spread sheet file to the formula loop

[KK54321]

I have a spectrum data wavelength vs intensity ranging from 600-800 nm, now i have to convert wavelength (x-axis) to wavenumber - i should get a wave number vs intensity output. I did the following code, But I see only first value is converted to wavenumber. Can anyone give me some suggestions to improve code.

[GerdW]

Hi KK,

---

@KK54321 wrote:

Can anyone give me some suggestions to improve code.

---

Use the AutoCleanup button to improve your code in the first step.

Then start to think about the algorithm you want to implement - and explain that algorithm to us so we can provide suggestions!

Right now I see:

• You read an array from your file and pick the first element of that array.
• Then you build an array from that single element, just to pick the first element again… (???)
• Using that element to run a FOR loop x times.
• Executing the same code in the loop x times, but only using the result of the last iteration. What's the point here?
• That last scalar result is again build into an array (of just one element), then that array is sorted: what's the point in this operation???
• Then the sorted array of float values is shown in an integer indicator: are you sure you display the expected values?
• Why do you need a formula node for this small math formula? Why not use plain G functions?

---

@KK54321 wrote:

I have a spectrum data wavelength vs intensity ranging from 600-800 nm, now i have to convert wavelength (x-axis) to wavenumber - i should get a wave number vs intensity output.

---

Please explain the term "wavenumber"!

How do you want to convert wavelength to "wavenumber"? Which algorithm is used for that conversion?

[KK54321]

Hi,

Thank you for your reply,

I created a below VI, which is now doing the following,

1. load the data from txt file (wavelength vs intensity data) and plot it in graph

2. converting the x-axis to wavenumber using Raman shift equation in formula loop

3. plotting wave number vs intensity in a graph and saving the data to a txt file. I feel this is working according to my plan. Bu I have a question  - I used for loop for formula loop but i did not use any iteration and give any command to n, but it still working.

So now I need to take the FFT of a wavenumber data which i got now and multiply it with Hann window and take IFFT - to get a clean spectrum.

Any suggestions will be highly appreciated. Attached the images for the above code.

[GerdW]

Hi KK,

---

@KK54321 wrote:

Any suggestions will be highly appreciated. Attached the images for the above code.

---

As you only attach images of code I will do the same:

No FOR loop needed!

Do yourself (and us) a favor and post real code next time! We cannot edit/debug/run images with LabVIEW…

[KK54321]

Hi,

Thank you for you help, I have implemented your suggestion. Now I am using this generated wave number vs intensity spectra to do the following steps,

wave number vs intensity spectrum

  I

FFT

  I

multiply with Hann window 

  I

IFFT

  I

final spectrum in waveform graph

Below I attached the VI, I could not see any output spectra after IFFT. maybe I made some mistake in the code, if possible could you help me with this.; I have attacked data file (wavelength vs Intensity) also.

Thank you

KK

[GerdW]

Hi KK,

please downconvert your VI to LV2021 or (even better) LV2019. (File->Save for previous)

Many long-time users of LabVIEW didn't upgrade to LV2022/LV2023 yet due to subscription license issues…

(Did you notice my signature line?)

[KK54321]

Hi GerdW,

Please see the attached down converted VI. please let me know if this is working or any modifications are needed.

Thank you

KK

[GerdW]

Hi KK,

---

@KK54321 wrote:

Please see the attached down converted VI. please let me know if this is working or any modifications are needed.

---

Now I'm missing your datafile…

Why do you need that sequence structure?

Why do you use those PtByPt-FFT functions? Do you know what PtByPt-functions are good for?

[KK54321]

Hi GerdW,

Please find the attached data file.first column is wavelength and second column is intensity.

Why do you need that sequence structure?

Why do you use those PtByPt-FFT functions? Do you know what PtByPt-functions are good for?

sorry about that, I am new to Labview, so using google and following previous Labview projects I made this code. Your suggestions are really help full.

Thank you

KK

[GerdW]

Hi KK,

see this: