Thus, when we use the logaritluns of the gains, we obtain the overall
gain by just adding the logarithms of tile gains of the individual
elements. This enables us to consider any frequency response function as
being made up of a number of simple elements and so obtain the
response by adding the logarithms of the gains of the simple elements.
For example, we can think of the frequency response function 5/(2 + jco)
as being two elements, one with frequency response function 5 and the
other with frequency response function 1/(2 + jco).
Because we can obtain the Bode plot for a system by considering the
plots for the constituent elements of its frequency response function and
adding, it is only necessary to know the form of the Bode plots for a
small number of transfer function terms: