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Inside Frequency Control

Bliley Technologies

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Ultimate Guide to Understanding Phase Noise

Posted by Bliley Technologies on Feb 20, 2020 9:00:00 AM


Maintaining strong frequency stability in electronic RF circuits by eliminating phase noise is important in many high-end communication applications. This is especially true for precise targeting in radar systems and spectral purity in other communication systems.

Let's take a deep dive into exactly what phase noise and jitter mean. This will help give you a better idea as to why reducing a system's phase noise is significant.

What Is Phase Noise?

Phase Noise  is represented in the frequency domain of a waveform and consists of rapid, short-term, random fluctuations in the phase (frequency). This is caused by time domain instabilities (jitter).
 
Be sure not to confuse phase noise with Jitter. Jitter is a method of describing the stability of an oscillator in the Time Domain. It combines all the noise sources together and shows their effect with respect to time.

In the simplest terms, phase noise describes the stability of an oscillator in the Frequency Domain, while jitter describes stability in the Time Domain.

A Simple 5-Step Path to Understanding Phase Noise

To build an in-depth understanding of phase noise, try using this simple 5 step process. Once you understand the 5 steps, you'll understand what makes phase noise...well... phase noise! 
 
 
"How does Spectral Density connected to Phase Noise in the 5 step process?" you ask? Here's some more details on each step.

Step 1: Spectral Density

Spectral Density is a measure of a signal's power intensity in the frequency domain.  The spectral density provides a useful way to characterize the amplitude versus frequency content of a random signal.

Step 2: When plotting each spectral density point at varied frequency intervals of your choosing (In this case every 1Hz), you're left with a graph that looks like this:

Step 2: Signal Power Density

You are now looking at what is known as the Signal Power Density of the noise. 

Now focus only on the upper sideband of the graph from fstart to fstop, this is called the "Single Side Band".

Step 3: Noise Power Density

We can now refer to the plotted part of the single side band as noise (Anything above the nominal oscillator frequency (Fosc) and not harmonically related can be considered phase noise). The technical term for this part of our graph is Noise Power Density (Step 3). We measure noise power density in dBW (LOG(Watts)) at this point because of the large range which we are looking. 

Step 4: SSB Noise Density

When we combine the single side band and Noise Power Density, we are actually measuring what's called SSB (Single Side Band) Noise Density

Step 5: Phase Noise

Finally, we can look at this in the time domain and we see a "jittery" waveform (see graph), we are looking at "jitter". Because the jitter is much smaller than one complete period (see graph), we can say it is caused by "Phase Fluctuations" (instead of frequency fluctuations). Since these fluctuations are noise, it's actually  phase noise.
 
So...
SSB Noise Density = Phase Noise
...and that's where phase noise comes from! Easy, right?

What Causes Phase Noise?

Phase noise in higher-end applications (such as radar communications, military communications, and space & satcom communications) is typically caused by
  • High vibrations
  • Micro vibrations
  • g forces and acceleration sensitivity
Using an anti-vibration, g-sensitivity crystal oscillator is the best way to eliminate phase noise from all of these potential sources.
 
Here are some common sources of phase noise in crystal oscillators.
 
Random Noise Sources:
Related: Causes and solutions for phase noise in high-end radar and communication systems.

What's Next? Learn How to Achieve Low Phase Noise...

Achieving low phase noise in a crystal oscillator is critical to achieving high-performance. Therefore, it's important to understand an in-depth look at phase noise. Instantly download our free visual guide to the impact of phase noise on various applications.
 
Now that you know all about phase noise and jitter, you might find it useful to learn about the  best output signal type in your oscillators.
Download our visual guide to the effects of phase noise
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Topics: engineering, crystal oscillators

10 Popular Software Defined Radios (SDRs) of 2020

Posted by Bliley Technologies on Feb 4, 2020 11:19:00 PM

Back in 2016, we wrote one of our most popular posts covering 12 popular Software Defined Radios or SDRs.  While the previous post still holds some extremely valuable information, a lot has changed in 3 years... especially the technology related to SDRs.  So we thought it was time for an update.

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Topics: RF Technology, general

5 Great Engineering Laptops (Plus Free CAD Tool Guide)

Posted by Bliley Technologies on Feb 4, 2020 11:17:00 PM

Finding the Best Performing Engineering Laptop

Our engineering team at Bliley is growing, which is great, but it also introduces some new challenges for small business like ours... finding the best performing engineering laptops for our engineers.

