Windfreak Technologies
LadyBug Technologies LB5944A RF Power Sensor - RF Cafe
 

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024
Webmaster:
    Kirt Blattenberger,

    BSEE - KB3UON

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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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:

AirplanesAndRockets.com

Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes App Notes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Homepage Thank you for visiting RF Cafe!
Anatech Electronics

Synchronizing two crystal oscillators - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. If the folks at phpBB would release a version with integrated sign-in from the major social media platforms, I would resurrect the RF Cafe Forums, but until then it is probably not worth the effort. Regardless, there are still lots of great posts in the archive that ware worth looking at.

Below are the old forum threads, including responses to the original posts.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

eran
Post subject: Synchronizing two crystal oscillators Posted: Sat Nov 24, 2007 3:26 am

Lieutenant


Joined: Fri Nov 23, 2007 11:59 am
Posts: 4
Location: Israel
Hi Guys,
I have xo for my VSAT tuner, and I'm currently designing the LO for my burst receiver (direct conversion).
Problem: I have to use the tuner crystal oscillator, (synchronous LO's) but the main xo is located "miles" away from my LO, and it passes through LVDS.
The phase noise performance is awful: (-105dBc/Hz @1KHz) and I must use a local reference oscillator!!!(I need -35dBc integrated noise, with settling time of roughly 100us. I use a broad band VCO so it includes an active loop filter)
I was thinking to use a close by VCXO, and synchronize it with the main xo.
Question: What is the simple, cost effective way to implement such a synchronization loop (pll, costas)?
Your help will be highly appreciated,
Regards,
Eran.


Top

Feng
Post subject: Posted: Sun Nov 25, 2007 3:07 am

Captain


Joined: Sun Mar 19, 2006 5:25 pm
Posts: 21
Location: Burnaby
Hi Eran,

You may think about using GPS modules to synchronize them. A general GPS module can provide quite precise clock signal. Working with a VCXO, both the short term stability and long term stability can be achieved at the same time.

Hope it is little helpful.


Top

eran
Post subject: GPS module is overkillPosted: Mon Nov 26, 2007 3:31 am

Lieutenant


Joined: Fri Nov 23, 2007 11:59 am
Posts: 4
Location: Israel
I was thinking using a phase detector and vcxo at the same xo refference frequebcy(no prescaler is needed) and simply close a loop on the vcxo.
I only need to check the influance of the delay time, but as for the phase lock i think it will work.don't you think?


Top

eran
Post subject: Has anyone done it before?Posted: Sun Dec 02, 2007 3:32 am

Lieutenant


Joined: Fri Nov 23, 2007 11:59 am
Posts: 4
Location: Israel
did anyone implemented a sync. of two oscillators,and have comments?


Top

nubbage
Post subject: Posted: Mon Dec 03, 2007 8:04 am

General


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
Hi Eran
This is a comment requirement for the design of SONET/SDH multiplexers, where the synch clock is extracted from the data stream. If that should become corrupted or the link broken, the mux is required to free-run on its own internal TCXO, then re-synch when the stream is re-established. For that function the TXCO is continuously synched to the stream if it is there.
I have not seen the circuits that achieve this, but I guess there must be refs on the web to how it is done. Try a search engine with some key words like SONET, SDH and "clock".




Posted  11/12/2012
Copper Mountain Technologies - RF Cafe
Werbel Microwave - RF Cafe
 

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free