Prob. 2

(a) In an FM system it is required that all the modulated signal power be concentrated in the sidebands and no power be transmitted at the carrier frequency.

What is the smallest value that ß can take? What is the power in the first sideband for this value of the modulation index?

(b) A carrier is modulated by two sinusoidal modulating signals so that the FM signal is given by

Dem(t) = Acos(2nfct + Busin2nfit + B2 sin2nfzt)

Show that the modulated signal has sidebands separated from the carrier not only at multiples of fı and of f but also has sidebands as well as separations of multiples of f1 + f2 and fı - f2.