[time-nuts] Frequency Stability of Trimble Mini-T

[Hal Murray]

> We have done some extensive research trying to correlate jumps to
> external phenomena (radiation, vibration, thermal effects, etc).
> There is no straight forward correlation.

> It's similar to asynchronous switching inside a digital computer.
> You can add levels of flip flops to synchronize across two
> asynchronous time-domains,  ...

I think that's misleading in two ways.

First, we understand metastability.  We can measure it and predict it.  It it 
mattered, we could test each individual part.

Second, the failure mode is exponential in a parameter we can control.  So 
given a particular set of parts to pick from, it's reasonable to make a 
design with a probability of error small enough so that other things are much 
more important.


> If it absolutely, positively can't take any hit, then some more work is involved

I would say that the first step is to put a number on "absolutely, 
positively".

If you aren't willing to take some risk, you won't get off the drawing board.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.