Crystal oscillator

related topics
{system, computer, user}
{math, energy, light}
{acid, form, water}
{@card@, make, design}
{rate, high, increase}
{math, number, function}
{mi², represent, 1st}
{war, force, army}

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 very precise frequency. This frequency is commonly 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 most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits designed around them became known as "crystal oscillators."

Quartz crystals are manufactured for frequencies from a few tens of kilohertz to tens of megahertz. More than two billion (2×109) crystals are manufactured annually. Most are small devices for consumer devices such as wristwatches, clocks, radios, computers, and cellphones. Quartz crystals are also found inside test and measurement equipment, such as counters, signal generators, and oscilloscopes.

Contents

History

Piezoelectricity was discovered by Jacques and Pierre Curie in 1880. 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[1] in 1918 by Alexander M. Nicholson at Bell Telephone Laboratories, although his priority was disputed by Walter Guyton Cady.[2] Cady built the first quartz crystal oscillator in 1921.[3] Other early innovators in quartz crystal oscillators include G. W. Pierce and Louis Essen.

Full article ▸

related documents
Communications satellite
Charge-coupled device
Liquid crystal display
Optical amplifier
Ground (electricity)
Loading coil
Three-phase electric power
Spread spectrum
Pulse-width modulation
Cathode ray tube
Power factor
Jitter
Insulated-gate bipolar transistor
Multiplexing
Amateur radio
Server (computing)
Micro Channel architecture
Squelch
Communications protocol
Dolby noise reduction system
Universal Disk Format
Commodore PET
Package management system
Magnetic core memory
Zilog Z80
Windows 95
High-Level Data Link Control
E-mail client
Trillian (software)
Videotape