Addition and Subtraction :: Operations on LTI Models (Creating and Manipulating Models)

Creating and Manipulating Models

Addition and Subtraction

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

```
sys = sys1 + sys2
```

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

```
sys = sys1 - sys2
```

is depicted by the following block diagram.

Arithmetic Operations on LTI Models Multiplication