Plotting in the frequency domain

Hi there, long time no maple use for me and I can't get my head around plotting the audio spectra of a function defined by

a:=sin(880* Pi *t + I * sin(880* Pi*t));

which relates amplitude to time. I want to put this in the form of a spectra that relates amplitude to frequency using maple, for various I. What I'd like to generate is something similar to File:Frequencymodulationdemo-fd.png - Wikipedia, the free encyclopedia, although even just a series of vertical lines would do it. If someone could help me set that up that'd be great.