The need for ovenless quartz crystal oscillators having a deviation less than = 0.75 parts per million from an absolute frequency over all service conditions, including crystal aging, has become evident for modern communications systems. Current knowledge derived from studies on frequency temperature compensation techniques indicate the feasibility of combating the difficulties associated with frequency compensated oscillators to produce a reduction in both power and size over conventional oscillatoroven assemblies. The object of Phase I of this program is to design and fabricate seven exploratory development oscillator models operating at 3 mc and employing such compensation techniques to achieve a stability requirement of less than = 0.5 ppm over the temperature range of -40C to +65C. After evaluation of these exploratory models, eighteen advanced models incorporating the revisions required will be fabricated under Phase II of this program. This report covers only the effort expended in Phase I of this program. The significant problem areas were related to (1) development of a voltage regulator with good regulation throughout the temperature range, (2) evolution of a standard compensation network, (3) limitations in the state-of-the-art of crystal technology, (4) low power input requirement of 65 milliwatts, and (5) development of a constant gain amplifier using high tolerance components. (Author).

The need for ovenless quartz crystal oscillators having a deviation less than plus or minus 0.75 parts per million from an absolute frequency over all service conditions, including crystal aging, has been evident for modern communications systems. Knowledge derived from studies on frequecy temperature compensation techniques indicated the feasibility of developing compensated oscillators providing a reduction in both required input power and size over conventional oscillator-oven assemblies. The object of Phase I of this program was to design and fabricate seven exploratory development oscillator models employing such compensation techniques to achieve a frequency stability of less than plus or minus 0.5 ppm over the temperature range of -40C to +65C. This effort was reported in the Phase I Interim Report under this contract. After evaluation of these exploratory models, 18 advanced models were designed and fabricated under Phase II of this program with the same stability over 140C to +75C. This report covers the effort expended and the results obtained during Phase II of this program. The discussion in this report is related to (1) description and test of the Phase II oscillators, (2) design considerations in formulation of Phase II design, (3) component standardization, and (4) overall conclusions and recommendations for this program. (Author).

Crystal oscillators have been in use now for well over SO years-one of the first was built by W. G. Cady in 1921. Today, millions of them are made every year, covering a range of frequencies from a few Kilohertz to several hundred Mega hertz and a range of stabilities from a fraction of one percent to a few parts in ten to the thirteenth, with most of them, by far, still in the range of several tens of parts per million.Their major application has long been the stabilization of fre quencies in transmitters and receivers, and indeed, the utilization of the frequency spectrum would be in utter chaos, and the communication systems as we know them today unthinkable,'without crystal oscillators. With the need to accommodate ever increasing numbers of users in a limited spectrum space, this traditional application will continue to grow for the fore seeable future, and ever tighter tolerances will have to be met by an ever larger percentage of these devices.

The purpose of this program was to advance circuit techniques for a new class of ovenless crystal oscillators having frequency temperature stabilities previously achieved in temperature stabilized oscillators consuming several watts of power. Two basic approaches to obtain computer optimized component values for a compensation network required to generate a desired non-linear voltage function, and hence achieve the desired degree of stability, are presented. Two groups of oscillator units, one group built to achieve a design goal frequency stability of + or -1 x 10 to the minus 7th power over the ambient temperature range of -40 C to +75 C and the other group built to achieve a design goal frequency stability of + or -5 x 10 to the minus 8th power over the ambient temperature range of -5 C to approximately +85 C, are discussed. (Author).

Frequency reference oscillator is a critical component of modern radio transceivers. Currently, most reference oscillators are based on low-frequency quartz crystals that are inherently bulky and incompatible with standard micro-fabrication processes. Moreover, their frequency limitation (200MHz) requires large up-conversion ratio in multigigahertz frequency synthesizers, which in turn, degrades the phase-noise. Recent advances in MEMS technology have made realization of high-frequency on-chip low phase-noise MEMS oscillators possible. Although significant research has been directed toward replacing quartz crystal oscillators with integrated micromechanical oscillators, their phase-noise performance is not well modeled. In addition, little attention has been paid to developing electronic frequency tuning techniques to compensate for temperature/process variation and improve the absolute frequency accuracy. The objective of this dissertation was to realize high-frequency temperature-compensated high-frequency (100MHz) micromechanical oscillators and study their phase-noise performance. To this end, low-power low-noise CMOS transimpedance amplifiers (TIA) that employ novel gain and bandwidth enhancement techniques are interfaced with high frequency (>100MHz) micromechanical resonators. The oscillation frequency is varied by a tuning network that uses frequency tuning enhancement techniques to increase the tuning range with minimal effect on the phase-noise performance. Taking advantage of extended frequency tuning range, and on-chip temperature-compensation circuitry is embedded with the sustaining circuitry to electronically temperature-compensate the oscillator. Finally, detailed study of the phase-noise in micromechanical oscillators is performed and analytical phase-noise models are derived.

The object of this handbook is to assemble a set of design methods for crystal oscillators in the frequency range of 1 KC to 200 MC with the aim of facilitating design, eliminating crystal unit misapplications, and reducing design costs. The handbook is not directed at the design of ultra-stable crystal oscillators, but rather at the non-temperature controlled, medium frequency stability oscillator commonly in use in many types of communications equipment. The handbook contains discussions of: (1) The electrical characteristics of crystal units, condition of usage, and methods of measurement. (2) Characteristics of tube and transistor amplifiers. (3) Characteristics of impedance transforming networks. (4) Detailed design information on series resonance and anti-resonance oscillators. (5) Design examples together with experimental evaluation data covering most of the 1 KC to 200 MC range. (Author).

Quartz, unique in its chemical, electrical, mechanical, and thermal properties, is used as a frequency control element in applications where stability of frequency is an absolute necessity. Without crystal controlled transmission, radio and television would not be possible in their present form. The quartz crystals allow the individual channels in communication systems to be spaced closer together to make better use of one of most precious resources -- wireless bandwidth. This book describes the characteristics of the art of crystal oscillator design, including how to specify and select crystal oscillators. While presenting various varieties of crystal oscillators, this resource also provides you with useful MathCad and Genesys simulations.