Electronics World Cover,TOC,and list of posted Popular Electronics articles QST Radio & TV News Radio-Craft Radio-Electronics Short Wave Craft Wireless World About RF Cafe RF Cafe Homepage RF Cafe in Morse Code Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs Twitter LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes AN/MPN-14 Radar 5CCG Notable Quotes App Notes Calculators Education Magazines Software,T-Shirts,Coffee Mugs Articles - submitted by RF Cafe visitors Simulators Technical Writings RF Cafe Archives Test Notes Wireless System Designer RF Stencils for Visio Shapes for Word Search RF Cafe Sitemap Advertising Facebook RF Cafe Forums Thank you for visiting RF Cafe!

Crystal Reference Oscillator Design - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Original posts:

Amateur Radio | Antennas | Circuits & Components | Systems | Test & Measurement

Post subject: Crystal Reference Oscillator Design. Posted: Sun Oct 21, 2007 3:25 am


Joined: Tue Feb 27, 2007 6:16 am
Posts: 46

For the sake of learning and my own interest, I have been designing a UHF data radio.

Is this correct ?
If my carrier freq is 450.325MHz accurate to +/-200Hz
Lets say Im using a 20MHz Crystal reference oscillator for my PLL.
Then a rough calculation tells me that my crystal must be accurate to within -> 20*PPM*(450.325*10^6)/(20*10^6) < 200 -> 0.44PPM.
Where PPM is parts per million.

If these calculations are correct, can anyone recommend where I can find a crystal reference ocillator with a TTL or CMOS output, accurate to 0.44PPM? I believe an oscillator from 5MHz to 25MHz would be suitable.

FYI my channel width is 25kHz, Im using National's LMx2346. Thankyou

Regards Darcy Randall, Perth, Western Australia

Regards, Darcy Randall, Perth, Western Australia


Post subject: Posted: Sun Oct 21, 2007 5:14 am

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hello Darcy,

Your calculation is correct.

For such a tough spec as you have a simple Crystal is not good enough.
You should use a TCXO. I found an example for one with 0.28PPM and a CMOS output:

http://www.valpeyfisher.com/openlink.as ... FTX160.pdf

You can also ask for samples and define the frequeny that you need. Please contact the manufacturer for further help.


Post subject: Posted: Sun Oct 21, 2007 9:03 pm


Joined: Tue Feb 27, 2007 6:16 am
Posts: 46
Legend. Thankyou

Regards, Darcy Randall, Perth, Western Australia

Posted  11/12/2012

RF Cafe Software

   Wireless System Designer - RF Cafe
Wireless System Designer

RF & EE Symbols Word
RF Stencils for Visio
Calculator Workbook
RF Workbench
Smith Chartâ„¢ for Visio
Smith Chartâ„¢ for Excel

About RF Cafe

Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2022
Kirt Blattenberger,

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:

Try Using SEARCH
to Find What You Need. 
There are 1,000s of Pages Indexed on RF Cafe !