# Graphing the Trigonometric Fourier spectra

#### nyasha

Joined Mar 23, 2009
90 So l just need to be pointed in the right direction and the rest l will do myself. How do l get the amplitude and phase for ω=2t. There is a sine and cosine with ω=2t. How do l deal with them.

#### chrisw1990

Joined Oct 22, 2011
551

#### nyasha

Joined Mar 23, 2009
90
http://webpages.dcu.ie/~applebyj/ms224/BT2_FSER.pdf
have a look, might be useful, might not, been a year or so since i did fourier at uni and i hated with a passion, maybe that was just the lecturer.. probably the lecturer

I do understand how to get the Fourier series. The given signal is a already a calculated fourier series they just want it to sketch its Fourier spectra. I am confused on what to do at ω=2t

#### MrChips

Joined Oct 2, 2009
21,399
I am confused on what to do at ω=2t
You probably meant to say at ω=2.

The amplitude would be the square-root of the sum of squares:

$$\sqrt{(\sqrt{3})^2 + 1^2} = \sqrt{4} = 2$$

See if you can figure out the phase on your own.

#### nyasha

Joined Mar 23, 2009
90
You probably meant to say at ω=2.

The amplitude would be the square-root of the sum of squares:

$$\sqrt{(\sqrt{3})^2 + 1^2} = \sqrt{4} = 2$$

See if you can figure out the phase on your own.
And the phase is 30 degrees. I now get it. Thanks man.

#### MrChips

Joined Oct 2, 2009
21,399
Well the phase angle is either 30 or 60 degrees. Try to figure out which is the correct answer.