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(a) A signal $A \sin \omega_m \mathrm{t}$ is input to a square - law device $\left(e_0-e_{m 2}\right)$. The output of which is given to an $\mathrm{FM}$ modulator as the modulating signal. The frequency deviation characteristics of the $\text{FM}$ modulator is $f=f_c+K e(t)$. Where $e(t)$ is the modulating signal and $\mathrm{K}$ is a constant. Determine the $\text{FM}$ signal and the frequency components in its spectrum.

(b) In the figure, $x(t)$ is the modulating signal and $t_c$ is the carrier frequency. Determine the value of gain $\mathrm{K}$ so that the output is a suppressed carrier $\text{DSB}$ signal.