Topic
Crystal oven
About: Crystal oven is a research topic. Over the lifetime, 955 publications have been published within this topic receiving 10380 citations. The topic is also known as: oven-controlled crystal oscillator & OCXO.
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01 Jun 1983
TL;DR: In this article, the frequency and phase noise in quartz crystal resonators were studied as a function of the driving power of the crystal and the crystal's nonlinearities were found to increase phase fluctuations at low Fourier frequencies.
Abstract: : Frequency and phase noise in quartz crystal resonators are studied as a function of the driving power. At low power, where the crystal behaves linearly, 1/f fluctuations of the resonance frequency are observed. At medium power the nonlinearities of the crystal significantly increase the phase fluctuations at low Fourier frequencies. At high power, thermal instabilities and chaotic behavior occur characterized by the generation of high level white noise.
41 citations
TL;DR: In this article, a digitally compensated crystal oscillator is described, which provides a frequency stability of (/spl Delta/f)/f < 1.5 ppm for a temperature range of -40/spl deg/C to 90/spl dc/C compared to about /spl plusmn/20 ppm for noncompensated crystal oscillators.
Abstract: The base frequency of oscillators used in the Global System for Mobile Communication (GSM) network or Global Positioning System (GPS) receiver applications needs to be very stable with respect to temperature and supply-voltage variations. One approach to obtain extremely good frequency stability is the use of oven-stabilized crystal oscillators. With this kind of oscillator, a frequency stability versus temperature of a few ppb versus the standard temperature range can be achieved. In this paper, a digitally compensated crystal oscillator is described. The system provides a frequency stability of (/spl Delta/f)/f<1.5 ppm for a temperature range of -40/spl deg/C to 90/spl deg/C compared to about /spl plusmn/20 ppm for a noncompensated crystal. The core of the system is an application-specified integrated circuit (ASIC) fabricated in a standard 0.8-/spl mu/m CMOS process. The power consumption for the oscillator running at 13 MHz is 100 mW. The final device equipped with the ASIC, crystal blank, and a few external components fits into a 14/spl times/9/spl times/3 mm/sup 3/ package.
40 citations
01 Feb 1966
TL;DR: In this article, progress made in the field of quartz crystal units and quartz crystal controlled oscillators over the past few years is reviewed in general, but several accomplishments which are thought to be of special importance, are discussed in detail.
Abstract: The paper discusses progress made in the field of quartz crystal units and quartz crystal controlled oscillators over the past few years The field is reviewed in general, but several accomplishments which are thought to be of special importance, are discussed in detail These subjects include, among others, quartz vibrator characteristics and enclosures, modes of motion including the "trapped energy" concept and long-term drift (aging) of crystal units The characteristics of various types of oscillators are reviewed including temperature compensated and high precision types, and the problem of short-term stability of crystal controlled oscillators is discussed Precision oscillators are available today with a daily drift rate as low as a few parts in 1011and a short time stability better than a few parts in 1010for a time period of one millisecond
40 citations
Patent•
11 Jun 2001TL;DR: In this article, a frequency control circuit was proposed to control an oscillation amplitude of a crystal oscillator including a crystal resonator, a current source supplying a bias current, and an output transistor coupled to the crystal resonators and the current source.
Abstract: A circuit controls an oscillation amplitude of a crystal oscillator including a crystal resonator, a current source supplying a bias current, and an output transistor coupled to the crystal resonator and the current source. The circuit includes a peak detector for detecting a peak voltage of an output signal of the crystal oscillator, and a controller coupled to the peak detector and to the current source for controlling the current source in accordance with a difference between the peak voltage and a target voltage, the target voltage being set to be substantially equal to 2Vth, where Vth is a threshold voltage of the output transistor. A frequency control circuit controls a first switched-capacitor array and a second switched-capacitor array coupled to the crystal resonator, and alternately switches a unit capacitor in the first switched-capacitor array and a unit capacitor in the second switched-capacitor array based on a frequency control signal.
39 citations
Patent•
25 Jul 1986
TL;DR: In this paper, an improved gas density transducer which compares the resonant frequency of an enclosed, reference tuning fork crystal oscillator with the frequency of a detector tuning fork oscillator exposed to the surrounding gas is presented.
Abstract: An improved gas density transducer which compares the resonant frequency of an enclosed, reference tuning fork crystal oscillator with the resonant frequency of a detector tuning fork crystal oscillator exposed to the surrounding gas. The frequency of oscillation of the detector crystal oscillator exposed will vary in accordance with the gas density because of the motional resistance of the gas to vibrations of the tuning fork oscillator. The frequency of the detector oscillator can be compared to the frequency of the reference oscillator to determine the gas density.
38 citations