In our analyses, we assumed the small-signal condition given by Equation (4.4). Now consider Equation (4.3(b)) and

Question:

In our analyses, we assumed the small-signal condition given by Equation (4.4). Now consider Equation (4.3(b)) and let $v_{g s}=V_{g s} \sin \omega t$. Show that the ratio of the signal at frequency $2 \omega$ to the signal at frequency $\omega$ is given by $V_{g S} /\left[4\left(V_{G S}-V_{T N}\right)\right]$. This ratio, expressed in a percentage, is called the second-harmonic distortion. [Hint: Use the trigonometric identity $\sin ^{2} \theta=\frac{1}{2}-\frac{1}{2} \cos 2 \theta$.]