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I have a function $\sin(2\pi\cdot f\cdot t)$ where $t$ is the time domain and $f$ is the frequency.I must represent the fourier transform of this function in polar and cylindrical coordinates. I can tell you how did I proceed but i don't know if it's ok. I made the $\operatorname{fft}(\sin(2\pi\cdot f\cdot t))$ and I used $[\theta,r]=\operatorname{cart2pol}(x,y)$ function to obtain $r$ and $\theta$. $x$ and $y$ are the cartesian coordinates. My question is: who is $x$ and who is $y$ in my case? i chose $x$ the frequency and $y$ the amplitude. Is this ok?

Michael Hardy
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Toader
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Help $cart2pol$. Your signal has a frequency $f_0$ not $f$. It is a $1D$ time signal with sinusoidal amplitude. When you transform it you will get a Dirac function at $f=f_0$. Your function then will have an amplitude and frequency. I woul guess only that $x=f_0$ and $y=1$ for $cart2pol$

Seyhmus Güngören
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  • I understood.thank you for the answer. – Toader Mar 20 '13 at 13:15
  • @Toader my pleasure. If you liked this site and want to ask more questions, then I can suggest you to check "http://meta.math.stackexchange.com/". You can search there some faq s especially about "how to ask a question", "what to ask and what not to ask". "which sort of formatting is used to type a question", "how to type in tex", "what do upvoting, downvoting and accepting an answer mean?", "what sort of style we should follow when we ask a question, etc..". Welcome again to MSE. – Seyhmus Güngören Mar 20 '13 at 19:32
  • Thank you very much for the answer and for the advice.I would like to ask you one more question.I have to represent the fourier transform for a 2D signal, for exemple sin(2x+3y).who are x and y and how can I obtain this graphically?Thanks a lot. – Toader Mar 20 '13 at 20:10