# Graphing fequence of the signal

1. Nov 18, 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)

How would I graph F(W)?

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 F(W) for this?

2. Nov 18, 2013

### Simon Bridge

You wouldn't - no F(W) has been given.
You have an X(W) - which seems to be the fourier-series expansion of x(w) or something.
As it is written, it does not seem to depend on W though - but on w.
It helps if you say what things are.

Anyway - if your problem is to graph a sum of complex exponentials - you'd either plot the real and imaginary parts separately or plot the trajectory in the complex plane.

Again - no F(W) or any indication how it may be related to x or X. Same advise I guess.

3. Nov 18, 2013

### cutesteph

I mean X(F).

4. Nov 19, 2013

### Simon Bridge

I don't see any X(F) either.
What are these things supposed to represent?