Inside Frequency Control

What is a Swept Quartz Crystal?

Like many other things, radiation can impact a crystal oscillator's frequency. This is because radiation physically alters the quartz crystal inside the oscillator (changes position of weakly bound compensators that change the elastic constants of quartz). In some cases, radiation can even impact the crystal series resonance. The increase of resonance can be serious enough to cause the oscillator to stop oscillating if the crystal isn't radiation resistant. When a quartz crystal is manufactured to be radiation resistant, the crystal is referred to as a swept quartz crystal.

Ahh the mysterious OCXO. What the heck is an OCXO anyway? What's it good for? When should you use one in your electronic system design? These questions and more will all be answered in this post.

The development of crystal oscillators has literally changed the world. Technically that can (and is) said about many things. But think about it! Without crystal oscillators, we may have never seen precision timing in clocks, wide and clear radio broadcasts, or important communication methods within military and space programs.

Imagine how different our world might be without these now commonplace technologies. 

We can't possibly be the only intelligent life-forms in this infinite universe, can we? I mean, there's still plenty of exploring to do in our own solar system let alone nearby stars, our entire galaxy, and surrounding galaxies. Will our current deep space communication efforts, like Voyager 1, ever stumble across alien life so us humans can say, "Hi! We're here!"? Or will it take so long that our messages would be more like, "Hi! We were here!"? 

Let's explore some current communication efforts to make contact with aliens and how they work.

Bliley Technologies is proud to be partnered with PARC, the Palo Alto Research Center, a leading hub of innovation in a wide range of cutting-edge 21st-century technologies. PARC has deep expertise in the high-tech fields of big data, optoelectronics, semiconductors, large area electronics, model-based reasoning for AI, and is a pioneer in the field of ubiquitous and context-aware computing.

RF engineers are aware that temperature variations are the most significant factor contributing to frequency drift in crystal oscillators. Other variables affecting frequency output, such as humidity and pressure, can be easily alleviated with a hermetically sealed packaging of the crystal in a vacuum, or in an inert gas such as nitrogen. Controlling temperature for precise frequency output in a crystal oscillator circuit, however, requires a higher level of electronic RF design ingenuity. Enter... The Oven Controlled Crystal Oscillator (OCXO).

TCXO Performance Qualities

A standard TCXO has quite a few performance qualities. Some of the most common performance figures are summarized below:

While looking through the Bliley archives for material to write about for this new installment of Stories From The Bliley Vault, I discovered a very interesting set of two letters— one from a minister in South Africa from 1936 and another from an Army Colonel in 1942.

Unmanned vehicles have changed our world over the past 15 years, and continue to do so one battlefield, one site inspection, and one independent film at a time. Science fiction writers, engineers and military thinkers alike had envisioned robotic and autonomous warfighting machines for years, and in the early 21^st century, they became a viable and widely used option in warfare. But as they continue to advance and become less expensive, what does future hold for unmanned vehicles?