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Frequency drift

About: Frequency drift is a research topic. Over the lifetime, 5054 publications have been published within this topic receiving 56191 citations. The topic is also known as: chirp rate.


Papers
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Journal ArticleDOI
TL;DR: A micro-power circuit is encapsulated with a 2.1 MHz ZT-cut quartz in a vacuum package that allows to achieve ±2 ppm frequency stability down to 1.8 V with a current under 0.5 ¿A.
Abstract: A micropower crystal oscillator module for watch applications is presented. The integrated circuit is encapsulated with a 2.1-MHz crystal in a miniature vacuum package to reduce parasitic effects. The circuit comprises frequency tuning with a resolution of /spl plusmn/3 s/year ~/spl plusmn/0.1 parts per million (ppm)\ and auxiliary circuits. A single output delivers a signal of 16 384 Hz with a frequency stability of /spl plusmn/2 ppm over the temperature range (-10 to 70/spl deg/C). The oscillator core has two complementary active MOSFET's and amplitude stabilization in order to get both low power consumption and high stability. New coupling and biasing circuits between the oscillator and the dynamic frequency dividers allow to achieve a current consumption under 0.5 /spl mu/A for a supply voltage between 1.8 and 3.5 V.

36 citations

Patent
18 Apr 1996
TL;DR: In this paper, an optical comb generator is used to determine the frequency component of a test light source by means of a superheterodyne receiver, and the frequency comb of the comb generator may be displaced as a whole and/or have its spectral width modified.
Abstract: An optical frequency generator has an optical comb generator (1) with which because of optical non-linearities around a central frequency a plurality of sidebands may be generated whose frequency spacing is given by the sending frequency of a frequency sender (13) supplied to the comb generator (1) The central frequency is adjustably coupled by a superheterodyne unit (6) to the spectral component of a reference light source (8) By modifying the frequency difference between the reference light source (8) and the central frequency of the comb generator (1) and by modifying the sending frequency of the frequency sender (13), the frequency comb of the comb generator (1) may be displaced as a whole and/or have its spectral width modified The optical frequency generator is appropriately used to determine the frequency component of a test light source (15) by means of a superheterodyne receiver (17)

36 citations

Patent
07 Jun 2001
TL;DR: In this article, a circuit and method for a multi-phase voltage-controlled LC oscillator are presented, where the oscillator is configured as a ring containing N sections, each of which has an LC tank circuit that determiines the oscillation frequency.
Abstract: A circuit and method are disclosed herein for a multi-phase voltage-controlled LC oscillator. The oscillator is configured as a ring containing N sections, each of which has an LC tank circuit that determiines the oscillation frequency. All the oscillator sections produce a signal at the same frequency, but with a constant phase angle offset between one section and the next. Thus, for example, a 4-phase version of the oscillator would have 4 sections, producing signals with phase angles of 0°, 90°, 180°, and 270°. The phase offset in each section results from the use of amplified quadrature signals to drive the LC circuits. An advantage of this approach to obtaining multiple phases is enhanced frequency stability, since the LC circuits in the oscillator sections all operate at resonance. Frequency modulation is accomplished without the use of varactors or other voltage-controlled tuning devices. Instead, a quadrature current summed into the LC tank circuit of each section increases or decreases the resonant frequency. A transconductance amplifier regulates the quadrature current, so the oscillation frequency can be controlled using an external voltage.

36 citations

Patent
03 Mar 1994
TL;DR: In this article, a mixer is provided having a mixing element, an input signal port for incoming signals at a frequency fIN, a local oscillator signal port, and an output port from which the resultant frequency may be taken.
Abstract: A mixer is provided having a mixing element, an input signal port for incoming signals at a frequency fIN, a local oscillator signal port for signals from a local oscillator having a fundamental frequency fLO, and an output port from which the resultant frequency may be taken. Means are provided to impose a DC component of bias voltage across the mixing element at one of three levels. The mixer is such that it has a pair of conduction threshold voltages which are substantially symmetrical above and below zero volts, beyond which the mixing element will be conductive at least when a signal from the local oscillator is imposed on it. The signal from the local oscillator has substantially sinusoidal voltage waveform, with a peak-to-peak voltage which is greater than the voltage difference between the pair of conduction threshold voltages. When the first zero DC component bias voltage is imposed across the mixer element, the mixing element is conductive in respective symmetrical positive-going and negative-going senses, and the maximized resultant frequency is |fIN ±2fLO |. When the second DC component of bias voltage is imposed across the mixing element, it conducts only once per cycle of local oscillator voltage, so that the maximized resultant frequency is |fIN ±fLO |. When the third DC component of bias voltage is imposed across the mixing element, the value of voltage across the mixing element exceeds the threshold voltage in the same sense as the voltage shift for about 35% to about 55% of the period of the local oscillator voltage cycle making the mixer conductive, but it is also conductive in the opposite sense for at least a portion of the remaining period of the cycle, so that third harmonic mixing occurs, and the maximized resultant frequency is |fIN ±3fLO |.

36 citations

Journal ArticleDOI
TL;DR: In this paper, the results of radio telescope UTR-2 observations of solar Type II radio bursts in the 10-30-MHz frequency range are presented, which possess a fine structure consisting of fast drift sub-bursts similar to Type II bursts.
Abstract: We present the results of radio telescope UTR-2 observations of solar Type II radio bursts in the 10–30 MHz frequency range. These events possess a fine structure consisting of fast drift sub-bursts similar to Type III bursts. The frequency drift rate of the Type II bursts at decameter wavelengths is smaller than 0.1 MHz s−1. One of these bursts with herringbone structure has a wave-like backbone that almost does not drift. The features of the observed bursts are discussed.

35 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202217
202150
202059
201963
201887