Frequency Response

The Institute of Electrical and Electronics Engineers defines frequency response in stable, linear systems as

‘‘the frequency-dependent relation in both gain and phase difference between steady-state sinusoidal inputs

and the resultant steady-state sinusoidal outputs’’ (IEEE, 1988). The frequency-response characteristics of a

system can be found analytically from its transfer function. They are also commonly measured in laboratory or

field tests. A single-input/single-output linear time-invariant system is shown in Figure 11.1.