Example 3.F(S (b)
Example 3. 2 1 ( ) + = s s F s
S-2 FC(s-2 M P II(s-p) =M∠p ∠(S-=) (S-p1) △S-z △M= A=以A=∑A(s==)∑A(s-P) 中 contour F Contour 中r P2 P1 中 (b)
= − − = M s p s z F s i j ( ) ( ) ( ) − − = i j s p s z M =( − ) −( − ) j pi s z s − − = i j s p s z M =( − ) −( − ) j pi s z s
Cauchy's Theorem The encirclement of the poles and zeros of F(s) can be related to the encirclement of the origin in the F(s)-plane by Cauchy's theorem, commonly known as the principle of the argument, which state If a contour Is in the s-plane encircles Z zeros and P poles of f(s) and does not pass through any poles or zeros of f(s)and the traversal is in the clockwise direction along the contour, the corresponding contour TF in the f(s-plane encircles the origin of the F(S)- plane n=z-p times in the clockwise direction
• The encirclement of the poles and zeros of F(s) can be related to the encirclement of the origin in the F(s)-plane by Cauchy’s theorem, commonly known as the principle of the argument, which state: Cauchy’s Theorem • If a contour Γs in the s-plane encircles Z zeros and P poles of F(s) and does not pass through any poles or zeros of F(s) and the traversal is in the clockwise direction along the contour, the corresponding contour ΓF in the F(s)-plane encircles the origin of the F(s)- plane N = Z – P times in the clockwise direction
Ex. 4 Ts (a) J J Ex 5 (b)
Ex. 4 Ex. 5
Im F(s) 3|-2-1 Re f(s) Plot of F(sy .The image of the path encircling the zero encircles the origin once in the clockwise direction .The image of the path encircling the pole encircles the origin once in the counter-clockwise direction .The image of the path encircling neither does not encircle the origin