The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
May 4th, 2024, 4:23am
Pages: 1
Send Topic Print
Relationship between PPM & Jitter (Read 12105 times)
gavin
New Member
*
Offline



Posts: 7
Canada
Relationship between PPM & Jitter
Jun 29th, 2010, 6:58am
 
I've been searching on the internet for a while but cannot find a good article outlining the difference/relationship between jitter and PPM.

Can anyone explain to me the difference/relationship between jitter & PPM?

In what application would PPM be of most concern? In what application is jitter of most concern?

Thanks,
Gavin
Back to top
 
 
View Profile   IP Logged
Ken Kundert
Global Moderator
*****
Offline



Posts: 2384
Silicon Valley
Re: Relationship between PPM & Jitter
Reply #1 - Jun 30th, 2010, 12:04am
 
PPM?
Back to top
 
 
View Profile WWW   IP Logged
Mayank
Community Fellow
*****
Offline



Posts: 334

Re: Relationship between PPM & Jitter
Reply #2 - Jun 30th, 2010, 1:30am
 

Parts Per Million (PPM) is a unit for relative measurement.

1e6 parts per million = 100%.
100 parts per million = 0.01%.

OR

1% = 10,000 PPM

Hence a  rms jitter of 1% of the Time Period is equivalent to 10,000 PPM.

--
Mayank.
Back to top
 
 
View Profile   IP Logged
gavin
New Member
*
Offline



Posts: 7
Canada
Re: Relationship between PPM & Jitter
Reply #3 - Jun 30th, 2010, 8:06am
 
I guess I should be clearer, what I'm looking for is the relationship between Oscillator Tolerance (typically specified in PPM) and Jitter.
Back to top
 
 
View Profile   IP Logged
gavin
New Member
*
Offline



Posts: 7
Canada
Re: Relationship between PPM & Jitter
Reply #4 - Jun 30th, 2010, 8:38am
 
I've been doing some more research and here's what I found.

When dealing with Jitter and Tolerance I'm looking at oscillator stability.

Stability can be broken down into 3 categories:
1/ Long Term Stability eg) greater than 1 day
2/ Short Term Stability eg) 1s to 1 day
3/ Very Short Term Stability (or Phase Noise) eg) less than 1s

Tolerance would fall into categories 1 & 2 whereas Jitter would fall into category 3.

So basically they I am measuring different specs of an oscillator when I measure Jitter and when I measure tolerance.

Any thoughts?

-Gavin
Back to top
 
 
View Profile   IP Logged
Ken Kundert
Global Moderator
*****
Offline



Posts: 2384
Silicon Valley
Re: Relationship between PPM & Jitter
Reply #5 - Jun 30th, 2010, 9:20am
 
I am not familiar with Oscillator Tolerance. Tolerance to what?

I am also not seeing a clearly defined question. Perhaps you can further clarify what you are looking for.

-Ken
Back to top
 
 
View Profile WWW   IP Logged
gavin
New Member
*
Offline



Posts: 7
Canada
Re: Relationship between PPM & Jitter
Reply #6 - Jun 30th, 2010, 9:53am
 
Ken Kundert wrote on Jun 30th, 2010, 9:20am:
I am not familiar with Oscillator Tolerance. Tolerance to what?


Crystal oscillators typically specify a nominal frequency as well as a "tolerance" about that nominal frequency since no oscillator can output a single frequency perfectly. For example, if I want to buy a 25MHz oscillator I will find the manufacturer might have 25MHz +/- 50PPM while another might have +/- 1PPM (at a higher cost of course). The 50PPM and 1PPM is what is called the tolerance of the oscillator.

Ken Kundert wrote on Jun 30th, 2010, 9:20am:
I am also not seeing a clearly defined question. Perhaps you can further clarify what you are looking for.


What I was trying to understand was the relationship (if any) between the Jitter specification (typically provided in ps rms in the digital world) of an oscillator and the Tolerance specification (typically measured in PPM or parts per million).

My second post was some things I found searching on the internet which somewhat answered my question - they are measuring two different things. But, not being an expert I was looking to see others thought.  

-Gavin
Back to top
 
 
View Profile   IP Logged
hyy95
Junior Member
**
Offline



Posts: 10

Re: Relationship between PPM & Jitter
Reply #7 - Jun 30th, 2010, 3:25pm
 
Tolerance is the character of the crystal, it tells you how precise the manufacture cut the crystal, it's like process variation.

Jitter is the attribute of the oscillator circuit, it relates to phase noise.

That's my understanding, i maybe wrong.
Back to top
 
 
View Profile   IP Logged
love_analog
Senior Member
****
Offline



Posts: 101

Re: Relationship between PPM & Jitter
Reply #8 - Jul 29th, 2010, 7:31am
 
Gavin
There is no correlation between ppm and jitter. The former is more of a dc quantity (if you may), the latter is more of phase noise at a given point of time.
Back to top
 
 

loveanalog.blogspot.com
The Power of Analog
View Profile   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2024 Designer’s Guide Consulting, Inc. Designer’s Guide® is a registered trademark of Designer’s Guide Consulting, Inc. All rights reserved. Send comments or questions to editor@designers-guide.org. Consider submitting a paper or model.