fast fourier transform from sampled values of a wave

[janetajaj]

Hi,

im new to labview .I'm trying to plot frequency spectrum of a FFT. here fft should be constructed using sampled values of a wave stored in spreadsheet. can any one help

[GerdW]

Hi Jane,

fft should be constructed using sampled values of a wave stored in spreadsheet.

Read the spreadsheet data, construct a waveform with this data, then apply a FFT function, plot the result by wiring to a graph. Finished.

can any one help

Well, where are you stuck?

We don't do homework, but we will answer any (specifc) question we can. So post your VI, attach your spreadsheet, tell us your problems/error messages…

im new to labview

Then I guess you already did the free online courses to learn the basics?

Btw. LabVIEW is written with some uppercase characters… 😄

[RavensFan]

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@GerdW wrote:

Btw. LabVIEW is written with some uppercase characters… 😄

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True.  And also the first letter of the first word of any sentence should be capitalized.

[janetajaj]

HI GerdW, Thank you for answering and correcting.As you said I read values from spreadsheet to an array using Read From Spreadsheet File.vi. Now i have to create a signal using these values .Is there any functionality in labVIEW to do this? Signal should have a frequency of 50 Hz. sampling frequency 2 Hz. I want to apply the generated signal to  FFT Power Spectrum.vi . I want to attach my VI and spreadsheet but i dont know how to attach multiple files. Thank you

[GerdW]

Hi janetajaj,

Now i have to create a signal using these values .Is there any functionality in labVIEW to do this?

BuildWaveform…

Signal should have a frequency of 50 Hz. sampling frequency 2 Hz.

This will not work according to work of Nyquist and Shannon…

[janetajaj]

Hi GerdW

Signal should have a frequency of 50 Hz. sampling frequency 2 Hz.

This will not work according to work of Nyquist and Shannon…

you are right , actually sampling rate is 2 KHz.Is it possible to input sampling frequency?

[GerdW]

Hi janetajaj,

when you would use the BuildWaveform function you would get the option to specify the sampling frequency (aka sampling time dt). And you would NOT get that read coercion dot…