Graphing amplitudes

1. Nov 19, 2013

cutesteph

Say x(n) = n for 0 <= n < 4 and 0 o.w.

So X(W) = Sum n=-∞ to ∞ x(n) exp(-inw) = sum from n=0 to 3 nexp(-inw)
= 0 + exp(-iw) + 2exp(-j2w) + 3 exp(-j3w)

get do I get the amplitude and phase?

Also if the signal was continuous x(t) = t for the same interval

X(W)= integral 0 to 4 texp(-iwt) dy = (4exp(-i4w)/ -iw) - (exp(-iw4) -1)/w^2

How would I graph the amplitude and phase?

Last edited: Nov 19, 2013
2. Nov 19, 2013

Simon Bridge

Is this related to your other thread: https://www.physicsforums.com/showthread.php?t=723594

What is it about the graph that is giving you trouble?
I presume you know how to draw axes and mark them off etc...

Perhaps you don't know how to find the real and imaginary parts of X.
Hint: http://en.wikipedia.org/wiki/Euler's_formula]Euler's[/PLAIN] [Broken] formula).

Note: when you write X(W) we usually expect X to be a function of W ... which means that some W's should appear on the RHS. You appear to have X(w).

Last edited by a moderator: May 6, 2017
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