Here t is time, n is the number of the harmonic or mode (n=1 for the fundamental, 2 for the second harmonic etc.), An is the amplitude of harmonic or mode number n and \(f_{...Here t is time, n is the number of the harmonic or mode (n=1 for the fundamental, 2 for the second harmonic etc.), An is the amplitude of harmonic or mode number n and f1 is the fundamental frequency (f=1/T). You can also see the magnitude of the amplitude by holding the mouse the mouse button down and moving the mouse to the top of one of the peaks on the graph on the left.