These can be thin metal pieces, or they can be electroplated contact surfaces. The assembly is then placed in an enclosure often metal to physically protect it and reduce the effect of electrical interference, Figure 4. A: By precision grinding and polishing, just as a glass lens would be. For many years this was done by hand by skilled craftspeople; now it is automated, of course, with the preparation and measurement done simultaneously.
A: There are many, of course: initial frequency of resonance, accuracy of that frequency, start-up time, phase noise jitter , short-term stability drift , and long-term stability drift are among the key ones. Many specifications are presented in parts per million ppm or percentage: 0. A: Like all mechanical components, quartz blanks change slightly but meaningfully with temperature. Therefore, a shift in ambient or operating temperature of even a few degrees will change their natural resonance and thus their key attributes.
Part 2 of this FAQ will discuss the performance of crystal-based oscillators and what can be done to get higher performance, as well as maintain initial accuracy over time and temperature. These factors are critical to the performance of the circuit and application. There are countless technical papers, treatises, application notes, vendor tutorials, and other support material available thus very important topic.
Some are highly readable and applicable, while others take a dive deep into basic physics this does not mean there are of little use; they are very useful. Among the many are these:. You may also like: Quartz crystals and oscillators, Part 2: Advanced crystals What is a clock and what are its critical parameters… What is a clock and what are its critical parameters… Chip-scale atomic clocks fit in compact quarters Clock Tree It all depends on how you cut it.
Quartz oscillators have a very high Q factor, which means that it takes them much longer to lose energy. All oscillators, no matter which one you use, are going to have some phase noise. Phase noise is another way to discuss the amount of jitter on a frequency. The idea is to have a smooth frequency wave with tiny variations. The high Q factor of a quartz oscillator helps to lower the phase noise and keep everything running perfectly. This is especially important for people using a quartz crystal oscillator for their radio frequencies.
Are you convinced that quartz crystal is what you need for your next project? For your viewing pleasure, he is also imaged below. Side thought: I wonder what he was thinking about at the time of this photo nearly years ago. While quartz resonators were used for sonar in World War I, one of the first major uses for quartz crystal oscillators was improving radio broadcasts. Quartz crystal oscillators were developed for high-stability frequency references during the s and s.
Before crystals were used, radio stations controlled their frequency with tuned circuits, which could easily drift off frequency by 3—4 kHz. Broadcast stations were assigned frequencies only 10kHz apart, so it was common to experience some overlap between stations due to frequency drift.
The frustration this caused was probably similar to how you feel when you experience slow wifi By , quartz crystals were used to control the frequency of many broadcasting stations and were popular with amateur radio operators.
Thanks to a crystal oscillator's ability to maintain strong frequency stabilization , this solved the problem of frequency drift between stations and allowed for a better listening experience.
Discover Bliley's Ultra-Stable Oscillators. Q uartz clocks replaced precision pendulum clocks and became the world's most accurate timekeepers. That is Crystal Shortages and the Rise of Synthetic Crystals. Through World War II, crystals and oscillators were used with all natural quartz crystals. However, WWII triggered a major increase in demand for quartz crystals because of the need for frequency control in military devices such as radios and radar.
This high demand sparked postwar research into developing synthetic quartz crystals to keep up with higher demands. By a hydrothermal process for growing quartz crystals on a commercial scale was developed at Bell Laboratories. By the s just about all crystals used in electronics were synthetic. Want to see what today's most innovative frequency control technology is all about?
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