A closed-loop transfer function
in control theory
is a mathematical expression (algorithm
) describing the net result of the effects of a closed (feedback
on the input signal
to the circuits enclosed by the loop.
The closed-loop transfer function
is measured at the output
. The output signal waveform
can be calculated from the closed-loop transfer function and the input signal waveform.
An example of a closed-loop transfer function is shown below:
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:
Let's define an intermediate signal Z shown as follows:
Using this figure we can write