SuperNomad
Aug14-10, 06:05 PM
So I'm doing some signal processing and I want to take a signal and find the frequency components and so I need to do the discrete fourier transform. The problem is I'm not sure how about to go about finding them. I'm using excel at the moment just because I vaguely know how to use it.
Anyway as an example I thought I'd try and find the frequency components of a sine wave, there should only be 1 and it should be 1/2pi.
Here is a screenshot of the excel sheet.
http://yfrog.com/5nexcelfftp
What I've done is created a sine wave, taken the FFT using the data analysis add-on, then taken the modulus using the "IMABS" function and plotted it as a line graph. You can see an appropriate spike though the numbers are meaningless. I imagine you see two spikes because of the periodic nature of the fourier transform. What do I have to do next to find the frequency?
Edit: Forgot to mention I would be incredibly grateful if anyone can help me!
Anyway as an example I thought I'd try and find the frequency components of a sine wave, there should only be 1 and it should be 1/2pi.
Here is a screenshot of the excel sheet.
http://yfrog.com/5nexcelfftp
What I've done is created a sine wave, taken the FFT using the data analysis add-on, then taken the modulus using the "IMABS" function and plotted it as a line graph. You can see an appropriate spike though the numbers are meaningless. I imagine you see two spikes because of the periodic nature of the fourier transform. What do I have to do next to find the frequency?
Edit: Forgot to mention I would be incredibly grateful if anyone can help me!