hello,

I need to apply Laplace transform on this signal

and i'm just stuck with this one :D so can anybody please help me with this :D

any help will be most appreciated :D:D:D

Printable View

- Nov 9th 2010, 07:19 AMmaliZelenii need help with applying Laplace transform
hello,

I need to apply Laplace transform on this signal

and i'm just stuck with this one :D so can anybody please help me with this :D

any help will be most appreciated :D:D:D - Nov 9th 2010, 07:21 AMAckbeet
Well, the LT is linear, correct? So you should be able to move the Laplace Transform operator inside the sum. What's the LT of the Dirac Delta function you have in there?

- Nov 9th 2010, 07:29 AMmaliZeleni
- Nov 9th 2010, 07:33 AMAckbeet
Technically, you'd have

where is the Heaviside step function.

Now what? - Nov 9th 2010, 07:43 AMmaliZeleni
- Nov 9th 2010, 07:44 AMAckbeet
No, no. You're done with the LT. You should plug these results back into your original equation. What do you get?

- Nov 9th 2010, 07:50 AMmaliZeleni
- Nov 9th 2010, 07:55 AMAckbeet
What is T? Is is positive? If so, you can lose the Heaviside step function (it'll just be 1 everywhere). What do you have on the LHS of this equation? Finally, assuming you can ignore the step function, you can rewrite the sum this way:

Does that suggest anything to you?

It's true that the*sequence*probably converges to zero. But that doesn't mean the*series*

converges to zero. - Nov 9th 2010, 08:05 AMmaliZeleni
- Nov 9th 2010, 08:08 AMAckbeet
- Nov 9th 2010, 08:21 AMmaliZeleni
- Nov 9th 2010, 08:23 AMAckbeet
Well, you should probably have a lower-case s in there, but yes. However, you also need to do the LT of the LHS of the original equation in the OP. That's so hard it's easy:

Make sense? - Nov 9th 2010, 08:27 AMmaliZeleni
- Nov 9th 2010, 08:29 AMAckbeet
Oh, sorry. I didn't know. Your English is better than some native speakers I've seen.

LHS = Left Hand Side

RHS = Right Hand Side

LT = Laplace Transform

Cheers.