I'm willing to bet a 50ppb oscillator will be a lot more accurate than most frequency counters, at least the affordable ones.
My untrimmed DS3232 is averaging 0.6PPM after 6 years. I'm just gonna let that thing run year-after-year without changing the time to see how accurate it is. And also because I forgot how to set the time (gotta dig thru my notes). I finally had to recharge the battery for the *first *time. On Thursday, April 22, 2021 at 9:28:59 PM UTC-7 Kevin A. wrote: > **Ovenized**, not 'oversized'... or are those the same? > > On Fri, Apr 23, 2021, 12:26 AM Kevin A. <[email protected]> > wrote: > >> On the subject of stable free running time bases, for an extra $10+ over >> the DS3232 (2 ppm) you could use a DOT050V-010.0M VCTCXO as a clock source >> to get 50 ppb stability. Just trim out the voltage control (with an 18+ bit >> dac) to be bang on 10 MHz against a good counter. >> >> It is a temperature compensated crystal, so "small" footprint compared to >> big oversized oscillators that get you into the single digit ppb for much >> more cost, size, power. Diminishing returns and all that... >> >> On Mon, Apr 19, 2021, 6:48 PM 'Grahame' via neonixie-l < >> [email protected]> wrote: >> >>> Hi >>> >>> Against NTP, I noticed no measurable drift over the years that the clock >>> ran for. It did have problems with the back up PSU which made the clock >>> unreliable if it was powered down for too long. I never compared with GPS. >>> The main comparison was against UK mains stability. In the short term there >>> was noticeable differences but UK mains frequency is manipulated so in the >>> long term it is dead on 50Hz so synchronous clocks stay accurate. >>> >>> The DS3232 is a fantastic chip and my choice also for clocks not linked >>> to NTP or GPS. >>> >>> Grahame >>> >>> >>> On 19/04/2021 21:05, gregebert wrote: >>> >>> Grahame - Have you been able to detect any drift/inaccuracy of the >>> Rubidium timebase ? I would imagine that even comparing to GPS it would >>> take months, and perhaps years, to notice any drift. >>> >>> I was really surprised to see that a DS3232 in one of my devices worked >>> out to be 6e-7 after 6 years. >>> >>> On Monday, April 19, 2021 at 11:53:52 AM UTC-7 Sgitheach wrote: >>> >>>> Chuck >>>> >>>> I'm happy to help you... >>>> >>>> Start here and come back to me with any questions you have. >>>> >>>> http://www.sgitheach.org.uk/atomic.html >>>> >>>> Grahame >>>> >>>> >>>> -- >>> You received this message because you are subscribed to the Google >>> Groups "neonixie-l" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web, visit >>> https://groups.google.com/d/msgid/neonixie-l/25697d78-b1ae-47a7-9de5-ba3ba3540e24n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/neonixie-l/25697d78-b1ae-47a7-9de5-ba3ba3540e24n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "neonixie-l" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web, visit >>> https://groups.google.com/d/msgid/neonixie-l/28c73729-c5c6-d89c-c300-43055a663d5b%40googlemail.com >>> >>> <https://groups.google.com/d/msgid/neonixie-l/28c73729-c5c6-d89c-c300-43055a663d5b%40googlemail.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/6e8d38f9-c9f4-4e54-ba27-f115a33ca491n%40googlegroups.com.
