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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nonlinear dynamics of systems involving widely spaced frequencies /

Nayfeh, Samir Ali, January 1993 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 77-79). Also available via the Internet.
2

A comparison of two types of zero-crossing FM demodulators for wireless receivers

McNeal, Jeff D. 11 February 1998 (has links)
A comparison of two novel demodulators. The first is a basic zero crossing demodulator, as introduced by Beards. The second is an approach proposed by Hovin. The two demodulators are compared to each other and to the conventional method of demodulation. / Graduation date: 1998
3

Reduction of power supply EMI emission by switching frequency modulation /

Lin, Feng, January 1992 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 66-67). Also available via the Internet.
4

Digital frequency demodulation for a laser vibrometer /

Cronin, Christopher Joseph. January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaf 75). Also available via the Internet.
5

Signal detection and enhancement of infrasound events

Schuette, Mark Louis January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
6

The RMS phase error of a phase-locked loop FM demodulator for standard NTSC video

Dubbert, Dale F January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Electrical and Computer Engineering.
7

Demodulator techniques in satellite communications systems for direct broadcast systems.

Marzolini, Remo G. A. January 1995 (has links)
Thesis (PhD)-Open University. BLDSC no.DX190076.
8

Nonlinear dynamics of systems involving widely spaced frequencies

Nayfeh, Samir Ali 30 June 2009 (has links)
This document focuses on the dynamics of nonlinear oscillatory systems involving widely spaced frequencies. First, experiments on the forced oscillations of a cantilever beam with a circular cross-section are presented. The beam is excited near its fifth natural frequency but sustained large-amplitude oscillations of the first mode accompanied by modulated oscillations of the fifth mode occur. Thus, energy is transferred from the fifth to the first mode of the beam, whose natural frequencies are roughly in the ratio of 60:1. Some simple two-degree-of-freedom systems are studied in an effort to explain the strong nonlinear coupling between modes with widely spaced frequencies. In these systems, the coupling is found to give rise to some novel phenomena including static displacements or sustained oscillations of the low-frequency mode in response to a high-frequency excitation. The possibility that resonances may occur between a high-frequency excitation and a single low-frequency mode is then investigated. A single-degree-of-freedom oscillator driven at a frequency much higher than its natural frequency is analyzed. It is found that, if the excitation is modulated, resonant excitation of the oscillator may occur. / Master of Science
9

Digital frequency demodulation for a laser vibrometer

Cronin, Christopher Joseph 10 November 2009 (has links)
This thesis presents the design and simulation of a digital frequency demodulator applied to a Michelson interferometer-based scanning laser vibrometer. The laser vibrometer is a velocity transducer that produces frequency-modulated signals that have traditionally been optically or electronically frequency shifted from baseband to an intermediate frequency. This shifting produces a narrow band modulation that may be demodulated with standard analog frequency demodulators. This thesis proposes replacing these traditional optics or electronic circuits with a digital frequency demodulator. The optics of a laser vibrometer can be constructed such that a near-perfect baseband quadrature representation is available for the frequency modulation. It will be seen that this representation is well suited for use by a digital frequency demodulator. This thesis applies the arctangent-type digital frequency demodulator to a laser vibrometer and demonstrates its superiority over other digital demodulation techniques. In addition some specialized signal processing to handle the special case of sine-dwell vibration tests is presented. / Master of Science
10

Reduction of power supply EMI emission by switching frequency modulation

Lin, Feng 22 August 2009 (has links)
The effect of PWM frequency modulation on power supply conducted EM! noise emission is investigated. Significant reduction of emission is possible with PWM frequency modulation scheme. A forward converter is used to verify the effectiveness of the scheme. A guidance of parameter selection for noise reduction is given. / Master of Science

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