>> n=1;
>> s=tf('s');
>> GPD=(n/4*s+1)
 
Transfer function:
0.25 s + 1
 
>> G_rat=((-1)^n)/((n-0.5)/(n+0.5)*s^2+s+(n+0.5)/(n-0.5))
 
Transfer function:
        -1
------------------
0.3333 s^2 + s + 3
 
>> G_dt=exp(-n/4*s)
 
Transfer function:
exp(-0.25*s) * (1)
 
>> G_m=1/(s+(n-0.5)/(n+0.5))
 
Transfer function:
    1
----------
s + 0.3333
 
>> G_OL=GPD*G_rat*G_dt*G_m
 
Transfer function:
                           -0.25 s - 1
exp(-0.25*s) * ------------------------------------
               0.3333 s^3 + 1.111 s^2 + 3.333 s + 1
 
>> dcgain(G_OL)

ans =

    -1

>> [Wn,Z,P] = damp(Gp)
??? Undefined function or variable 'Gp'.

>> [Wn,Z,P] = damp(G_OL)

Wn =

    0.3333
    3.0000
    3.0000


Z =

    1.0000
    0.5000
    0.5000


P =

  -0.3333          
  -1.5000 + 2.5981i
  -1.5000 - 2.5981i

>> zero(G_OL)

ans =

    -4

>> pole(G_OL)

ans =

  -1.5000 + 2.5981i
  -1.5000 - 2.5981i
  -0.3333          

>> bode(G_OL)