Welcome to the Crystal Oscillator Professor

This blog is about the nuts and bolts of time and frequency control, and especially about the details of crystal oscillators, which are particularly fascinating devices. This blog will explore how timing systems using crystal oscillators work, and how to use, specify and troubleshoot crystal oscillators, as well as tracking and discussing the exciting new developments in the field.

Unleashing the Mystery of Crystal Cuts

Distinguished Guest Professor: Bernd Neubig, AXTAL Consulting When faced with quartz crystal data sheets or catalogs, you inevitably are confronted with the term “crystal cut.” What is this all about? This article will serve to clarify the significance of crystal cuts in the performance of crystal oscillators. In the most common applications quartz crystals are used as a core element to generate a stable frequency. Besides the stability over time (so-called aging), the frequency stability vs. temperature is a primary factor. Therefore, from the early beginning, researchers have looked on the parameters which determine frequency stability over temperature. Quartz crystals…

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The MCXO Is Finally Ready for Space

The latest advances in radiation-hardened digital components have enabled the development of MCXOs that, for the first time, can replace larger, high-power-consuming OCXOs in low-earth orbit (LEO) New Space applications Introduction The last post in this series explored the benefits of microcomputer-compensated crystal oscillators (MCXOs) when compared to (oven-controlled) OCXOs. This post introduces the first MCXO that combines clever engineering design with rad-hardened digital components to qualify for New Space applications. Developing Space-Qualified MCXOs When developing MCXOs in the early 2000s, the space- and rad hard-level digital components needed were very expensive, which meant an MCXO space-level product would sell…

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Comparing OCXOs to MCXOs

Oven-controlled (OCXO) and microprocessor-controlled (MCXO) crystal oscillators each provide exceptional frequency stability over a wide temperature range, using very different approaches. Introduction This post will describe the technology behind OCXOs and MCXOs and delve into the Size, Weight and Power (SWaP) benefits provided by MCXOs. The next article in this series will introduce the first space-qualified MCXO for low-earth orbit (New Space) applications. Crystal Oscillator Stability All crystal oscillators are based on the very stable frequency vibrations of a piezoelectric quartz crystal resonator. Usually, the crystals and their associated circuitry are carefully designed and crafted so that the quartz crystal…

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MEMS vs. Crystal Oscillators: It’s All in the Application

Putting timing and frequency control technologies in their proper place Introduction Precision frequency control and timing are essential to all modern electronics technology. Almost every electronic device you can imagine depends on a precision clock; without precision oscillator clocks, all electronic communication would stop. This article compares the benefits of the latest precision clock technologies as they perform in different applications. The Evolution of Precision Clocks Introduced in the 1920’s, the quartz crystal oscillator has long been the workhorse amongst electronic timing devices.  A newer type of oscillator that has been in development since the 1960s and available in production…

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Crystal Oscillators 101

Quartz is relatively abundant in nature and easy to grow in a very pure form. What sets it apart from other piezoelectric crystals is that it can be made to vibrate in very controlled and stable ways. Thus, a properly fashioned quartz resonator can act as an ultra-stable mechanical frequency source that can be coupled to an electronic oscillator circuit.

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Does anybody really know what time it is? (Part 2)

Quantum physics took the mysteries of time to a whole other level. Is time continuous or discrete? Is there a minimum size of time duration, a sort of quantum of time? Is time fundamental or is it an emergent phenomenon, or is it an illusion? Many scientists now think that time is not fundamental but that it emerges out of nothingness. Of course, nothingness itself is being redefined. Completely empty space is now thought to be a quantum foam, with virtual particles popping into and out of existence randomly and continuously. When these virtual particles happen to interact with each…

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White Paper Maps Out Spacescape Challenges in XO Selection

This informative white paper describes how the regions of the spacescape from low-earth orbit to deep space affect the selection of crystal oscillators. Subscribe to The Crystal Professor blog and we'll send you a free copy.