Creating discrete-time model
2 views (last 30 days)
Show older comments
Jasmina Zukorlic
on 28 May 2018
Commented: Star Strider
on 29 May 2018
Hello, can someone please tell me what am I doing wrong in writing this expression in MATLAB:
This is the result I'm obtaining: H =
8 z^5 - 5 z^4 - 4 z^3 + z^2 + 3 z - 2
----------------------------------------------------------------------
0.0648 z^6 + 0.1134 z^5 - 0.6184 z^4 + 1.436 z^3 - 1.7 z^2 + 1.6 z - 1
And here is my code:
Nd=[-8 5 4 -1 -3 2];
Dd=[-0.0648 -0.1134 0.6184 -1.436 1.7 -1.6 1 ];
P=Nd;Q=Dd;
H = tf(P,Q,0.1)
1 Comment
Star Strider
on 29 May 2018
If you want to code the transfer function in the image you posted, you need to enter the coefficients in the correct order. Here, that means using fliplr (since I do not want to re-type the vectors):
Nd = [-8 5 4 0 -1 -3 2];
Dd = [-0.0648 -0.1134 0.6184 -1.436 1.7 -1.6 1 ];
P = fliplr(Nd);
Q = fliplr(Dd);
H = tf(P,Q,0.1,'variable','z^-1')
H =
2 - 3 z^-1 - z^-2 + 4 z^-4 + 5 z^-5 - 8 z^-6
------------------------------------------------------------------------------
1 - 1.6 z^-1 + 1.7 z^-2 - 1.436 z^-3 + 0.6184 z^-4 - 0.1134 z^-5 - 0.0648 z^-6
Sample time: 0.1 seconds
Discrete-time transfer function.
Accepted Answer
Abraham Boayue
on 28 May 2018
Use this line of code to get a negative exponent.
H = tf(P,Q,0.1,'variable','z^-1');
0 Comments
More Answers (0)
See Also
Categories
Find more on Logical in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!