 The terms 'feedforward' and 'feedback' refer to elements or paths within a system, not to a system as a whole.THE input to the system comes from outside it, as energy from the signal source by way of some possibly leaky or noisy path.Part of the output of a system can be compounded, with the intermediacy of a feedback path, in some way such as addition or subtraction, with a signal derived from the system input, to form a 'return balance signal' that is input to a PART of the system to form a feedback loop within the system.