implement z in matlab simulink

[Serwan Bamerni]

Hi everyone

I have a simple question

How could one implement the z or z^2 in simulink? The z^−1, z^−2 could be implemented by Variable Integer Delay block, but what about z^2?

 

[CataM]

I tried to implement it like a simple Discrete Transfer Function making the coefficient of the "z" denominator 0 but it can't be. I think you can not implement such a thing like in "s" domain that is not possible to have more zeros than poles.

 

[Serwan Bamerni]

I tried to implement it like a simple Discrete Transfer Function making the coefficient of the "z" denominator 0 but it can't be. I think you can not implement such a thing like in "s" domain that is not possible to have more zeros than poles.

Thank you for your kind reply

Do you mean that I should not spend more time trying implementing z^2 or higher z power?

 

[CataM]

Do you mean that I should not spend more time trying implementing z^2 or higher z power?

Yes I think..

If you get a discrete transfer function which involves z^n (n=1,2,3..) is not possible to implement them. It is just like in the "s" domain that is not possible to have more zeros than poles even though mathematically we find some transfer function like that. What we have to do is to implement it in such a way that those z^n (n=1,2,3..) do not appear.

Of course, this is just for MATLAB because MATLAB do not allow us to implement such transfer functions, but by drawing block diagrams and simplifying them manually, finally we get the same result.

This is what I have found here: https://es.mathworks.com/help/simulink/slref/discretetransferfcn.html

The Discrete Transfer Fcn block implements the z-transform transfer function:
H(z)=num(z)/den(z)=...
where m+1 and n+1 are the number of numerator and denominator coefficients, respectively. num and den contain the coefficients of the numerator and denominator in descending powers of z. num can be a vector or matrix, den must be a vector, and you specify both as parameters on the block dialog box. The order of the denominator must be greater than or equal to the order of the numerator.