# Convolutions, Fourier Series...

Discussion in 'Homework Help' started by eazhar, Mar 16, 2007.

1. ### eazhar Thread Starter New Member

Mar 16, 2007
2
0
Hi guys I just discovered this board and this will be my first post

The question on my homework reads:

Determine the Fourier Series representation of the signal x(t) = cos(2t+pi/4). If the impulse response of the system is h(t) = e^(-t)*u(t), what is the output y(t)?

I can find the fourier series representation of x(t) no problem. My question is, do you have to use that answer to evaluate the convolution, or are the two pretty much separate questions, using same signal?

2. ### DrNick Active Member

Dec 13, 2006
110
2
just compute the convolution intigral, OR you can take the laplace transform of both, multiply and do the inverse transform (because convolution in time => multiplication in frequency). These are two seperate questions.

3. ### Dave Retired Moderator

Nov 17, 2003
6,960
145
Agreed. This is the approach I would recommend you take.

Dave