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A crystal oscillator is an electronic oscillator circuit that uses a piezoelectric crystal as a frequency-selective element. [1] [2] [3] The oscillator 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.
In electrical engineering, and particularly in telecommunications, frequency drift is an unintended and generally arbitrary offset of an oscillator from its nominal frequency. Causes may include component aging, [ 1 ] changes in temperature that alter the piezoelectric effect in a crystal oscillator , or problems with a voltage regulator which ...
An OCXO inside an HP digital frequency counter Miniature crystal oven used to stabilize the frequency of a vacuum-tube mobile radio transmitter. 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.
Crystal oscillators can be manufactured for oscillation over a wide range of frequencies, from a few kilohertz up to several hundred megahertz.Many applications call for a crystal oscillator frequency conveniently related to some other desired frequency, so hundreds of standard crystal frequencies are made in large quantities and stocked by electronics distributors.
A tri-tet oscillator is a crystal-controlled vacuum tube electronic oscillator circuit. It is a type of electron-coupled oscillator (ECO), which uses a tetrode or pentode tube. The tri-tet was introduced by James J. Lamb in the June 1933 issue of QST magazine. [1] In an ECO, the screen grid acts as a plate for the triode oscillator.
Due to the sub 1 ppm accuracy of this type of crystal oscillator specialist packaging must be used to ensure good ageing and temperature shock characteristics. Example applications are for use in low power or battery operated consumer electronic products such as GSM or CDMA mobile phones, or GPS satellite navigation systems.
An oscillator start-up timer (OST) is a module used by some microcontrollers to keep the device reset until the crystal oscillator is stable. When a crystal oscillator starts up, its frequency is not constant, which causes the clock frequency to be non-constant. This would cause timing errors, leading to many problems. An oscillator start-up ...
The total capacitance seen from the crystal looking into the rest of the circuit is called the "load capacitance". When a manufacturer makes a "parallel" crystal, a technician uses a Pierce oscillator with a particular fixed load capacitance (often 18 or 20 pF) while trimming the crystal to oscillate at exactly the frequency written on its package.