Current Search: Oscillators, Crystal (x)
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- Title
- Varactors, crystals, and their use in voltage controlled oscillators.
- Creator
- Fenton, Eliot Darrel., Florida Atlantic University, Ungvichian, Vichate
- Abstract/Description
-
This thesis investigates the characteristics of varactors and crystals that affect Q and therefore the frequency stability of a voltage controlled oscillator (vco) when employed in a one MHz to three hundred MHz frequency synthesizer. A low noise VHF crystal oscillator, a low noise common base UHF oscillator, and a low noise test set-up are described, built, and tested.
- Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14676
- Subject Headings
- Oscillators, Electric, Oscillators, Crystal
- Format
- Document (PDF)
- Title
- PRECISION TC SYSTEM FOR MEASURING ACTIVITY DIPS OF QUARTZ CRYSTALS.
- Creator
- Peterson, Vance Howard, Florida Atlantic University, Graham, Peter, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
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.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14343
- Subject Headings
- Quartz crystals, Oscillators, Crystal
- Format
- Document (PDF)
- Title
- Theory of and a novel approach to high-stability frequency control circuits.
- Creator
- Brunell, David J., Florida Atlantic University, Bagby, Jonathan S.
- Abstract/Description
-
Portable, wireless devices have become ubiquitous, and ever-increasing requirements of functionality and reliability are being placed upon these devices. There is a need to accommodate the oft-conflicting requirements of small size, low power consumption, low cost, and extremely accurate control of frequency. To address these RF design requirements, a comprehensive survey of existing frequency-control methods is presented, followed by a novel design which accomplishes a high degree of...
Show morePortable, wireless devices have become ubiquitous, and ever-increasing requirements of functionality and reliability are being placed upon these devices. There is a need to accommodate the oft-conflicting requirements of small size, low power consumption, low cost, and extremely accurate control of frequency. To address these RF design requirements, a comprehensive survey of existing frequency-control methods is presented, followed by a novel design which accomplishes a high degree of frequency accuracy through the use of direct digital synthesis and a software seeking algorithm. The proposed design can be implemented pursuant to the requirements of current and future portable wireless devices.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12819
- Subject Headings
- Frequency synthesizers, Automatic frequency control, Oscillators, Crystal
- Format
- Document (PDF)
- Title
- Acceleration charge sensitivity in AT-quartz resonators.
- Creator
- Anderson, Clifford L. H., Florida Atlantic University, Bagby, Jonathan S.
- Abstract/Description
-
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.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15126
- Subject Headings
- Quartz crystals, Piezoelectricity, Oscillators, Crystal, Resonators, Acceleration (Mechanics)
- Format
- Document (PDF)