[time-nuts] Framework for simulation of oscillators

Magnus Danielson magnus at rubidium.dyndns.org
Mon Mar 28 08:52:59 EDT 2016


Hi Tom,

On 03/28/2016 04:25 AM, Tom Van Baak wrote:
>> BTW: I discovered that Timelab stops processing after 10'000'000 datapoints,
>> which is kind inconvenient when doing a long term measurment...
>>
>> Attila Kinali
>
> I've collected a day of TimeLab/TimePod data at tau 0.001 which is 86'400'000 datapoints. Should be no problem.
>
> Note Stable32 has a user-configurable limit (Conf -> Data -> Max_Data_File_Size). Or you can decimate during reading.
>
> My command line tools have no sample limit (well, just malloc() limited) and can be orders of magnitude faster than Stable32 or Timelab since they are batch and not GUI.
>
> But this begs the question -- what are you doing with 10M datapoints? Once you get beyond a couple of decades of data it's often better to compute statistics in segments and display all the segments of the whole as a time series.
>
> So, for example, don't compute a single stddev or ADEV number from the entire 10M data set. While this gives an apparently "more precise" measurement due to sampling, it will also hide key factors like trends, periodicity, spectral components, outliers, and glitches.

Agree. You need to use a better tool for those systematics than ADEV is. 
MDEV and PDEV is even better at filtering out noise and give power 
estimates, which smoothes out it more, which thus just makes it harder 
to discover. The dynamic ADEV can help a litte.

It is the diversity of plots, ADEV, FFT and phase-/frequency-plots 
(residue plots of some suitable matching model) which can help to unveil 
behaviors of interest.

Swapping between MDEV and TDEV can at some times be illustrative.

Cheers,
Magnus


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