Re: test this in matlab for my please

[Nicholas Jankowski]

On Mon, Jun 13, 2016 at 10:13 AM, Doug Stewart <address@hidden> wrote:

Thanks again for your help.

I have some "normal' transfer function giving me the correct 

answer now, but I need someone to test these in Matlab.

  

s=tf("s")

T=.1

sys=1/(s*s*(s+1))

out2=c2d(sys,T,"impulse")

 

G = 3/((s+20)*(s+10))

outg=c2d(G,T,"impulse")

  

  

G2 = (s+3)/((s+20)*(s+10))

outg2=c2d(G2,T,"impulse") 

 

H=15/(s*(s+10)*(s+20))

 outh=c2d(H,T,"impulse")

 

 H1=15/(s*s*(s+10)*(s+20))

 outh1=c2d(H1,T,"impulse")

 s=tf("s")
      ↑
Error: The input character is not valid in MATLAB statements or expressions.

CTRL-H'ing all the double quotes:

>> s=tf('s')

s =
 
  s
 
Continuous-time transfer function.

>> T=.1

T =

    0.1000

>> sys=1/(s*s*(s+1))

sys =
 
      1
  ---------
  s^3 + s^2
 
Continuous-time transfer function.

>> out2=c2d(sys,T,'impulse')

out2 =
 
  0.0004837 z^2 + 0.0004679 z + 1.039e-18
  ---------------------------------------
     z^3 - 2.905 z^2 + 2.81 z - 0.9048
 
Sample time: 0.1 seconds
Discrete-time transfer function.

>> G = 3/((s+20)*(s+10))

G =
 
         3
  ----------------
  s^2 + 30 s + 200
 
Continuous-time transfer function.

>> outg=c2d(G,T,'impulse')

outg =
 
   0.006976 z + 2.42e-19
  ------------------------
  z^2 - 0.5032 z + 0.04979
 
Sample time: 0.1 seconds
Discrete-time transfer function.

>> G2 = (s+3)/((s+20)*(s+10))

G2 =
 
       s + 3
  ----------------
  s^2 + 30 s + 200
 
Continuous-time transfer function.

>> outg2=c2d(G2,T,'impulse')

outg2 =
 
    0.1 z^2 - 0.05307 z
  ------------------------
  z^2 - 0.5032 z + 0.04979
 
Sample time: 0.1 seconds
Discrete-time transfer function.

>> H=15/(s*(s+10)*(s+20))

H =
 
           15
  --------------------
  s^3 + 30 s^2 + 200 s
 
Continuous-time transfer function.

>>  outh=c2d(H,T,'impulse')

outh =
 
  0.002997 z^2 + 0.001102 z + 5.737e-21
  -------------------------------------
   z^3 - 1.503 z^2 + 0.553 z - 0.04979
 
Sample time: 0.1 seconds
Discrete-time transfer function.

>>  H1=15/(s*s*(s+10)*(s+20))

H1 =
 
            15
  ----------------------
  s^4 + 30 s^3 + 200 s^2
 
Continuous-time transfer function.

>>  outh1=c2d(H1,T,'impulse')

outh1 =
 
  0.0001261 z^3 + 0.0002556 z^2 + 2.83e-05 z + 2.497e-20
  ------------------------------------------------------
     z^4 - 2.503 z^3 + 2.056 z^2 - 0.6028 z + 0.04979
 
Sample time: 0.1 seconds
Discrete-time transfer function.