Current Search: Quartz crystals (x)
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Title
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PRECISION TC SYSTEM FOR MEASURING ACTIVITY DIPS OF QUARTZ CRYSTALS.
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Creator
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Peterson, Vance Howard, Florida Atlantic University, Graham, Peter, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
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Abstract/Description
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There is an increasing market demand for quartz crystals which exhibit minimal activity dip or frequency anomalies over a predefined temperature range. Characterization of the frequency vs temperature (f-T) activity dip profiles of these tight tolerance crystals is best carried out using a system which has been expressly designed for such a purpose. Frequency measurement accuracy and reliable temperature control must be established in the system, along with its being compatible with a...
Show moreThere is an increasing market demand for quartz crystals which exhibit minimal activity dip or frequency anomalies over a predefined temperature range. Characterization of the frequency vs temperature (f-T) activity dip profiles of these tight tolerance crystals is best carried out using a system which has been expressly designed for such a purpose. Frequency measurement accuracy and reliable temperature control must be established in the system, along with its being compatible with a computer controlled production or engineering enviornment. This thesis will present design and implementation details for a system with the aformentioned objective of enabling the generation of accurate crystal activity dip data. The system will provide the user with up-to-date facilities for meeting the temperature testing requirements of tight tolerance crystals.
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Date Issued
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1986
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PURL
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http://purl.flvc.org/fcla/dt/14343
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Subject Headings
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Quartz crystals, Oscillators, Crystal
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Format
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Document (PDF)
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Title
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Acceleration charge sensitivity in AT-quartz resonators.
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Creator
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Anderson, Clifford L. H., Florida Atlantic University, Bagby, Jonathan S.
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Abstract/Description
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The behavior of AT-quartz resonators subject to acceleration is studied. For an AT strip resonator with cantilever mounting, piezoelectric theory predicts that excitation of the pure lowest frequency flexural mode of vibration generates no charge. However, experiments show electromechanical resonance corresponding to this mode for sinusoidal support motion normal to the plane of the crystal with no applied electric field. An amplifier with a voltage follower first stage senses charge output...
Show moreThe behavior of AT-quartz resonators subject to acceleration is studied. For an AT strip resonator with cantilever mounting, piezoelectric theory predicts that excitation of the pure lowest frequency flexural mode of vibration generates no charge. However, experiments show electromechanical resonance corresponding to this mode for sinusoidal support motion normal to the plane of the crystal with no applied electric field. An amplifier with a voltage follower first stage senses charge output from the crystal. Shielding is required to reduce sixty hertz and drive frequency electromagnetic interference. Measurement of resonant frequency and damping factor for the lowest frequency flexural mode is reported for a group of 17.76 MHz oscillator crystals. This mode is responsible for crystal breakage in some portable communications products. Significant variation in sensitivity among crystals was observed. Charge sensitivity of this mode is attributed in part to mechanical coupling to other modes involving torsion and lateral flexure.
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Date Issued
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1995
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PURL
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http://purl.flvc.org/fcla/dt/15126
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Subject Headings
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Quartz crystals, Piezoelectricity, Oscillators, Crystal, Resonators, Acceleration (Mechanics)
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Format
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Document (PDF)