MATLAB: Creating discrete-time model

#z-domain #discrete #discretemodel

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)

Best Answer

Use this line of code to get a negative exponent.

H = tf(P,Q,0.1,'variable','z^-1');

Related Solutions

MATLAB: Create a transfer function that looks like a polynomial

If you have filter cofficient, then you need to pass following options to tf()

C = [1 -1.047 0.558 0.2608 -0.7408 0.09526];
sys = tf(C, 1, .01, 'variable', 'z^-1')

Result

>> sys
sys =
 
  1 - 1.047 z^-1 + 0.558 z^-2 + 0.2608 z^-3 - 0.7408 z^-4 + 0.09526 z^-5
 
Sample time: 0.01 seconds
Discrete-time transfer function.

Note that, in this case, C must be a row vector.

In your question, you are using C as a column vector; therefore, you are getting five transfer functions with static gains.

MATLAB: Derivative of a function

(z - z1).*(z - z2).*(z - z3).*(z - z4) + (z - z1).*(z - z2).*(z - z3).*(z - z5) + (z - z1).*(z - z2).*(z - z4).*(z - z5) + (z - z1).*(z - z3).*(z - z4).*(z - z5) + (z - z2).*(z - z3).*(z - z4).*(z - z5)

Best Answer

Related Solutions

MATLAB: Create a transfer function that looks like a polynomial

MATLAB: Derivative of a function

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