--------
Pluess, Tobias writes:

> In my very first GPSDO I built, I used a STM32F303. This one had a quite
> bad PLL stability, the frequency was varying over time in a sawtooth like
> manner for some reason.

It's called "spread-spectrum" and is done deliberately to game the EMI
criteria for various certifications.

By sweeping the frequency through a range, the peak energy of any one
frequency, as averaged over a second, drops correspondingly.

In many cases you can actually disable it, but you may have to punk the
manufacturer quite hard to find out what bit to set or clear.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
[email protected]         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.
_______________________________________________
time-nuts mailing list -- [email protected] -- To unsubscribe send an 
email to [email protected]
To unsubscribe, go to and follow the instructions there.

Reply via email to