Editing Closed-loop transfer function (section)

== Overview ==
The closed-loop [[transfer function]] is measured at the output. The output signal can be calculated from the closed-loop transfer function and the input signal.  Signals may be [[waveform|waveforms]], [[image|images]], or other types of [[data stream|data streams]].

An example of a closed-loop block diagram, from which a transfer function may be computed, is shown below:

[[Image:Closed Loop Block Deriv.png]]

The summing node and the ''G''(''s'') and ''H''(''s'') blocks can all be combined into one block, which would have the following transfer function:

: <math>\dfrac{Y(s)}{X(s)} = \dfrac{G(s)}{1 + G(s) H(s)}</math>

<math>G(s) </math> is called the [[Feed forward (control)|feed forward]] transfer function, <math>H(s) </math> is called the [[Feedback#Control theory|feedback]] transfer function, and their product <math>G(s)H(s) </math> is called the '''open-loop transfer function'''.