Spelling suggestions: "subject:"quadrature"" "subject:"guadrature""
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A Monolithic CMOS Realization of the Double-Quadrature Image-Reject Weaver ReceiverRussell, Mac 28 January 2020 (has links)
No description available.
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Lagrange-Chebyshev Based Single Step Methods for Solving Differential EquationsStoffel, Joshua David 07 May 2012 (has links)
No description available.
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Isogeometric Shell Analysis: Multi-patch Coupling and Overcoming LockingZou, Zhihui 08 April 2020 (has links)
The fundamental advantages of applying Isogeometric Analysis (IGA) to shell analysis have been extensively demonstrated across a wide range of problems and formulations. However, a phenomenon called numerical locking is still a major challenge in IGA shell analysis, which can lead to dramatically deteriorated analysis accuracy. Additionally, for complex thin-walled structures, a simple and robust coupling technique is desired to sew together models composed of multiple patches. This dissertation focuses on addressing these challenges of IGA shell analysis. First, an isogeometric dual mortar method is developed for multi-patch coupling. This method is based on Be ?zier extraction and projection and can be employed during the creation and editing of geometry through properly modified extraction operators. It is applicable to any spline space which has a representation in Be ?zier form. The error in the method can be adaptively controlled, in some cases recovering optimal higher-order rates of convergence, by leveraging the exact refineability of the proposed dual spline basis without introducing any additional degrees-of-freedom into the linear system. This method can be used not only for shell elements but also for heat transfer and solid elements, etc. Next, a mixed formulation for IGA shell analysis is proposed that addresses both shear and membrane locking and improves the quality of computed stresses. The starting point of the formulation is the modified Hellinger-Reissner variational principle with independent displacement, membrane, and shear strains as the unknown fields. To overcome locking, the strain variables are interpolated with lower-order spline bases while the variations of the strain variables are interpolated with the proposed dual spline bases. As a result, the strain variables can be condensed out of the system with only a slight increase in the bandwidth of the resulting linear system and the condensed approach preserves the accuracy of the non-condensed mixed approach but with fewer degrees-of-freedom. Finally, as an alternative, new quadrature rules are developed to release membrane and shear locking. These quadrature rules asymptotically only require one point for Reissner-Mindlin (RM) shell elements and two points for Kirchhoff-Love (KL) shell elements in B-spline and NURBS-based isogeometric shell analysis, independent of the polynomial order p of the elements. The quadrature points are Greville abscissae and the quadrature weights are calculated by solving a linear moment fitting problem in each parametric direction. These quadrature rules are free of spurious zero-energy modes and any spurious finite-energy modes in membrane stiffness can be easily stabilized by using a higher-order Greville rule.
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Quadrature Approximation of Matrix Functions, with ApplicationsMartin, David Royce 19 June 2012 (has links)
No description available.
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The Greek Method of Exhaustion: Leading the Way to Modern IntegrationDeSouza, Chelsea E. 27 June 2012 (has links)
No description available.
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Error estimates for Gauss-Jacobi quadrature formula and Padé approximants of Stieltjes series /Al-Jarrah, Radwan Abdul-Rahman January 1980 (has links)
No description available.
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Integrated Cmos Iq Upconverter/Downconverter for an X-Band Phased-Array Radar ApplicationJohnson, Ryan C 01 January 2011 (has links) (PDF)
This thesis describes the design and measurement of an X-band IQ up/down converter that has been fabricated on a 180nm RF CMOS process. This converter includes components for mixing, frequency doubling, quadrature generation, amplification, and limiting. The specific circuit topologies used include passive double-balanced mixers, RC polyphase filters, and injection locked LC oscillators.
The converter is part of a transceiver chain that will make up the dedicated circuitry for each active antenna element of a phased-array radar. An active antenna element combines a radiator with its own transceiver subsystem. A phased-array radar, NetRad, is under development at the University of Massachusetts Amherst and will require thousands of active antenna elements. This motivates the need for low-cost integrated solutions. A silicon-based RF CMOS process provides a low-cost candidate technology to fulfill this requirement.
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A Study of Sensitivity Mapping Techniques for Multi-Channel MR CoilsDalveren, Taylan 19 September 2013 (has links)
No description available.
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SPECTRAL EFFICIENCY OF COMMERCIAL WIRELESS AND TELEMETRY SYSTEMS IS DOUBLED WITH IRIG 106-00 STANDARDIZED FQPSK AND IS QUADRUPLED WITH FQAMFeher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Advances in spectrally efficient Feher’s Quadrature Phase Shift Keying (FQPSK) and Feher‘s
Quadrature Amplitude Modulation (FQAM) patented technologies, commercial and government
“dual-use” FQPSK products and Test & Evaluation (T&E) results are highlighted in this overview
paper. US and international customer requirements/systems, programs and recent deployments and
standardization programs are also described. FQPSK doubles the spectral efficiency of PCM/FM
Telemetry and of Feher patented Gaussian Minimum Shift Keying (GMSK or FGMSK) and of
alternatives, while FQAM quadruples the spectral efficiency of these systems. The predominant focus
of this presentation is on an overview and advances of IRIG 106-00 standardized FQPSK technologies.
FQAM systems will also be described. Use of FQPSK for applications such as telemetry, data links,
clear mode, TDMA ,CSMA and CDMA, OCDMA, WCDMA as well as OFDM – COFDM will be
included in the presentation.
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ADVANCED RANGE TELEMETRY (ARTM) TIER I COMPATIBLE DEMODULATOR TESTING AND RESULTSTemple, Kip 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / The Nova HYPERMOD demodulator operates in three modes, the classic pulse-code
modulation/frequency modulation (PCM/FM), sometimes known as continuous phase frequency shift
keying (CPFSK) mode, shaped offset quadrature phase shift keying (SOQPSK) mode, and continuous
phase modulation (CPM) mode. Of interest to this paper is SOQPSK mode which is a waveform similar
to the Advanced Range Telemetry (ARTM) Tier I waveform, Feher’s Quadrature Phase Shift Keying, B
version (FQPSK-B) revision (Rev) A1. Also considered is another variant, FQPSK-JR. This paper
will outline the cross compatibility and resynchronization speed of these waveforms based upon
ARTM-adopted demodulator performance tests. The results of these laboratory tests comparing the
HYPERMOD demodulator, the enhanced Tier I demodulator, and the current Tier I reference
demodulator, both from RF Networks, will be presented.
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