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Is there a peak width .vi

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I need to calculate the width of peaks in some data. I am currently using the calculation mentioned at this thread:

 

http://forums.ni.com/t5/LabVIEW/Peak-Width/m-p/382458?requireLogin=False

 

however I was just wondering is there any labview .vi or similar?

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The reason I ask is that using the method supplied in the aforementioned reports my peak widths as being reported as smaller than they actually are.

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How do you define peak width? Width at half height?

 

Show us some typical data and tell us what width you are expecting.

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An example is attatched. My software reports a FWHM of the max peak of around 1.8 however the actual peak width is more like 5. Unless I am doing the FHWM calculation incorrectly using the outputs from the peak finder .vi ?? The current calculation I am using is:

 

2*sqrt(-PEAK Amplitude/y") = Peak Width

 

which uses the amplitude and second derivative from the peak finder .vi

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Solution
Accepted by topic author eword

What is the difference between FWHM and FHWM?

 

You seem to have very few points defining your peak. Are they Gaussian, Lorentzian? Just looking at the graph, a value around 2 seems about correct.

 

If you think 5 is correct, maybe you want the width at 5% of maximum?

 

Remember, the full width at half maximum (FWHM) is the width at half the height of the peak (A) and not near the peak base (B) as you seem to think.

 

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Ok cheers for that.

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