Closed-loop transfer function

In control theory, a closed-loop transfer function is a mathematical function describing the net result of the effects of a feedback control loop on the input signal to the plant under control. 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 waveforms, , or other types of data streams. 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: is called feedforward transfer function, is called feedback transfer function, and their product is called the open-loop transfer function.