Question

The sinusoidal signal is passed through a square law device defined by the input output relation $y\left(t\right)=x^2\left(t\right)$. The DC component in the signal $x\left(t\right)=4cos(200t+\pi /6)$ is______.

• A. 8

Answer 1

The correct option is A 8
$y\left(t\right)=4^{2}co{s}^2(200t+\frac{\pi }{6})$

$=4^2\cdot \frac{1+cos2(200t+\frac{\pi }{6})}{2}=8+8cos(400t+\frac{\pi }{3})$

Hence, DC component = 8