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Topic: fft, sampling frequency, wavelength
Replies: 13   Last Post: Apr 17, 2012 2:22 AM

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 Solbohak Posts: 8 Registered: 3/13/12
Re: fft, sampling frequency, wavelength
Posted: Apr 12, 2012 4:59 AM

> Given the fft of a real-valued waveform with a length of N evenly
> spaced points, the frequency of a peak at the ith point 1<= i <=
> ceil((N+1)/2) will be a fixed fraction of the the sampling frequency
> Fs.
>
> f = (Fs/N)*[ 0:ceil( (N-1)/2 ) ];
> f0 = (Fs/N)(i-1) ;
>
> So, doubling Fs doubles f0, etc.
>
> Greg

Hi Greg,

shouldn't the frequency peaks not change their position on the frequency-axis !?

Could you do fft of the wave (vector a) and tell me what you get? Please!!!

here the needed facts again:

The data genarator produces 61 elements in a second. So the whole length of the vector "a" represent a total time of 50/61=0.82 seconds.

I am grateful for your help.

Solbohak

Date Subject Author
3/13/12 Solbohak
3/13/12 Derek Goring
3/13/12 Greg Heath
3/27/12 Solbohak
3/27/12 Greg Heath
3/27/12 Solbohak
3/27/12 Derek Goring
3/27/12 Solbohak
3/28/12 Solbohak
4/10/12 Solbohak
4/10/12 Greg Heath
4/12/12 Solbohak
4/12/12 Greg Heath
4/17/12 Solbohak