replicating FB architecture?

Hal Murray hmurray at
Mon Mar 30 04:57:42 UTC 2020

> Has anyone tried to create a low-cost stratum 1? Is the minimum cost a
> chip-scale atomic clock? 

It depends on what you mean by "stratum 1".

If you have an atomic clock, you still need some mechanism to get it started.  
If you just plug it in, it will (after warmup) give you good frequency.  The 
time output will be the equivalent of  your microwave blinking 12:00.  You 
need some external source of time to "set" it, the equivalent of setting an 
old pendulum clock to the correct time after you take it out of the box and 
wind it up.

The usual low cost source of good time is GPS.

In the context of NTP, stratum 1 means any source of time external to the 
(large) collection of NTP clocks.  In addition to time, it also has to supply 
some estimate of accuracy which may change over time.  So the minimum cost 
would be an NTP server setup to use it's local crystal.  It would provide good 
time for a short duration after you "set" it, but get less good over time.

These are my opinions.  I hate spam.

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