We want to give our engineers the best tools available and create an environment where they can be their most innovative and do the best work of their careers.  Of course, a key to this whole equation is the technology they use day-to-day to get those next generations products designed. We recently kicked off a search for the best laptops that are perfect for engineering workloads. As you can probably imagine, the ideal laptop for an engineer needs to have great compute and graphics power.

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Topics: engineering, General Topics, general, Engineering Equiptment

Top 18 CAD Tools for RF and Microwave Design Engineers

Posted by Bliley Technologies on Feb 4, 2020 4:17:00 PM

RF and Microwave Design can be ENJOYABLE...

Don't believe me? Many of us already know how designing can easily become extremely long, boring, and tedious. This is especially true for all you RF and Microwave Design Engineers!

Spending hours upon hours designing, finding problems, fixing problems, then repeating the process all over again...It all can become so mentally draining.

Am I bringing back bad memories? Sorry, time for the good news...

So how can you make the long and tedious design process easy (and possibly even enjoyable)? 

You guessed it... Automation and design tools are key. 

Having some great CAD tools on your side can release a significant burden off your back. These tools can save you time and dramatically increase your productivity. Our Top 4 Productivity and collaboration tools will help skyrocket your productivity even further.

Today, we thought we'd help you out by sharing these 18 CAD design tools that can lead to a more simple & enjoyable design session.

**Related Post: Check out our picks for the 5 best laptops for engineers.**

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Topics: engineering, General Topics, general

12 Engineering Thought Leaders You Should Follow On Twitter

Posted by Bliley Technologies on Feb 4, 2020 1:05:00 PM
 
Twitter has become a great way to keep track of current events, find out what's trending, and see what other people are talking about.  Engineers have been using Twitter since the very beginning to connect and share relevant content.  There are few recognized thought leaders that have amassed followers by the thousands.  They've got some epic engineering content that we think could help inspire, challenge, and inform even the most seasoned engineers.

Without further adu, here is our list of engineering thought leaders that you should be following on Twitter.

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Topics: engineering

5 Simple Steps for Truly Effective Design Reviews

Posted by Bliley Technologies on Feb 4, 2020 11:30:00 AM

As electronics and RF systems have become increasingly complex, the need to catch and fix errors during the design phase of a project has become increasingly important.

Catching an error during the design phase is orders of magnitude less expensive to fix than catching it during the manufacturing or test phases.

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Topics: engineering, general

Common Misconceptions About Crystal Oscillator Stability

Posted by Bliley Technologies on Feb 2, 2020 10:14:00 AM

RF engineers would love to get their hands on ideal crystal oscillator circuits. That is, a quartz crystal oscillator that transmits at the designated frequency for the entire life of the device without any frequency deviation. Unfortunately, that ideal circuit world is a mathematical fantasy.

There are many factors that contribute to quartz oscillator stability and frequency drift issues. To prevent these problems as much as possible, having a firm understanding of precise frequency stability will help give you the tools to keep your applications performing optimally. But there's another problem...

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Topics: crystal oscillators, RF Technology

[Press Release] Bliley Partners with ATM Mid-Atlantic in D.C, Maryland, and Virginia

Posted by Bliley Technologies on Sep 10, 2019 3:35:41 PM

ERIE, PA — TBD

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Topics: Press Release

[Press Release] Bliley Partners with Tritek Northwest in the Pacific Northwest

Posted by Bliley Technologies on Sep 10, 2019 9:08:41 AM

ERIE, PA — TBD

Bliley Technologies, leader in the design and manufacturing of Precision Oscillators and Timing Solutions for Communication, Industrial, Military, and Space applications, has announced their newest external sales representative partnerships.

Bliley is excited to add Tritek Northwest to their list of North American sales representatives.

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Topics: Press Release

How are Robots Used in Space Exploration?

Posted by Bliley Technologies on Sep 10, 2019 8:22:00 AM

Historically, the role of robotics in space exploration has been significant due to the uninhabitable conditions of non-terrestrial planets in the solar system. According to AZO Robotics, a robot is defined as “a self-controlled device consisting of electronic, electrical or mechanical units that can function in place of a living agent.” In this post, you'll learn some basic history about robots in space exploration and 5 of the most popular robotics systems used in space history.

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Topics: General Topics