where M(ω) is the Fourier transform of the modulating signal m(t).
Shown in Fig. 17.23 is the frequency spectrum of the AM signal. Figure
17.23 indicates that the AM signal consists of the carrier and two other
sinusoids. The sinusoid with frequency ωc − ωm is known as the lower
sideband, while the one with frequency ωc + ωm is known as the upper
sideband.