the feedback loop is part of the linear model of communication
Models of communication This is a one-way model to communicate with others. It consists of the sender encoding a message and channeling it to the receiver in the presence of noise. In this model there is no feedback or response which may allow for a continuous exchange of information (F.N.S. Palma, 1993).
Frequency response Frequency response is the quantitative measure of the output spectrum of a system or device in response to a stimulus, and is used to characterize the dynamics of the system. It is a measure of magnitude and phase of the output as a function of frequency, in comparison to the input. In simplest terms, if a sine wave is injected into a system at a given frequency, a linear system will respond at that same frequency with a certain magnitude and a certain phase angle relative to the input. Also for a linear system, doubling the amplitude of the input will double the amplitude of the output. In addition, if the system is time-invariant (so LTI), then the frequency response also will not vary with time. Thus for LTI systems, the frequency response can be seen as applying the system's transfer function to a purely imaginary number argument representing the frequency of the sinusoidal excitation.[1]