[time-nuts] Re: Time stamping of data

[Bob Camp]

Hi

The quick and simple version:

Fire up a clock. Off it goes. Does it do decimal seconds or something else?
That’s up to you and is application dependent. Does it roll over at some point or
does it count on to infinity? Again, application dependent. 

You likely start it with some starting value. It could be zero, it also could link to 
something like UTC. That link (or lack there of) is very application dependent. 

In comes a zero crossing.

Grab the time value from the clock. (possibly to nanoseconds, picoseconds or 
some other level of resolution / accuracy),

Stuff that value in a file (or maybe display it, though that’s less common).

Step and repeat for each zero crossing. 

Why do this?

1) It’s a zero dead time way to look at things. A “delta time between crossings” 
approach might take a while to get ready for the next zero crossing.

2) It takes out potential cumulative errors (compared to delta time). If each delta time
short by 1 ns, you are off by 10 ns after ten readings. Yes, that would be a really poor
delta time measure. 

3) You might want to know when an event happened “as received” at various 
locations. That would get you into time sync at possibly a pretty crazy level of
accuracy. 

Is that everything? This is Time Nuts …. it’s never “everything” :) :).

Bob



> On Aug 23, 2024, at 5:39 AM, Dana Whitlow via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Hello,
> 
> I keep reading references to time stamping, but
> am only vaguely aware of what this does and how
> it is done.
> 
> Is there a sort of "primer" on the subject?
> 
> Thanks,
> 
> Dana Whitlow
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