%% Extract Transfer Functions from Identified Model
% For this example, extract the measured and noise components of an identified polynomial model into two separate transfer functions.
% Load the Box-Jenkins polynomial model ltiSys in identifiedModel.mat.

load('identifiedModel.mat','ltiSys');

% ltiSys is an identified discrete-time model of the form: y(t)=\frac{B}{F}u(t)+\frac{C}{D}e(t), where \frac{B}{F} represents the measured component and \frac{C}{D} the noise component.
%
% Extract the measured and noise components as transfer functions.

sysMeas = tf(ltiSys,'measured') 
sysNoise = tf(ltiSys,'noise')

% The measured component can serve as a plant model, while the noise component can be used as a disturbance model for control system design.
% Copyright 2018 The MathWorks, Inc.