Creating and Manipulating Models

Referencing Channels by Name

You can also extract subsystems using I/O group or channel names. For example, if sys has an input group named noise, consisting of channels two, four, and five, then

• sys(1,'noise')
  

is equivalent to

• sys(1,[2 4 5])
  

Similarly, if pressure is the name assigned to an output channel of the LTI model sys, then

• sys('pressure',1) = tf(1, [1 1])
  

reassigns the subsystem from the first input of sys to the output labeled pressure.

You can reference a set of channels by input or output name by using a cell array of strings for the names. For example, if sys has one output channel named pressure and one named temperature, then these two output channels can be referenced using

• sys({'pressure','temperature'})
  

Referencing FRD Models Through Frequencies

Resizing LTI Systems