Extract Single Tone Information using Flat Top Windowing

[aaronb]

Beginner here - Does anyone have any ideas on what would be the easiest way to create a function that would essentially perform the same function as the built in "Extract Single Tone Information.vi" only that instead of using Hanning windowing (as I noticed that this Vi does) I would be able to use Flat Top (or selectable windowing)? I basicly need to set something up that will accept an incoming Sine wave and apply FFT using Flat Top windowing then output the measured frequency and the amplitude of that frequency. I need to still be able to input the "advanced search" criteria into the VI and give it a frequency and tolerence to look for as I don't want to just look for the peak signal but at specific frequencies. 

[johnsold]

Open the Extract Single Tone Information.vi.  Save a copy of it with a different name to a location outside the vi.lib.  This is important - you do not want to change anything in vi.lib or it will cause lots of other problems!  Then edit the diagram of the copy to use the Flat top window.  Save edited version.

Lynn 

[aaronb]

I thought of that as well initially but I don't think that will work. Within Extract Single Tone Information.vi there is the sub-vi called "Extract Single Tone Information from Hann Spectrum.vi" which is NI password protected. I could be wrong but I don't believe there is another VI in the library called "Extract Single Tone Information from Flat Top Spectrum".

 

[johnsold]

I did not dig down to that level.

You may need to code your own.  Since you want to limit the search range, this may not be a simple task.  Do you have a good definition of the parameters you need to constrain and the nature of the signal you are measuring?

Lynn 

[pine]

Which LabVIEW are you using?

In 8.6, there is no password protected VIs. 

By the way, if you want to implement this function yourself, it will not be very difficult: 

1. Window and FFT, get amplitude spectrum and phase spectrum.

2. Get peak amplitude by peak detection.

3. Calculate  tone amplitude,phase and frequency.

Although it is different from NI pattented tone extraction method, this method can work well for normal cases (frequency not very big or very small). 

[Coq_Rouge]

Hi you can always do the copy and paste trick. Copy all content on the block diagram(Ctrl+a) and paste it into a new VI. Then reconstruct the connector pane. And save it. I think labview has taken protection a step to far in this case

Se file attached it is in 8.0

[aaronb]

I am running Labview 7.1.1 (that's what my company uses and they refuse to upgrade). I can't open files built under anything newer than LV7.1.1.

I really don't want to just do a peak search of the entire spectrum and would rather enter a specific frequency to look for and the tolerance window (find peak at say +/- 2% tolerance away from known recorded frequency. This test is targeted as a production test we will be shipping to several parteners around the world to use in production. This will be a test fixture to perform testing on electret boom microphones. The fact that it will be used in a production environment there is potential for high levels of background noise (radios, floresent lights, people talking, etc) and therefore I need as much filtering as possible to only the frequency i am trying to measure. I will be outputting a specific frequency from a speaker and recording it back through the microphone under test via a NI USB-6211 DAQ.

Can anyone tell me if "Extract Single Tone Information fron Hann Spectrum.vi" has anything in it which would limit me to only inputting a Hann windowed FFT into the signal input of that VI? This is the VI which is password protected in my 7.1.1. copy of Labview. If it doesn't and I could feed it a Flat Top windowed FFT signal into it without problem I am golden. I can modify the other sub-vi ("FFT with Hanning") and the main "Extract Single Tone Information 1CH.vi".

Thanks for you continued input. 

P.S. I am fairly new to Labview (<2yrs)

[Coq_Rouge]

Hi

The Vi i attached is the function you want but is 8.0. Sorry I do not have a version allowing saving in 7.1. But someone may save it 7.1 for you

I have included a print out for you.

[Kristen_K.]

Hi aaronb!

I have saved the VI to 7.1, so you should be able to load it.  Looks like one of the FFT VIs isn't available in 7.1, but should give you a good starting place, nonetheless.

Kristen H.