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FFT Y-Output Values don´t correspond expactions regarding Input

Hi

i am quite stuck with this problem and could really need help:

 

my Situation right now:

- concatenated 121 files with each 21000 measurments each, to a torque channel ( MyR ) and a rpm channel( Rotspd ) via skript

- created a numerik time channel ( time ) starting a 0-72600s, with 2541000 number values based on the number of files and measurements.

- choose FFT (One Time Signal), Time channel: time, Signal channel: MyR, Window type: Retancle, FFT: Amplitudepeak, Average Amplitude:    None, Third/Oktave: No

( PIC: 1-3 )

 

my Problem:

after applying the FFT, i displayed the results and :

-the original measurment values&peaks do not correspond to the resulting amplitude peaks

 

i am using:

DIAdem 2015

15.0. (64 Bit)

 

How do i achieve the output values regarding peaks in my FFT output ?

Is there a better signal analyse funktion in Diadem besides FFT which results in Frequency(X) and Amplitude(Y) ?

 

Kind regards and big thanks in advance

Knicks

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Message 1 of 4
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Try selecting the top blank entry from the time channel scroll down in the FFT function

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Message 2 of 4
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Hey gsklyr

 

 

When setting the top entry blank, the channel has be to in Waveform which, after converting from a numerik channel, doesn‘t seem to change the result. 

 

In your Project, a peak max value of Noise_3 is around 0.8 but after the FFT the resulting max value of Noise_3 is around 0.004.
So why is that, and how can i achieve a result with Frequency (X) and Amplitudepeak (Y) with fitting values ?

 

Appreciate your help in advance 

Knicks 

 

 

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Message 3 of 4
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Well the signal Noise_3 would be the sum of all the frequencies that make up this signal.  0.8 [Pa] seems to be a place where a lot of those frequencies intersect...  I don' think the output of the FFT function is bad

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Message 4 of 4
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