Andru

>> syms s;

>> num=(64*s^2+80*s+90)*(36*s^2+96*s+24)*(9*s^2+8*s+14)

num =

(9*s^2 + 8*s + 14)*(36*s^2 + 96*s + 24)*(64*s^2 + 80*s + 90)

>>den= s*(s+29)*(s+40)*(9*s^2+16*s+4)*(16*s^2+18*s+4)*(s^2+2*s+5)

den =

s*(s + 29)*(s + 40)*(s^2 + 2*s + 5)*(9*s^2 + 16*s + 4)*(16*s^2 + 18*s + 4)>> num=syms

>> num=sym2poly(num);

>> den=sym2poly(den);

>> G=tf(num,den)

Transfer function:

20736 s^6 + 99648 s^5 + 216552 s^4 +321024 s^3 + 278304 s^2

+ 165120 s + 30240---------------------------------------------------------------

144 s^9 + 10642 s^8 + 217698 s^7 + 956098 s^6 + 2.464e006 s^5

+ 3.637e006 s^4 + 2.634e006 s^3 + 831440 s^2 + 92800 s

>>bode(num,den)

[pic]

>> num=(s^2+9*s+8)*(36*s^2+24*s+18)*(63*s^2+29*s+18)

num =

(s^2 + 9*s + 8)*(36*s^2 + 24*s + 18)*(63*s^2 + 29*s + 18)

>> den=s*(s+6)*(s+40)*(9*s^2+8*s+12)*(64*s^2+40*s+99)*(s^2+4*s+6)

den =

s*(s + 6)*(s + 40)*(s^2 + 4*s + 6)*(9*s^2 + 8*s + 12)*(64*s^2 + 40*s + 99)

>>num=sym2poly(num);

>> den=sym2poly(den);

>> G=tf(num,den)

Transfer function:

2268 s^6 + 22968 s^5 + 43626 s^4 + 43704 s^3 + 28734 s^2 +10548 s + 2592

---------------------------------------------------------------------------------

576 s^9 + 29672 s^8 + 293259 s^7 + 1.187e006 s^6+ 2.823e006 s^5 + 4.308e006 s^4

+ 4.933e006 s^3 + 3.3e006 s^2 + 1.711e006 s

>> bode(num,den)

[pic]