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yiersan123
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RMS/ magnitude and phase at fundamental frequency

Hi, does anyone know how to find the RMS or magnitude and the phase at fundamental frequency of a measured signal in Labview?

 

I tried with the buit-in harmonics analyzer, but it can not give the values of phase angle. I also tried the FFT spectrum VI,  but I don't think the results are right.

 

Thank you.

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A.Rohde
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Re: RMS/ magnitude and phase at fundamental frequency

Hi yiersan123

 

I'm not 100% sure if this is what you are looking for, if not you have to be more precise.

 

Please see if you can use the attached modified Harmonic Distortion Analyzer. Now called "Harmonic Distortion Analyzer and Phase". This should give both the components level and the components phase.

 

 

 

Best Regards

Anders Rohde

Applications Engineer

National Instruments Denmark

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yiersan123
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Re: RMS/ magnitude and phase at fundamental frequency

Hi Anders, thank you very much. This is for 1 channel signals. How can I change it to measure multi channel signals?

I'm using Labview to control an oscilloscope and measure and display the signals from 2 channels. So the signal I send to the harmonic VI contains the information from two channels.

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A.Rohde
Posts: 474
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Re: RMS/ magnitude and phase at fundamental frequency

Hi again

 

The Harmonic Distortion Analyzer is a polymorphic VI, this means that if you connect a single signal in then you get a single signal out, and if you connect an array of signals in the you get an array out.

 

The VI I have is not polymorphic, but you can easily change it to work with multiple signals. If you look at the standard implementation for the Harmonic Distortion Analyzer N-channels then it simply just calls the Harmonic Distortion Analyzer 1-channel in a for loop. So you can easily call my VI in the same fashion. See attached screenshot:

 

Harmonic Analyzer N-channels.PNG

 

 

 

Best Regards

Anders Rohde

Applications Engineer

National Instruments Denmark

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menomena
Posts: 36
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Re: RMS/ magnitude and phase at fundamental frequency

Is there any possibility to change that Harmonic Analyzer which counts phases and amplitudes of each harmonics but using 'pure FFT' not a 'FFT with hanning' ?? I dont know how to change that in VI. Can anyone help?