Before revision: Therefore, one natural characterization of systems is by how many inputs and outputs they have: SISOSingle Input, Single Output SIMOSingle Input, Multiple Outputs MISOMultiple Inputs, Single Output MIMOMultiple Inputs, Multiple Outputs It is often useful (or necessary) to break up a system into smaller pieces for analysis.
After revision: Therefore, one natural characterization of systems is by how many inputs and outputs they have: SISOSingle input, single output SIMOSingle input, multiple outputs MISOMultiple inputs, single output MIMOMultiple inputs, multiple outputs It is often useful (or necessary) to break up a system into smaller pieces for analysis.