This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
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# SystemsModelExtract

 SystemsModelExtract extracts the subsystem of the StateSpaceModel or TransferFunctionModel object sys associated with inputs at position . SystemsModelExtract extracts the subsystem associated with inputs and outputs at positions and , respectively. SystemsModelExtract extracts the subsystem of a StateSpaceModel object ss associated with inputs, outputs, and states at , , and , respectively.
• The specifications of the inputs, outputs, and states can also be All or None.
Extract the subsystem associated with the first input and third output:
Extract the subsystem associated with the first two states:
Extract the subsystem associated with the first input and third output:
 Out[1]=

Extract the subsystem associated with the first two states:
 Out[1]=
 Scope   (5)
Extract the subsystem associated with the first input of a three-input system:
The subsystem associated with the second output:
Extract the subsystem corresponding to the first and second inputs, and the third and fourth outputs:
Extract the subsystem associated with the second and third states of a state-space model:
The subsystem associated with the third and fourth states:
 Applications   (4)
Rearrange the inputs of a system:
Rearrange outputs:
Rearrange states:
Use SystemsModelExtract to obtain the responses of individual subsystems of a MIMO system:
The output response to a unit step input for each subsystem:
The output response of all the subsystems:
The Nyquist plots for each subsystem:
Visualize the response of specific outputs to specific inputs for a MIMO system:
The response of the outputs to a unit step applied only to the first input:
The response of the second output to excitations in both inputs:
In some cases it is possible to extract the controllable and observable subsystems of a model by visual observation:
Only the first three modes are controllable:
ControllableDecomposition gives the same result:
Only modes 2 and 3 are observable:
ObservableDecomposition gives the same result:
The specifications in SystemsModelExtract and SystemsModelDelete are complementary:
New in 8