[time-nuts] Re: Power and heat re: Heathkit WWV clock / where are the good oscillators?

[Hal Murray]

Azelio Boriani said:
> The Swiss MicroCrystal claims +/- 1ppm accuracy and +/- 0.09 seconds per day
> for their RTC modules. <https://www.microcrystal.com/en/products/
> real-time-clock-rtc-modules/> 

Note that the slots in that table with 1ppm are for 25C.

I looked at the data sheet for the top slot: 2.5ppm over -40 to +85C.

There is a graph for the temperature of the crystal that goes to over 100 ppm 
so I assume there is some trickery to add/drop pulses.  That is probably OK if 
you are driving a watch but may be "interesting" in other applications.


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