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Binyamin
Level II

Spectral Density Reports and Modifications from Time Series Analysis

Hi All,

 

I've been using this feature since JMP 16, it's a real big saver in trying to churn out multiple magnitude vs. frequency graphs.  I'm trying to sort out issues in my data, and was hoping for some scripting help, and request for features.

 

1) When I save my spectral data the period and frequency columns do not consider the time scale I used to make the time series graphs.  So I am repeatedly making a new column that is Frequency/delta_time.  (I verified this is valid by playing my bass guitar through my scope playing the A string.)

 

2) The Spectral Density Magnitudes seem orders of magnitude lower than my input data.  From my understanding Spectral Density units should be the same as my input on JMP, whereas Spectral Density of Volts would be Volts^2/Hz?

3) Since I'm using this for vibration analysis what scripting would need to be done to also automatically convert my measured voltage into three columns of acceleration, velocity and displacement?

4) The nice feature in JMP 18 is that they all get automatically get saved into one big file, unfortunately it's not super clear as to which file is which, because it seems to lose part of the original file name in the combined file when making the Group in Save column.

 

Cheers and Many Thanks,

 

Ben

2 REPLIES 2
michaelh
Level II

Re: Spectral Density Reports and Modifications from Time Series Analysis

No answers, but just to point out in previous vs of JMP, the "by" variables from the time series analysis would be in the spectral density table. Now there is just the "Group in Save Spectral Density" column with a generic "Periodogram for [variable]" sequentially numbered. I have hundreds of separate time series now with no identifying labels in the spectal density table. 

Binyamin
Level II

Re: Spectral Density Reports and Modifications from Time Series Analysis

That feature has been a bit of a life saver when batch converting around 30 files together.  It's a bit annoying having to then make another summary table and match up the "Group in Save Spectral Density" with the file information. I used to have to concatenate all of the files while my screen filled up with a mess of windows.

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