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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.
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.
It is also possible for quartz clocks and watches to have their quartz crystal oscillate at a higher frequency than 32 768 (= 2 15) Hz (high frequency quartz movements [4]) and/or generate digital pulses more than once per second, to drive a stepping motor powered second hand at a higher power of 2 than once every second, [5] but the electric ...
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (one decimeter).
In particular, quartz crystals can exhibit mechanical resonances with a very high Q factor (from 10,000 to 100,000 and greater – far higher than conventional resonators built from inductors and capacitors). The crystal's stability and its high Q factor allow crystal filters to have precise center frequencies and steep band-pass characteristics.
In 2010, Miyota (Citizen Watch) of Japan introduced a newly developed movement that uses a new type of quartz crystal with ultra-high frequency (262.144 kHz) which is claimed to be accurate to +/- 10 seconds a year, and has a smooth sweeping second hand rather than one that jumps. [46]
With the development of thin film technologies it was possible to keep the Q factor high enough, leave out the crystal and increase resonance frequency. Ladder type bandpass filter based on FBAR resonators. The difference of resonance frequency of resonators 1 and 2 determine the frequency range of frequencies to be passed.
The Sauerbrey equation was developed for oscillation in air and only applies to rigid masses attached to the crystal. It has been shown that quartz crystal microbalance measurements can be performed in liquid, in which case a viscosity related decrease in the resonant frequency will be observed: