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5.4.7.5 Frequency Standards
Here quartz is most commonly used material as its piezoelectric properties are useful as standard of frequency.
Watches use a quartz tuning fork which uses a combination of both direct and converse piezoelectricity to give rise to a regularly timed series of electrical pulses that is used to mark time.
The quartz crystal has a very accurately defined natural frequency of vibration at which it prefers to oscillate, and this is used to stabilize the frequency of a periodic voltage applied to the crystal.
The same principle is critical in all radio transmitters and receivers, and in computers where it creates a clock pulse. Both of these usually use a frequency multiplier to reach the megahertz and gigahertz ranges. |
