I have a little problem with the subject Theory of signal. We were told to make amplitude and phase spectrum of cosinus in MATLAB, but we don't have results nor materials from our teachers, so we have to study from many different materials and you can imagine what this is like. So I'm a little confused.
However, I did some graphs, that should be what I want, according to instructions, but I have never seen something like that, so I'm not sure, if that's right.
Do these graphs make any sense to you? I used fast Fourier transform (fft(y) in MATLAB) on the signal and then plot the result of transform versus sample frequency and I thought it's possible to get phase of the signal by angle(fft(y)), so I plotted this on the last graph.
I would like to apologize for incorrect notions I might use, 'cause I'm not a native english speaker.
Thanks for any help.