[time-nuts] Re: The STM32 GPSDO, a short presentation

[Carsten Andrich]

Hello Erik,

could you elaborate on your setup? Which oscillator (OCXO?) are you 
using to drive the STM32's PLL?

I'm currently toying around with a (presumarly?) similar configuration. 
An RCB-F9T's 1PPS fed into an STM32G4's 32-bit timer capture to 
reference the 1PPS to a local oscillator with ~6 ns resolution, 
subsequently generating a stabilized 1PPS using another output channel 
of the same timer. The STM32's PLL is still using a cheap chrystal, but 
I'm currently working on replacing that with an OCXO.

Best regards,
Carsten

On 01.04.22 18:19, erik at kaashoek.com (Erik Kaashoek) wrote:
> Nice, I'm trying to do something similar. But without the PICdiv or the
> TIC measurement. Only the GPS PPS into the STM32 and the stabilized PPS
> is generated by a timer in the STM32
> First step was to measure against the running average of the GPS PPS.
> As can be seen in attached Timeplot measurement the phase error is (when
> temperatures stabilized) in the order of 10ns.
> Erik.