[time-nuts] Is it Hz or MHz ?

Tom Van Baak tvb at LeapSecond.com
Mon Jun 2 04:51:26 EDT 2014


> The value of 5E^-11 refers to the resolution that the precision can be 
> relied upon after taking into account all the factors that influence 
> it.  It means that there is an error that can be as much as +/-5 parts 
> per e^-11.

No, it can be way more. A 5e-11 spec value is likely just RMS, or 1-sigma. Actual measurements will show significantly larger 2-sigma, 3-sigma, etc. value.

Your "as much as" wording sounds more like a 6-sigma, or peak-to-peak spec.

One must be very careful to match the measurement used to make the spec with how the device is intended to be used. For example, Magnus will likely tell us about MTIE, which is a perfect-storm, worst-case time error spec. It's very different from rough 1-sigma specs we usually talk about.

/tvb




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