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Average and/or standard deviation of PSDs?

I have a vibration standard that requires an average and the average + one standard deviation of my Power Spectral Density (PSD) functions.

 

In LMS Test.Lab, how do I calculate an average + one standard deviation on a group of PSD functions?

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Accepted by topic author TLUser23
‎10-30-2016 08:05 PM

Re: Average and/or standard deviation of PSDs?

Hi,

 

You can use the LMS Test.Lab Data Calculator function in LMS Test.Lab Navigator worksheet.

 

Put the PSDs functions in the Input Basket by right clicking on data and choosing “Add to input basket”.

 

inputbasket.png

 

Click on “Data Calculator” and press the “Add from Input Basket” button in the data set area.

 

datacalc.png

 

 

In the Active Formula Set area, add a formula “AVERAGE” (click on the "f(x)" button to get formulas)

 

 

 

AverageFunction.png

 

In the “Edit Formula arguments”, enter the following:

 

EditFormulas.png

 

F1, F2 and F3 refer to the PSD functions in the Dataset area.  It may be necessary to pick “New Function” button to enter all three.

 

Use the AVERAGE function twice:

  • The output should be set to “1” to get the average
  • The output should be set to “2” to get the average plus the standard deviation.

Also set the Point id for the resulting calculation by filling in the Point Id field:

 

 

Calculate.png

 

Press the “Calculate” button.  ‘Average’ will be at F4 and ‘Ave+StdDev’ will be at F5.

 

Click the “Save Results As” button to store results to the current project.