[time-nuts] Sneaky Errors

WarrenS warrensjmail-one at yahoo.com
Thu Oct 20 01:19:15 UTC 2011

Maybe  this is too simple

LadyHeather is always checking the Tbolt's "Internal Osc" value against the 
By watching it's plot outputs you can tell if the Tbolt is on freq. 
(compared to the GPS)
If no plot outputs, then something is broken, at that point is does not 
matter what, can assume it is that Tbolt.

A couple of other things to assume also for this to be the solution to the 

1)The GPS is Always right and is correct, IF one of the Tbolts fails IN any 
The GPS is used as the 3rd Osc to vote who is wrong when there is 
disagreement between the two Tbolts.

2) The Tbolt always has an output that is at the same freq as it's internal 

While not a critical fail safe for everything, this does cover the case 
If the two Tbolt do not agree, what one is wrong.  Answer is the one that is 
different than the GPS
When they are both close to the same freq (with-in 1e-9), don't need the 
GPS's vote, if you assume they are both right.


As long as the Thunderbolt is working perfectly it's built in error
checking will work fine.  This should be obvious as anything that
works, works.

But I can think of plenty for failure modes where the  built in error
checking might not work.  First off there could be a software or
firmware bug or a stuck bit in a ROM.   An open conecton on a DAC,
lots of things.   The assumption has to be the "broken hardware is
totally unpredictable"   We can not know in advance what it will do
after it breaks.

I'm not saying the built-in diagnostics are useless, just that they
are never 100% reliable

On Wed, Oct 19, 2011 at 2:18 PM, ws at Yahoo <warrensjmail-one at yahoo.com> 
> Simple way is to use LadyHeather.
> From its output, you can tell if either or both are working correctly as
> well as how well they are working.
> That is assuming of course that there is at least one working GPS 
> satellite
> in view at all times.
> If not it well tell you that also.
Chris Albertson
Redondo Beach, California 

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