symmetric channel, it is shown that the overall
code rate is larger than O.6R0, where R0 is the cutoff rate of the channel. New
union bounds on the bit error probability for systems with a binary convolutional
code on 4-ary and 8-ary orthogonal channels are presented. Owing to the variable
m which has no effect on the decoding procedure, this scheme has a clear operational
advantage over some other schemes. For a BSC and a large m, a method
presented for BER approximation based on the central limit theorem. / Graduate
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Nonlinear optical spectroscopic studies of polymer surface properties and competition adsorption of toluene and heptane on silica surfacesHua, Rui 11 1900 (has links)
Surface properties of polymers and competition adsorption of toluene and heptane
on silica were studied using IR-visible sum frequency generation (SFG) vibrational
spectroscopy. SFG is intrinsically surface sensitive because the second-order optical
process is forbidden in media with inversion symmetry, such as bulk polymers and
liquids. This nonlinear optical technique provides surface vibrational spectra under
ambient conditions without the need of an ultra-high vacuum environment. Polymer
surface properties, including surface relaxation temperature of poly(methyl methacrylate)
(PMMA) and surface electronic states of poly[2-methoxy, 5-ethyl (2’-hexyloxy) para
phenylenevinylene] (MEH-PPV), were investigated. It was found that there are
significant differences between the surface and bulk properties for these polymers. For
PMMA, a new surface structure relaxation was identified at 67°C, which does not match
any known structure relaxation temperatures for bulk PMMA and is 40°C below the bulk
glass transition temperature. For MEH-PPV, SFG electronic spectra, which were
obtained by scanning the frequencies of incident visible and JR beams, indicated that the
electronic states at the polymer/solid and air/polymer interfaces are red-shifted with
respect to that of the bulk. Finally, SFG was employed to study the competition
adsorption of toluene and heptane on silica surfaces. Experimental data showed that
heptane adsorbed favorably compared to toluene. Using a Langmuir adsorption isotherm,
the changes of Gibbs free energy for the adsorption processes were calculated to be —12.1
± 1.8 (kJ/mol) for toluene and —16.5 ± 2.3 (kJ/mol) for heptane. / Science, Faculty of / Chemistry, Department of / Graduate
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Design of a metal detectorHaider, Ammar January 2018 (has links)
Electromagnetic wave propagation is a well-known phenomenon in the scientific world and when the first telescope was built method of sensing objects excelled afterwords. Research in optical system and infrared is growing day by day but radar system still dominates the world in object sensing. One of the benefits of using electromagnetic waves in a Radar system is that they can create images of areas which cannot be observed with optical light. Radars work on the basic phenomena of an extremely short burst of radio energy which transmit energy that reflects from the object as an echo. This principle is also known as ECHO Principal [13]. This thesis presents a Coffee Can radar system which gives detection of a stationary and moving object. Objects detection is performed on the oscilloscope using a triangular wave transmitted from an antenna, that gets reflected from an object and received on the second antenna. The prototype consists of two antennas one of which is used for transmitting signal and other is used for receiving signal. Voltage control oscillator is used to generate the RF frequency signal and power amplifiers are used before transmitting and receiving the RF signal. The signals are down-converted using a mixer the output of which is observed on an oscilloscope. Detection of the reflected signal can be performed using Doppler shift which can be determined from the velocity of electromagnetic radiation and angular displacement of the reflected waves. The wavelength of the Doppler shift is then used to indicate the detection and ranging of the object. Coffee Can radar operates at 2.4GHz with the output power of 10mW. Triangular wave signal is generated with the help of a wave generator. The radar prototype built in this thesis is used for detection and ranging of two different types of materials. First, is a metal sheet and secondly an aluminum foil. The detection process is completed by noting the Vpp values reflected from these sheets. Vpp values are measured on the oscilloscope when the signal reflected from aluminum sheet. With the help of a commercial software, aluminum foil presence is detected under the snow. For the future work if the video amplifier is built then the aluminum foil presence can be detected on MATLAB without the help of any commercial software. In future Coffee Can Radar can also be used for surveillance purposes like smart homes, autonomous vehicles and as a jammer. This Radar system can also be used as a data logging system.
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An exploration of the structural properties of L2 vocabulary networks : a graph theoretical approachSchur, Ellen January 2003 (has links)
No description available.
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