"The last expression can be interpreted as the Fourier superposition of the sinusoidal harmonics of [expression], i.e., an inverse Fourier series sum. In other words, [expression] is the amplitude of the k-th harmonic in the Fourier-series expansion of the periodic signal x_m(t)."

Many of the concepts are hyperlinked for reference. With the required familiarity, I would much rather read this than something that took seven pages to get to the point - say by assuming that the reader is unfamiliar with a premise out of an abundance of caution.