16.2 Causal Stable LTI-Systems 39 t, t I I A Figure 16.2: Pole-zero plots for stalile and unstable systems 16.2.3* S colltilluous Systems For continuous systems we will describe Hurwitz’s stability criteria It does not irivolvr searching for zeros, arid directly tises t h e cocKicients of the nominat,or ~ ? o l ~ i ~ o ~i fiii the i a l trassfcr function To use it we put the transfer function in the forrii (16.15) so that the numerator polyriomial (16.16)