Examine Fig. P. 7.53, which shows three periodic functions and their corresponding Fourier frequency spectra. Discuss the graphs explaining what€™s happening in successive parts. What happens to the envelopes of the frequency spectra as the wavelength increases? Why are the same number of frequency terms present in each spectrum between 0 and, say, 4k? Why is there a DC term in each spectrum and why does it have the same value in all of them? Why are there no terms corresponding to A₂, A₄, A₆, and so forth?

Fig. P. 7.53

a.

b.

c.

f(x) . Ao . A1 * mk 4k 2k A = 0.5 f(x) . . Ao A1 A5 mk ol k 2kL-4k %3D 1.0