STM32 Kit with high accuracy crystal

[IAhma.1]

Hi,

I am looking for an STM based MCU/kit with high accuracy crystal oscillator with possible option to fine tune the frequency. I want to use it for some high accuracy time reference. Looking for suggestion please.

- ijaz

[TDK]

0.003 s / 24 hour = 3.5e-8 = 0.035 ppm. This level of accuracy is not achievable with a crystal, or even a TXCO.

[Tesla DeLorean]

Ok, as TDK indicates that's 35 ppb

Can you use GPS/GNSS here as a reference source?

For elapsed time, you could get the receiver to time stamp events. (perhaps 15-20ns resolution)

Something like the NEO-M9N could generate a TIMEPULSE to frequencies into the 10's of MHz which while having some phase-noise/jitter in the near-term (64 MHz NCO) has very good long term clocking.

[IAhma.1]

Any other nearby solution other than GPS option? For removing that extra dependency on GPS signals!!!

What you think what will be the maximum drift in frequency (or in term of time /24hrz) of STM32-Discovery kit under controlled temperature of 22-28degree C?

[Uwe Bonnes]

Measuring in the sub-ppm range is demanding. Accurarcy has many aspects, absolute vs relative accuracy, long and short term stability and much more. You can get oven stabilized oszillators in the sub-ppm stability range, but absolute accuracy is alway above 1 ppm. If you need absolute accuracy, you need to discipline the clock with a reference clock like GPS. Or you buy a commercial clock source, but expect to pay 10 k$ and more.