Rational Discrete Time Element (G(z))¶
The G(z) element is the general implementation of a linear discrete time transfer element. It is the counterpart to the analog G(s) element and is also known as digital controller.
A real time computer program must be causal, i.e. for computing the new output value y(kT), one can only use the input values u(kT), u(kT-T), ... From that is concluded that the order of the denominator must be greater or equal to the order of the numerator.
Functions

m ≤ n; m ≤ 31;
an≠0; n ≤ 31;
The meaning of the initial values is depicted by the matrix representation of the state equations:


; 