A message $m(t)$ bandlimited to the frequency $f_{m}$ has a power of $P_{m}$. The power of the output signal in given figure is
- $\frac{\mathrm{P}_{m} \cos \theta}{2}$
- $\frac{\mathrm{P}_{m}}{4}$
- $\frac{P_{m} \sin ^{2} \theta}{4}$
- $\frac{P_{m} \cos ^{2} \theta}{4}$