[time-nuts] crystal (or MEMS) oscillators with low hysteresis

[Bob Camp]

Hi

The crystals in the TCXO's are about as well mounted for hysteresis as you
can practically do for the money. A typical clock oscillator guy does not
worry much about that sort of mounting. 

Sorting is going to be a good idea. There are a number of things you likely
will want to weed out. I'd plan on looking at a couple of different
frequencies as well as vendors. Some quality time with a slow ramp / high
data rate test setup should tell you a lot. 100 readings a degree and sub 1
degree per minute is the typical way to do it. Getting your temperature
probe so it doesn't lag can be a hassle even at 1C/ minute

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Jim Lux
Sent: Friday, September 07, 2012 4:10 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] crystal (or MEMS) oscillators with low hysteresis

On 9/7/12 12:20 PM, Bob Camp wrote:
> Hi
>
> I'm guessing that power is also an issue, so cheap OCXO's are out. If
that's
> true, I believe you are already at the "cheap vs good" inflection point
with
> the cell phone TCXO. At < $2 they are pretty tough to beat. Just the fancy
> crystal in something better is going to give you a big boost in the price.
>

power and size..

Yes.. the cellphone tcxo is probably it.. but I was wondering if 
something else that's not "TC" might not have better hysteresis 
properties.  Short of buying a batch and trying them... which I'll do, 
but before just randomly picking things out of the Digikey catalog, it's 
possible someone has more insight into the inner workings of cheap clock 
oscillators.

For instance, they make inexpensive fairly high performance low power 
oscillators for COSPAS (emergency locator beacon) and wildlife tracker 
use. But you'd never know that they have the higher performance unless 
you asked.



AT the high, expensive end, I've got all the data I need..



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