WTB, OCXO 12MHz 0.1ppm or less

[Lightages]

I have been poking around the webs, and I can't find an OCXO 12MHz. I can find 12.8MHz, but no 12. Anyone have a lead?

[miguelvp]

Can a PLL with a 15 multiplier and divided by 16 make it a 12MHz?

Or are there side effects by using a PLL?

Edit: do you mind sharing what 12.8MHz OCXO did you find that is better than +-0.1ppm?
Might be pricey but I would like to know.

[Lightages]

I am looking fr a simpler solution if possible. I am also not sure about the short term stability or jitter of a PLL setup.

[miguelvp]

Never mind about the part lookup, found some Abracon Corporation ones with 30ppb and even with 10ppb. (12.8MHz that is)

[Lightages]

That would be great, if they were 12Mhz 

[miguelvp]

Well if you decide for PLLs here are the ratios to get 12MHz out of (their) standard frequencies:

Code: [Select]

   MHz    mul/div
 10.00     6/5
 12.80    15/16
 13.00    12/13
 16.384  375/512
 20.00     3/5
 26.00     6/13
 38.40     5/16
 38.88    25/81
 40.00     3/10
100.00     3/25


[Lightages]

Thank you for the calculations. 

[codeboy2k]

I always use Mathomatic for pll fractional ratios

[Macbeth]

George Gesslein II? I've often wondered what all those 1%'ers do with their spare time. Besides secret TPP deals with world governments, ordering assassination of free energy pioneers, and other Bilderberg and Zionist stuff.

Actually that looks really lightweight and neat. Installing Mathomatic now... 

sudo apt-get install mathomatic

Gotta love how simple Linux is to do stuff!

[Lightages]

sudo apt-get install mathomatic

Gotta love how simple Linux is to do stuff!

And hard hard it is to do many other things. (No I do not want to start an OS wars here please)

[codeboy2k]

George Gesslein II? I've often wondered what all those 1%'ers do with their spare time. Besides secret TPP deals with world governments, ordering assassination of free energy pioneers, and other Bilderberg and Zionist stuff.

Actually that looks really lightweight and neat. Installing Mathomatic now... 

sudo apt-get install mathomatic

Gotta love how simple Linux is to do stuff!

Take a look here too:

https://www.eevblog.com/forum/beginners/adjustable-resistive-divider-resolution-improvement/msg612346/#msg612346

I show how I used mathomatic to quickly solve a system of 2 equations and 2 unknowns for a creating a voltage divider with a 5k trimmer in the middle, and requiring  V_min=4.0, V_max=4.5

You can input the 2 equations, re-arrange one to pull out a variable, substitute that back into the first equation, compute an answer, and then solve the 2nd unknown using the answer just computed.

[jpb]

I find that unusual frequency OCXOs are often available on ebay as they were more popular in the past - I got a 9.9MHz one this way.

Here is a 12MHz one:
http://www.ebay.co.uk/itm/OCXO-Double-Oven-Ultra-Precision-For-CORNING-OCO1000-12-12-0MHz-/221656205292?pt=LH_DefaultDomain_3&hash=item339bbd47ec

I've no idea if they are any good but at the price it is probably worth experimenting.

[miguelvp]

I find that unusual frequency OCXOs are often available on ebay as they were more popular in the past - I got a 9.9MHz one this way.

Here is a 12MHz one:
http://www.ebay.co.uk/itm/OCXO-Double-Oven-Ultra-Precision-For-CORNING-OCO1000-12-12-0MHz-/221656205292?pt=LH_DefaultDomain_3&hash=item339bbd47ec

I've no idea if they are any good but at the price it is probably worth experimenting.

There are many 12MHz ones, the problem is that the ones you can find are only 50ppm and the OP wants 3 orders of magnitude better than that.

[jpb]

I find that unusual frequency OCXOs are often available on ebay as they were more popular in the past - I got a 9.9MHz one this way.

Here is a 12MHz one:
http://www.ebay.co.uk/itm/OCXO-Double-Oven-Ultra-Precision-For-CORNING-OCO1000-12-12-0MHz-/221656205292?pt=LH_DefaultDomain_3&hash=item339bbd47ec

I've no idea if they are any good but at the price it is probably worth experimenting.

There are many 12MHz ones, the problem is that the ones you can find are only 50ppm and the OP wants 3 orders of magnitude better than that.

I don't have the datasheet for the Corning OCO1000-12 that I linked but they claim to be double oven OCXOs so I would expect them to be parts per billion not parts per million.
50ppm sounds more like a TCXO.

Having said that, ones retrieved from old equipment (such as these ebay ones) will probably be out of spec anyway.


After a bit of web searching I found the data sheet. They are AT cut but they are 100 ppb so should be in the right ballpark.

[miguelvp]

They do get better with time just like a good wine

[Lightages]

Thanks for the tip on the uk ebay, but it doesn't look like they will ship to Chile. Also I could not find a data sheet for the part so it is not worth risking the money. Usually parts marked with "12000" are going to be low accuracy parts. To get something better they usually have more zeros in the part number

[jpb]

They do get better with time just like a good wine

If they are treated nicely. If they were removed from the board with pliers and a blowtorch they might not be in such wonderful condition!

OCXOs off ebay are very much pot luck. I've bought about 10 for my collection but at least four of them were duff though I got replacements or my money back. Even the others might not be in spec, they are the right frequency but I've not had the time or until recently the equipment to test them properly. (I'm very slowly designing and building a GPSDO for fun and educational purposes.)

[jpb]

Thanks for the tip on the uk ebay, but it doesn't look like they will ship to Chile. Also I could not find a data sheet for the part so it is not worth risking the money. Usually parts marked with "12000" are going to be low accuracy parts. To get something better they usually have more zeros in the part number

I think that this is the datasheet :

http://www.ic72.com/pdf_file/o/93101.pdf

I guess that they are on international ebay - it is just that I'm in the UK so search uk ebay.

[iMo]

I think that this is the datasheet :
http://www.ic72.com/pdf_file/o/93101.pdf

I've ordered the above Corning OCO1000 12MHz for my older counter.
Any practical measurement with the Vs current (@5V) required for warm-up and operation?
Thanks