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by tverbeure 1071 days ago
I'm not sure: I remember seeing comments in the past about crappy Vref outputs of OCXOs (when compared to external Vrefs) and just today, I saw another such comment though I don't remember where either.

I've studied quite a bit of GPSDO schematics, but none of them are using the internal Vref. Though that maybe because these designs allow for different OCXOs, some of which don't have a Vref output.
1 comments
gsmecher 1071 days ago
Interesting. If you ever do track down the scuttlebutt on poor-performance internal regulators, please pass it along? I'm not terribly hard to find.
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tverbeure 1065 days ago
Here's the blog post that shows the bad quality of a (pretty expensive) Oscilloquartz 8663 OCXO: https://www.paulvdiyblogs.net/2023/07/building-10mhz-master-...

"Lastly, I'm not going to use the Oscilloquartz reference voltage to power the frequency setting circuit. It seems the logical thing to do, but this so called reference voltage is anything but a reference voltage. They are typically created by using a zener (reference) diode like the TL431, but that is simply not good enough as you will see."

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