A Digital Technique for Temperature Compensation of Crystal Oscillators PDF Download

Author: G. A. Warwick
Publisher:
ISBN:
Category :
Languages : en
Pages :

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

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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. Dominguez
Publisher:
ISBN:
Category :
Languages : en
Pages : 24

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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: T. Kudo
Publisher:
ISBN:
Category :
Languages : en
Pages : 6

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This paper describes a new frequency temperature compensation method for crystal oscillators. The method is applicable to resonators with second order or third order frequency temperature characteristics. Hence, an oscillator with an AT cut, a BT cut crystal unit or a surface acoustic wave resonator (SAWR) can be efficiently compensated. A conventional temperature compensated crystal oscillator (TCXO) uses an expensive variable capacitance diode (varactor) with good linearity as well as many thermistors. Considerable efforts have been devoted to developing a new reactance circuit to replace the varactor. It was found that a series circuit, involving a capacitor and a silicon diode, has the same characteristics as a varactor, and its linearity could be easily adjusted. In the case of an AT cut crystal unit with third order frequency temperature characteristics, compensation over a wide temperature range can be achieved by using two series circuits.

Author: BENDIX CORP DAVENPORT IA PIONEER-CENTRAL DIV.
Publisher:
ISBN:
Category :
Languages : en
Pages : 36

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A computer program is presented that was successfully used to determine thermistor-resistor compensation networks. Examples are given and results of synthesizing a number of compensation networks are given. The computer program will solve for the thermistor-resistor values in the compensation network, the R1/R2 ratio of the network at all temperatures of interest; the error in R1/R2 of the synthesized network compared to the required R1/R2 ratio; and the resultant expected frequency error at each temperature. (Author).

Author: J. S. Wilson
Publisher:
ISBN:
Category :
Languages : en
Pages : 6

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A new method of temperature compensation of crystal oscillators has been developed. It is primarily intended for AT-cut crystal oscillators and offers advantages of higher stability, lower power consumption and smaller size compared with oscillators in current production. Compensation is achieved by generating a power series representation of the control voltage for a voltage controlled crystal oscillator. A bipolar integrated circuit has been designed which generates four voltages, each varying as a function of temperature. One voltage is constant while the others have a linear, quadratic and cubic variation with temperature. These voltages are similar in shape to the first four Chebyshev polynomials and the compensation voltage is obtained by summing the voltages in an operational amplifier. Prototype oscillators have been assembled which have a frequency tolerance of less than + or - 1ppm over the temperature band 85 deg C to -40 deg C. The current consumption of these oscillators is 1mA. (Author).

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

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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: Darrell E. Newell
Publisher:
ISBN:
Category :
Languages : en
Pages : 78

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The first section of the report discusses a new hybrid voltage regulator which is housed in a TO5 container. The regulator was specifically designed for utilization by TCXOs and consequently, contains desirable feature for this use. The second phase of the investigation covers the generation of various temperature environments. A ramp generator and interval generator have been developed. Temperature ramps have been generated at slopes varying from 6.165 to 0.057 C/min. The third section of the report covers a study of isolation amplifiers. Since TCXO size is of importance, it is desirable to use as few stages as possible. Consequently, if an isolation amplifier can be used to provide both isolation and some degree of gain satisfactorily, it may be possible to omit one gain stage. (Author).

Author: Nicolo Testi
Publisher:
ISBN:
Category :
Languages : en
Pages : 250

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

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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.