Crystal oscillator

crystalquartz oscillatorquartz crystalcrystal oscillatorscrystal controlledquartzcrystal-controlledcrystalsquartz crystalsoscillator
A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency.wikipedia
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Quartz clock

quartz watchquartzquartz movement
This frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers.
This crystal oscillator creates a signal with very precise frequency, so that quartz clocks are at least an order of magnitude more accurate than mechanical clocks.

Clock

clockstimepiecemechanical clock
Most are used for consumer devices such as wristwatches, clocks, radios, computers, and cellphones.
This object can be a pendulum, a tuning fork, a quartz crystal, or the vibration of electrons in atoms as they emit microwaves.

Clock signal

clock cycleclockclock cycles
This frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers.
The preeminent example of such complex chips is the microprocessor, the central component of modern computers, which relies on a clock from a crystal oscillator.

Walter Guyton Cady

Walter G. CadyWalter Cady
Paul Langevin first investigated quartz resonators for use in sonar during World War I. The first crystal-controlled oscillator, using a crystal of Rochelle salt, was built in 1917 and patented in 1918 by Alexander M. Nicholson at Bell Telephone Laboratories, although his priority was disputed by Walter Guyton Cady.
He was a pioneer in piezoelectricity, and in 1921 developed the first quartz crystal oscillator.

Pierre Curie

PierreCurie, PierreCurie
Piezoelectricity was discovered by Jacques and Pierre Curie in 1880.
Almost all digital electronic circuits now rely on this in the form of crystal oscillators.

Watch

wristwatchwatchesdigital watch
Most are used for consumer devices such as wristwatches, clocks, radios, computers, and cellphones.
In place of a balance wheel which oscillated at perhaps 5 or 6 beats per second, it used a quartz crystal resonator which vibrated at 8,192 Hz, driven by a battery-powered oscillator circuit.

G. W. Pierce

George Washington PierceGeorge W. PiercePierce, G. W.
Other early innovators in quartz crystal oscillators include G. W. Pierce and Louis Essen.
The most notable is the single-stage crystal oscillator circuit, which became the touchstone of the electronics communication art.

Transmitter

radio transmittertransmittersradio transmitters
This frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers.
An electronic oscillator circuit to generate the radio frequency signal. This usually generates a sine wave of constant amplitude called the carrier wave, because it serves to "carry" the information through space. In most modern transmitters, this is a crystal oscillator in which the frequency is precisely controlled by the vibrations of a quartz crystal. The frequency of the carrier wave is considered the frequency of the transmitter.

Crystal oven

ovenOCXOoven controlled crystal oscillators
For critical applications the quartz oscillator is mounted in a temperature-controlled container, called a crystal oven, and can also be mounted on shock absorbers to prevent perturbation by external mechanical vibrations.
A crystal oven is a temperature-controlled chamber used to maintain the quartz crystal in electronic crystal oscillators at a constant temperature, in order to prevent changes in the frequency due to variations in ambient temperature.

Alexander M. Nicholson

Paul Langevin first investigated quartz resonators for use in sonar during World War I. The first crystal-controlled oscillator, using a crystal of Rochelle salt, was built in 1917 and patented in 1918 by Alexander M. Nicholson at Bell Telephone Laboratories, although his priority was disputed by Walter Guyton Cady.
Alexander M. Nicholson was an American scientist, most notable for inventing the first crystal oscillator, using a piece of Rochelle salt in 1917 while working at Bell Telephone Laboratories.

Louis Essen

Other early innovators in quartz crystal oscillators include G. W. Pierce and Louis Essen.
He started work at the National Physical Laboratory (NPL) the following year, under D. W. Dye, investigating the potential of tuning forks and quartz crystal oscillators for precise time measurement.

Resonator

resonant cavityresonatorscavity resonator
The crystal oscillator circuit sustains oscillation by taking a voltage signal from the quartz resonator, amplifying it, and feeding it back to the resonator.
Another example is quartz crystals used in electronic devices such as radio transmitters and quartz watches to produce oscillations of very precise frequency.

Electronic oscillator

oscillatoroscillatorsaudio oscillator
Paul Langevin first investigated quartz resonators for use in sonar during World War I. The first crystal-controlled oscillator, using a crystal of Rochelle salt, was built in 1917 and patented in 1918 by Alexander M. Nicholson at Bell Telephone Laboratories, although his priority was disputed by Walter Guyton Cady. A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency.
*In a crystal oscillator circuit the filter is a piezoelectric crystal (commonly a quartz crystal).

Crystal

crystallinecrystalscrystalline solid
A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency.
Crystal oscillator

Quartz

rock crystalquartz crystalcitrine
The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators, but other piezoelectric materials including polycrystalline ceramics are used in similar circuits.
The quartz oscillator or resonator was first developed by Walter Guyton Cady in 1921.

Tuning fork

tuning forkstuning-forkDiapasons
Low-frequency crystals, such as those used in digital watches, are typically cut in the shape of a tuning fork.
The quartz crystal that serves as the timekeeping element in modern quartz clocks and watches is in the form of a tiny tuning fork.

Crystal filter

quartz crystalquartz crystal filter
Crystals are also used in other types of electronic circuits, such as crystal filters.
*Crystal oscillator

Radiation hardening

radiation-hardenedradiation hardenedradiation hardness
The impurities have a negative impact on radiation hardness, susceptibility to twinning, filter loss, and long and short term stability of the crystals.
The lattice damage influences the frequency of crystal oscillators.

Ceramic resonator

ceramic filterceramic
Although crystal oscillators still most commonly use quartz crystals, devices using other materials are becoming more common, such as ceramic resonators.
Crystal oscillator

Surface acoustic wave

SAW[8filters
Crystals for SAW devices are grown as flat, with large X-size seed with low etch channel density.
SAW resonators are used in many of the same applications in which quartz crystals are used, because they can operate at higher frequency.

Q factor

quality factorQQ'' factor
A major reason for the wide use of crystal oscillators is their high Q factor.
For an electrically resonant system, the Q factor represents the effect of electrical resistance and, for electromechanical resonators such as quartz crystals, mechanical friction.

Gallium phosphate

gallium(III) orthophosphategallium-orthophosphate
Crystals of gallium phosphate, langasite, langanite and langanate are about 10 times more pullable than the corresponding quartz crystals, and are used in some VCXO oscillators.
GaPO 4 has many advantages over quartz for technical applications, like a higher electromechanical coupling coefficient in resonators, due to this doubling.

Allan variance

Allan deviationbetter clocks
The short-term stability is measured by four main parameters: Allan variance (the most common one specified in oscillator data sheets), phase noise, spectral density of phase deviations, and spectral density of fractional frequency deviations.
When investigating the stability of crystal oscillators and atomic clocks, it was found that they did not have a phase noise consisting only of white noise, but also of white frequency noise and flicker frequency noise.

Mechanical filter

filtersmechanical filters
It was often used in mechanical filters before quartz.
Crystal oscillator

Frequency synthesizer

frequency synthesisfrequency synthesisersynthesized
Phase noise plays a significant role in frequency synthesis systems using frequency multiplication; a multiplication of a frequency by N increases the phase noise power by N 2 . A frequency multiplication by 10 times multiplies the magnitude of the phase error by 10 times.
Consequently, synthesizers use stable and accurate reference frequencies, such as those provided by crystal oscillators.