A Temperature Compensated SC Cut Quartz Crystal Oscillator PDF Download

Author: Edward K. Miguel
Publisher:
ISBN:
Category : Electronic circuits
Languages : en
Pages : 13

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Book Description
A method of temperature compensating a pullable Sc Cut quartz crystal is presented. The B and C modes of the SC Cut are resonated simultaneously. The B mode is used as a temperature sensor which has a linearity of -25 ppm/degrees C. The C mode is compensated using the temperature information from the B mode. A dual mode oscillator is developed which allows the frequency of the C mode to be controlled without affecting the B mode. A digital compensation method uses a RAM for on board information storage and programming. The address to the RAM is temperature generated and the output of the RAM is converted to a voltage to control the C mode oscillator. The compensation information is programmed automatically, during a temperature slew of 1.5 degrees C/min., using a phase-locked-loop, an up/down counter and a track-and-hold circuit all of which are connected to the oscillator only during the programming step.

Author: Marvin Frerking
Publisher: Springer Science & Business Media
ISBN: 9401160562
Category : Science
Languages : en
Pages : 252

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Book Description
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.

Author: C. D. DOMINQUEZ
Publisher:
ISBN:
Category :
Languages : en
Pages : 87

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Book Description
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).

Author: O. J. Baltzer
Publisher:
ISBN:
Category :
Languages : en
Pages : 69

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Book Description
The primary objective of this contract was an investigation and exploratory development of an externally compensated crystal oscillator (EXCO) in which frequency-temperature compensation of the C-mode frequency of an SC-cut quartz crystal is achieved by utilizing the concurrent B-mode frequency as a highly sensitive digital temperature sensor. The digitized B-mode output, used in conjunction with a microcomputer and a stored frequency/temperature look-up table or a suitable compensation algorithm, is able to provide precise and accurate clock corrections over a much wider range than that possible with a conventional TCXO oscillator (a temperature compensated oscillator which employs a voltage-variable capacitor for direct oscillator frequency control).

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
The purpose of this project is to evolve a practical approach to the temperature compensation of quartz crystal oscillators. The study will be concentrated on a nominal frequency of five megacycles, but will be generally applicable to AT cut quartz crystals of from 1 to 20 megacycles. The use of graphical analysis for TCXO design is discussed. The results of this investigation show that a graphical analysis will not be useable for very accurate compensation because of resolution and parameters that cannot be taken into account with graphs. The techniques for determining compensation networks are discussed. A new technique is described where diodes are used in conjunction with thermistor-resistor networks. The 5 x 10 to the minus 8th power, Group III, TCXO's are discussed. Results of the first compensation attempts are given. The compensation networks and techniques used are presented. (Author).

Author: Richard H. Bangert
Publisher:
ISBN:
Category :
Languages : en
Pages : 96

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Book Description
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).

Author: Ramon M. Cerda
Publisher: Artech House
ISBN: 1608071189
Category : Technology & Engineering
Languages : en
Pages : 325

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Book Description
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.

Author: C. D. Dominguez
Publisher:
ISBN:
Category :
Languages : en
Pages : 24

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Book Description
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).

Author: Arthur Ballato
Publisher:
ISBN:
Category :
Languages : en
Pages : 62

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Book Description
Resonators for TCXO application are required to have accurately-characterized frequency-temperature (f-T) curves and equivalent network parameters. This report describes how the circuit parameters, critical resonator frequencies, and temperature coefficients depend on material constants of the crystal and geometrical factors. These constants are tabulated for AT- and SC-cut quartz. It further explains the observed f-T curve shift between resonator operation with and without series load capacitors. Simple relations are given for treating this effect, along with charts and other design aids. These are used in a practical example involving an AT-cut resonator for a typical TCXO application. (Author).

Author: Darrell E. Newell
Publisher:
ISBN:
Category :
Languages : en
Pages : 107

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Book Description
The purpose of the project was to advance frequency temperature compensation techniques for stabilities of plus or minus 2 x 10 to the minus 7th power (Group 1) and plus or minus 5 x 10 to the minus 8th power (Group 2) over their operating ambient temperature ranges. It is the object of the work to simplify frequency temperature compensation networks and associated compensation procedures such as to realize a significant unit cost reduction. The report discusses the crystal specification selected. The difficulties encountered with the network voltage-temperature retrace, are discussed. A schematic and test results of a special test unit are shown. General performance on sample units are also discussed. A general segmented network compensation procedure is included. (Author).