Fourier Transform question F o sin(10t)

**priscared** · Jun25-09, 02:30 AM

Hi all,
Can some1 explain how to get the complex fourier transform of sin(10t)

I understand how to steal it off a fourier transform table, but i have no idea how to do it manually.

Any help anyone?
Cheers

**daviddoria** · Jun25-09, 08:49 AM

The Fourier transform of a pure tone (the sine function) is two delta function, one at $LaTeX Code: +\\frac{10}{2\\pi}$ and the other at $LaTeX Code: -\\frac{10}{2\\pi}$ (I could have my $LaTeX Code: {2\\pi}$ 's wrong). The last part of this question should be a simple sampling in the frequency domain of the transform of the function in part A.

**priscared** · Jun26-09, 03:57 AM

thanks for your reply.
yeah i was way off. Thanks for the clarification

**priscared** · Jun26-09, 05:10 AM

Hi,
When answering question above, you stated the need "The last part of this question should be a simple sampling in the frequency domain of the transform of the function in part A."

I believe i have the right rule attached.

e^(j 2pi fc t)g(t) <-> G(f-fc) (this formula is attached in jpeg)

So, once i find the Fourier transform of the first function. I simply need to shift it by fc.

I have had a go at it, i think its right. (answer attached)

If you could point me in the right direction, that'd be great. cheers