Environmental Engineering Reference
In-Depth Information
With the introduction of these two resistors the open-loop gain given in
(5.45) changes to
Observe that only modifies the denominator because changes the
zero of the inner amplifier. It is also clear that the numerator of (5.58) is
greatly different from that of (5.45) and now depends on
and
By
inspection of (5.58), it is possible to nullify the
term and to make the
s
term positive by choosing
In this manner, the residual LHP zero can be exploited to increase the phase
margin. However, we shall not further develop this approach because better
ones have been elaborated.
