Subtract two discrete transfer functions (dtf1 - dtf2)
function subtract import Modelica; import Modelica_LinearSystems2.Math.Polynomial; import Modelica_LinearSystems2.TransferFunction; import Modelica_LinearSystems2.DiscreteTransferFunction; input DiscreteTransferFunction dtf1; input DiscreteTransferFunction dtf2; output DiscreteTransferFunction result; end subtract;