A modulated signal $C_m(t)$ has the form $C_m(t)=30 \; \sin \; 300πt+10\; (cos 200πt −\cos 400πt)$. The carrier frequency $f_c$, the modulating frequency (message frequency) $f_ω$, and the modulation index $µ$ are respectively given by :

Question

$\begin{array}{1 1}(1) f_c = 200Hz; f_w = 50Hz; \mu = \frac{1}{2} \\ (2) f_c = 150Hz; f_w = 50Hz; \mu = \frac{2}{3} \\ (3) f_c = 150Hz; f_w = 30Hz; \mu = \frac{1}{3} \\ (4) f_c = 200Hz ; f_w = 30Hz; \mu = \frac{1}{2}\end{array}$