The group delay of the transfer function \(H\left( s \right) = \f

The group delay of the transfer function \(H\left( s \right) = \f
| The group delay of the transfer function \(H\left( s \right) = \frac{{s - 1}}{{s + 1}}\) is ______

A. &pi; &ndash; 2 tan<sup>-1</sup> (&omega;)

B. <span class="math-tex">\(\frac{1}{{1 + \omega }}\)</span>

C. <span class="math-tex">\(\frac{2}{{{\omega ^2} + 1}}\)</span>

D. 2 tan<sup>-1</sup> (&omega;)

Please scroll down to see the correct answer and solution guide.

Right Answer is: C

SOLUTION

\(H{\left( s \right)_{s = j\omega }} = \frac{{j\omega - 1}}{{j\omega + 1}} \)

\(\theta \left( \omega \right) = \pi - 2{\tan ^{ - 1}}\left( \omega \right)\)

\({t_g}\left( \omega \right) = \frac{{ - d\theta \left( \omega \right)}}{{d\omega }} = \frac{2}{{1 + {\omega ^2}}}\)