Most sounds are composed of
more than one frequency at a time. In music, this is known as a chord. If this were not the
case, then we would be left with those annoying monophonic ringtones from the first cell phones.
You know, the ones where there were only 10 ringtones from which to choose and the odds of
more than one person having that annoying beeping rendition of Für Elise were very high. But I
digress.
In MATLAB, if we plot the amplitude data vector against time we get a plot similar to the one