Contents
Practice Question on Computing the Fourier Transform of a Continuous-time Signal
Compute the Fourier transform of the signal
$ x(t) = e^{-t} u(t).\ $
You will receive feedback from your instructor and TA directly on this page. Other students are welcome to comment/discuss/point out mistakes/ask questions too!
Answer 1
$ \boldsymbol{\chi}(\omega)=\int_{-\infty}^\infty x(t)e^{-j\omega t}dt=\int_{-\infty}^\infty e^{-t} u(t)e^{-j\omega t}dt=\int_{0}^\infty e^{-t(j\omega+1)}dt=\frac{e^{-t(j\omega+1)}}{-(j\omega+1)}\Bigg|_0^\infty=\frac{e^{-\infty}}{-(j\omega+1)}-\frac{e^{0}}{-(j\omega+1)}=\frac{1}{j\omega+1} $
$ \boldsymbol{\chi}(\omega)=\frac{1}{j\omega+1} $
--Cmcmican 02:31, 19 February 2011 (UTC)
- Instructor's comments: Good! Notice that, in contrast with the first example we did in class, you did not have to worry about the denominator being zero for certain values of the frequency. -pm
Answer 2
Write it here.
Answer 3
Write it here.
