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
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/45633 |
| Date | 10 November 2009 |
| Creators | Cronin, Christopher Joseph |
| Contributors | Electrical Engineering, West, Robert L. Jr., Wicks, Alfred L., Abbott, A. Lynn |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | vi, 76 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 30830803, LD5655.V855_1994.C766.pdf |
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