2. Feedback
Components of a feedback system
❚ data on the actual level of some measurable attribute;
❚ data on the reference level of that attribute;
❚ a mechanism for comparing the two levels and generating information
about the ‘gap’ between the two levels;
❚ a mechanism by which the information can be used to alter the gap.
To an engineer, information is therefore feedback only if the information
fed back is actually used in closing the gap.
