HP48 Clock error data results

[Dave Shaffer]

(03-03-2021 05:59 PM)TomC Wrote:  Very interesting - 40 seconds per year error is on the order of 1ppm! Quite impressive.

I'd note - maybe for your HP calculator, but nowhere near what a crystal oscillator can really do. These are microseconds per year stability! (1 year is ~3e7 seconds)

Check out these refs for parts in the 1e-12 to 1e-14 for a crystal oscillator. We used to use a Sulzer crystal system to clean up the output from our HP Rubidium standards (HP 5065A) for short-term (10-100 seconds) stability.

https://www.hpl.hp.com/techreports/1999/...%20circuit.

http://www.leapsecond.com/museum/sul25-1/

https://ieee-uffc.org/about-us/history/u...lications/