Waveform reconstruction in labview

[crewx]

I have an array of voltage values, (y axis) and an array of time values (x axis) and I would like to reconstruct a wave from from these values.

The time values are not evenly distributed, they range from 3 ms to 6 ms, the wave form frequency being reconstructed is about 125 hz.

Per the shannon-nyquist theorem, the required frequency of samples is 8 ms or less. 

Using labview 8.51 I would like to reconstruct the wave form, (currently I can plot it in the xy chart, but I want to do analyis on waveform)

In general you can use sin x/ x to reconstruct a waveform mathematically, I am looking for a tool that does this for me. 

Message Edited by crewx on 06-18-2009 03:04 PM

[GregFreeman]

If im not mistaken the point of the waveform chart is to graph based on evenly spaced time intervals. I'd post what you want to do as far as analysis and someone can probably help you do that analysis with an xy graph.

[crewx]

Yes, but I'd like to use the waveform tools, I need to resample the data with more points, get frequency, amplitude, phase, perform transformations etc. 

[eximo]

I would like to create a signal reconstruction filter.

as described her http://www.steepestascent.com/content/mediaassets/pdf/example%20resampling.pdf

I've gotten a few certifications with LabVIEW now, but still need some help here.  Assuming I have a 30 HZ signal, that was sampled at 10k HZ then resampled down to 125 HZ.

I would like to recreate the entire signal using the sinc function from the resampled points.

Any takers on this task?

[Anithasurulimuthu]

can someone suggest me how to connect the USRP output as an waveform to an vi....or how to reconstruct a waveform from samples per second

[GerdW]

Hi Anitha,

you should be creating your own thread instead of reviving this very old one…

- Creating a waveform is explained in the help of the waveform functions. And surely in example VIs coming with LabVIEW, too…

- What is the output of your "USRP"?

[Hatef.fouladi]

I so not really know if what i done is standard to do or not 
but what I done is kind of linear fitting to convert array with different time form 3 to 6 ms into waveform of 1 ms  dt
check this vi and I hope other Lv expert tell me that if this is right and allowable method to such work or not 

[GerdW]

Hi Hatef,

can you explain what your VI actually does?

And how it relates to the question raised here?

[Hatef.fouladi]

What I done is kind of fitting  based on data that I have

here we have data with different time zone from 3 up to 6 ms   I suppose wave with 1 ms time duration then I put my real data in the line of wave bead on their time and for data between these  data I regard one line progressing algorithm to create data between them because we just need real data with accuracy of 8 ms so I do not think it make any problem for us

[Hatef.fouladi]

What I done is kind of fitting  based on data that I have

here we have data with different time zone from 3 up to 6 ms   I suppose wave with 1 ms time duration then I put my real data in the line of wave bead on their time and for data between these  data I regard one line progressing algorithm to create data between them because we just need real data with accuracy of 8 ms so I do not think it make any problem for us