6.1 Elementary Interconnections

Elementary interconnections include serial (cascade), parallel, and feedback interconnections. The subsystems can be supplied in either state-space or transfer function form. If of two subsystems one is in state space, the other is transformed to that form too, and a state-space object is returned. If both systems are entered as transfer functions, this is the form of the resultant system. If the transfer functions of the blocks are defined using differently named variables, the first variable encountered is used in the result. In elementary and other interconnections, inputs and outputs are referred to by their index in the input or output vectors.