Publication Date


Document Type


First Advisor

Newell, Darrell E.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Technology


Oscillators; Crystal


High performance temperature compensated crystal oscillators that provide low power precision timekeeping for new communication, navigation, surveillance, and identification friend/foe systems under development are unavailable at this time. However, the advent of low power integrated circuitry has initiated the development of higher stability TCXO. The traditional TCXO incorporating this new technology still suffers from inherent limitations associated with the traditional approach. This thesis proposes a method of externally temperature compensating a crystal oscillator, consequently minimizing the limitations plaguing the traditional approach. The concept is formulated around the ability of combining two different frequency sources together, yielding a single frequency source equal to the frequency sum of the two signals. One of the signals is an uncompensated crystal oscillator with the other signal being the difference between the desired output and the uncompensated oscillator's frequency. A single sideband mixer is used to accomplish the frequency addition. The low frequency compensation signal is generated with the aid of a programmable divider, which is controlled by a microprocessor. Spectral purifying of the compensated signal is accomplished with a phase lock loop filter. The single sideband concept was shown to be a viable means for externally compensating a crystal oscillator. Introduction of a single sideband mixer and a phase lock clean-up loop provides the ECXO with a sinewave output capability extending its usefulness to frequency control as well as timekeeping applications.


Bibliography: pages [165]-167.


xii, 182 pages




Northern Illinois University

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