Creating and Manipulating Models    

Addition and Subtraction

Adding LTI models is equivalent to connecting them in parallel. Specifically, the LTI model

represents the parallel interconnection shown below.

If sys1 and sys2 are two state-space models with data and , the state-space data associated with sys1 + sys2 is

Scalar addition is also supported and behaves as follows: if sys1 is MIMO and sys2 is SISO, sys1 + sys2 produces a system with the same dimensions as sys1 whose ijth entry is sys1(i,j) + sys2.

Similarly, the subtraction of two LTI models

is depicted by the following block diagram.


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