Ad
related to: quartz resonance frequency
Search results
Results From The WOW.Com Content Network
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.
Frequencies also used are 8.6436 MHz and 17.2872 MHz. 4.332 RDS: 3648× the RDS signal bit rate of 1187.5 bit/s. While the frequency of 4.332 MHz is the most commonly used crystal resonator, its multiples (2×4.332 MHz = 8.664 MHz or 4×4.332 MHz = 17.328 MHz) have been used also. 4.43361875 PAL/NTSC: PAL B/D/G/H/I and NTSC M4.43 color subcarrier.
Quartz has a further advantage in that its size does not change much as temperature fluctuates. Fused quartz is often used for laboratory equipment that must not change shape along with the temperature. A quartz plate's resonance frequency, based on its size, will not significantly rise or fall.
Quartz is one member of a family of crystals that experience the piezoelectric effect.The piezoelectric effect has found applications in high power sources, sensors, actuators, frequency standards, motors, etc., and the relationship between applied voltage and mechanical deformation is well known; this allows probing an acoustic resonance by electrical means.
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:
The high dimensional stability and low temperature coefficient of quartz helps keeps resonant frequency constant. In addition, the quartz's piezoelectric property converts the mechanical vibrations into an oscillating voltage , which is picked up by the attached electrodes.
During early studies and experimentation phase of thin film resonators in 1967 cadmium sulfide (CdS) was evaporated on a resonant piece of bulk quartz crystal which served as a transducer providing a Q factor (quality factor) of 5000 at the resonance frequency (279 MHz). [15]
The Q factor is a parameter that describes the resonance behavior of an underdamped harmonic oscillator (resonator). Sinusoidally driven resonators having higher Q factors resonate with greater amplitudes (at the resonant frequency) but have a smaller range of frequencies around that frequency for which they resonate; the range of frequencies for which the oscillator resonates is called the ...