[time-nuts] Is this DOCXO an SC or AT cut rock?
Garry Thorp
GThorp at pascall.co.uk
Mon Aug 11 08:25:57 EDT 2014
Scott,
It doesn't look like AT-cut. AT-cut oven crystals are run at their upper turnover point, which is a minimum, so the frequency starts high from power up at normal room temperature.
With SC-cut, the f/T curve is shifted to the right and they are operated at their lower turnover point (a maximum), so the frequency starts off low.
Regards,
Garry
On 08/10/2014 08:54 AM, Scott Newell wrote:
I'm curious if an OCXO has an SC or AT cut crystal in it. There's no
EFC, so I can't measure sensitivity. I did measure the frequency
change from cold startup, thinking that an SC cut would stabilize
quicker than an AT. I don't have a good AT OCXO to compare against,
but I do have a Morion MV89A (should be an SC, right?).
Graphs:
http://n5tnl.com/time/mv89a/mv89a.png
http://n5tnl.com/time/mv89a/unknown.png
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