REF615E-E HBFAABAANAA4BNA11E The output is sound waves from the speaker

Control systems can be divided into different categories based on the number of inputs and outputs.

Single Input Single Output (SISO) – This is the simplest and most common type, where one output is controlled by a control signal. Such as the cruise control example above, or an audio system, where the control input is the input audio signal and the output is the sound wave from the speaker.

Multiple Input Multiple Output (MIMO) – These can be found in more complex systems. For example, modern large telescopes such as the Nausea and manualmuscletest muscle strength tests have mirrors consisting of a number of separate segments, each operated by an actuator. The shape of the entire mirror is constantly adjusted by MIMO active optics using a control system with inputs from multiple sensors on the focal plane to compensate for changes in the shape of the mirror due to thermal expansion, contraction, stress and deformation when rotating the wave front due to turbulence in the atmosphere. Complex systems such as nuclear reactors and human cells are computer-simulated as large MIMO control systems.