[hpsdr] crystal Oscillators

[Eric Ellison]

Hi Chuck/All

Oscillator Manufacturers - The myriad! Has everyone looked at all of these
for the best for Gibralter? I think not. But if someone can define the major
parameters we are looking for I for one can 'google with the best of em!". I
think others might also join that search and 'divide and conquer'. These
jewels ain't cheap, so how do we know which is 'best' to try. Is there a
Consumer Reports comparison? (smile)

http://www.interfacebus.com/oscillators.html


Last year when we started discussing Gibralter someone mentioned MCXO,
which, since we are Software/Firmware Defined sounded GREAT to me. The
discussion drifted off to other things, and I stopped my search. Would an
MCXO be suitable? Not discussed were DCXO (Digitally Compensated) and DCTXO.
A quick Google shows that this arena is expanding. Are computer generated
noise levels too high. Cost?

Some MCXO Links pulled at random.

http://www.cedcc.psu.edu/proj/mcxo/


Microprocessor Compensated Crystal Oscillator

http://www.pmdinc.com/mcxo.html


How it does Temperature Compensation

http://www.ieee-uffc.org/freqcontrol/quartz/vig/vigcateg.htm


Comparison of Oscillator types benefits/liabilities:

http://www.electronicproducts.com/ShowPage.asp?FileName=crystek.mar2005.html

Many Many more papers and links for MCXO!

Thanks
Eric


-----Original Message-----
From: hpsdr-bounces at hpsdr.org [mailto:hpsdr-bounces at hpsdr.org] On Behalf Of
Chuck Hutton
Sent: Friday, June 15, 2007 11:04 PM
To: hpsdr at hpsdr.org
Subject: Re: [hpsdr] crystal Oscillators

***** High Performance Software Defined Radio Discussion List *****

While that's true for some odd cuts of crystals, the popular AT cut (when
outside its flat area) increases in frequency with increases in temp and
decreases in frequency with decreases in temp. 

Take a look at the bottom chart on this page:
http://www.citizen.co.jp/english/crystal/aspect/index.html


Chuck

Date: Thu, 14 Jun 2007 17:26:24 -0700 (PDT)
From: FRANCIS CARCIA <carcia at sbcglobal.net>
Subject: [hpsdr] crystal Oscillators
To: hpsdr at hpsdr.org
Message-ID: <685290.32796.qm at web82312.mail.mud.yahoo.com>
Content-Type: text/plain; charset="iso-8859-1"

Most crystals flip over at about 30 degrees C meaning above and below that
temperature the frequency will go down. Heating or cooling has the same
effect on either side of the slope. 
  I prefer the option to use my own VCXO having a few. This would allow the
user to upgrade if desired. 
  My USB2 card is in the mail and breadboard almost built so hope to power
up some time next week and join in the fun. I'm mounting a couple linear
power supplies and Atlas on a plate until I decide how I want the final
package. Frank WA1GFZ

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