Hi Bob,
If one prototypes any crystal oscillator, and runs it on a bench. Then
builds an 'oven' of sorts and runs it on the same bench. Would you
expect to see any improvement?
In other words for a given oscillator (crystal and electronics, etc),
will there be any improvements in an oven compared to not in an oven?
Or, are there other things that outweigh the gains by temp controlling
the whole thing.
Yeah, this is a pretty open question, but I don't really have a feel for
how good an oscillator needs to be before an oven starts to improve
things...
Dan
On 3/15/2017 12:00 PM, time-nuts-requ...@febo.com wrote:
Hi
Where do you plan on getting an OCXO grade crystal at an odd frequency like
that? Much of the performance of a good OCXO is in the crystal. Doing a proper
design on one is a lot of work. You *might* think that having a design for
5.000000
MHz would give you a good design for 5.000050 MHz. I have empirical evidence
that
this isn’t the case. Many years later, I’m still utterly amazed that this is
the way things
work in the crystal business ….( = it’s not just a design issue, it’s also a
business decision)
More or less the crystal needs to be:
1) Cut specifically to have a turn at a temperature that makes sense for your
application.
2) A “large blank” design (for it’s frequency)
3) In a cold weld package (most of the normal crystals are resistance weld)
4) Run through a high vacuum / high temperature process
5) Be plated with gold rather than something like silver or aluminum (unless
it’s at VHF).
6) Have a motional capacitance that makes sense for your EFC range ( normally =
minimize)
7) Preferably be an SC or modified SC cut.
This is for a high stability part. The list does keep going on for a while, but
that should
give you a pretty good idea.
Bob
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