That doesn't look terse to me, though it does require familiarity with the subject. "The last expression can be interpreted as the Fourier superposition of the

That doesn't look terse to me, though it does require familiarity with the subject. "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.