Example of Computation of Fourier series of a CT SIGNAL
A practice problem on "Signals and Systems"
Periodic CT Signal
The first signal that comes to mind when i think of a periodic CT signal is one involving sines and cosines, so let's work with one of those.
Let $ x(t) = sin(14t)+(1+3j)cos(2t) $
This can also be expressed as
$ x(t) = \frac{e^{14jt}}{2j}-\frac{e^{-14jt}}{2j} + \frac{(1+3j)*e^{2jt}}{2} + \frac{(1+3j)e^{-2jt}}{2} $
I contend that the $ \omega_0=2 $ since both functions are periodic based on it.
$ a_7=\frac{1}{2j} $
$ a_{-7} = \frac{-1}{2j} $
$ a_1 = \frac{1+3j}{2} $
$ a_{-1} = \frac{1+3j}{2} $
We can write this as a sum:
$ x(t)=\sum^{\infty}_{k = -\infty} a_k e^{j2k}\, $
Where
$ a_1=a_{-1}=\frac{1+3j}{2} $
$ a_7 = -a_{-7} = \frac{1}{2j} $
$ a_k = 0, k \neq 1, -1, 7, -7 $
