Inside Frequency Control

You've probably heard of ultra-stable oscillators, but what are they good for? Just by the name, you can probably tell they're great for maintaining frequency stability in applications. But what specific applications require very high stability to perform optimally? 

In this blog, we'll discuss the top four applications for ultra-stable oven controlled crystal oscillators (OCXOs).

To make the long journey to earth's orbit or beyond, spacecrafts must be designed to have very precise functionality. Even simple vibrations during pre-launch transportation and powered flight can interfere with the spacecraft’s functionality. These simple vibrations come from many different sources and can inhibit the spacecraft from reaching its full potential.

Spacecraft engineers must also be concerned about very small vibrations, known as micro-vibrations, from a spacecraft’s own moving parts as it operates in orbit. Micro-vibrations are typically sinusoidal with the chance of some integer harmonics and random vibration being present.

In this blog, we'll discuss four of the most common sources of vibration and micro-vibration in satellites and spacecrafts, and how you can reduce or prevent them in your application. 

Swept quartz crystals are necessary in timing applications that require radiation resistance, but it's important to understand how they work and when you should use them. 

In this blog, we'll review what swept quartz crystals are, how they're manufactured, their common applications, and a common misconception about their benefits.

When it comes to NTP stratum levels and minimum performance requirements for digital network synchronization, there's definitely a lot to know. A standard first released in 1987 entitled "Synchronization Interface Standards for Digital Networks" from the American National Standards Institute (ANSI) lays out all the official information and requirements. 

With the advances of RF technology over the last many years, most modern spectrum analyzers can now automatically detect changes in phase noise levels (mostly of sine wave signals) measured in units of dBc or rads.

But it’s always a good idea for RF engineers to understand how modern spectrum analyzers measure integrated phase deviation. Or better yet, for them to understand how to optimize a spectrum analyzer’s measurements even further. Believe it or not, but many spectrum analyzer readings of phase noise can be significantly off.

Measuring phase noise deviations is easier than it sounds. All you really have to do is learn how to determine the Root Mean Square (RMS). This is done by calculating the ratio of power from the single-sideband (SSB) phase noise to the carrier.

Here’s the scary thing…

Even if you sit for hours upon hours trying to set a precise initial frequency of an oscillator, it’s still going to drift and the oscillator will not be able maintain that frequency over the full course of its use. In this post, you’ll learn the many sources of frequency instability and why an ultra-stable OCXO may be the fix-all solution.

What's the difference between Ka-band and Ku-band systems? In this article, we explore what they are,  what sets them apart, the advantages of each, and the design considerations you should keep in mind. 

Temperature variations are the most significant factor contributing to frequency drift in crystal oscillators.

Other variables that affect frequency output, such as humidity and pressure, can be alleviated easily with a hermetically sealed packaging of the crystal in a vacuum or in an inert gas, such as nitrogen. But controlling temperature for precise frequency output in a crystal oscillator circuit requires a higher level of electronic RF design ingenuity. Enter: the oven controlled crystal oscillator (OCXO).

In this post, we'll take a look at the three types of OCXOs available for RF engineers to meet individual design priorities such as frequency precision, warm-up time, crystal aging, and power consumption.

The #1 Most Critical Factor in High-End Radar & Communication Systems: Low Phase Noise

Phase noise, phase noise, phase noise.

If you’re involved with the design and implementation of communication systems, you most likely hear the term “phase noise” all the time (maybe more times than you’d like). 

There’s a good reason for all this phase noise chat. It’s one of the key factors that determines the overall success or failure of your radar or communications application. It’s even more important in intense environments where strong vibration or g-force is a concern.

Why is maintaining low phase noise such a concern in these applications and environments? And how can you solve the problems associated with the effects of phase noise? By the end of this article, you'll know why and how you should decrease phase noise in your applications.

What's better than a crystal oscillator? A crystal oscillator combined with electronic frequency control (EFC)!

Of course, determining if EFC would be a good addition to your crystal oscillator circuit design (and if so, which method is best for you) comes down to your specific application and its requirements.

There are four options to choose from when selecting an electronic frequency control method for your crystal oscillator:

1. Pulse width modulation (PWM) & low-pass filter (LPF)
2. Reference RF signal & phase locked loop (PLL)
3. Voltage divide
4. Digital-to-analog converter (DAC)

In this post,  we'll take a closer look at each option and their best applications.