Revision as of 10:32, 24 October 2008 by Twroblew (Talk)

Hello, This is my Homework 7 Contribution.

I am having some trouble still with the process of doing Fourier Transforms so I thought it would be a good idea to do some examples of how to do a Fourier Transform to help clarify the process.


Example 1


Lets take a simple example to start.


Lets let : $ x[n] = a^nu[n], |a| < 1\, $


Converting to $ X(e^{j\omega})\, $ notation we get


$ X(e^{j\omega}) = \sum^{\infty}_{n = -\infty} a^n u[n] e^{-j\omega n}\, $

Simplifying we get...

$ X(e^{j\omega}) = \sum^{\infty}_{n = 0} (ae^{-j\omega})^n\, $

$ X(e^{j\omega}) = \frac{1}{1-a e^{-j\omega}}\, $

This gives up a magnitude and phase graphs. Something noteworthy is that this function is periodic with an $ {\omega} = 2\pi\, $


Example 2


Let's try something a little more challenging.....

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