Environmental Engineering Reference
In-Depth Information
A.2 APPROXIMATED POLES
In many practical circumstances it is useful to approximate the complete
transfer function with a second-order one
and when the two poles are real, which holds for
we can rewrite
relationship (A.6) as shown below
where
and the poles are related to coefficients
through [MG87]
[GT86],
By adding the condition of dominant-pole behaviour, which means
relationships (A.8) lead to a simple and useful relation between
poles and coefficients
The approach can be extended to higher-order functions with real and
well spaced poles [MG87].
