An Algorithm for Finding Approximate Symbolic Pole/Zero Expressions

The approximate pole/zero expressions are computed starting from the state or the “state-like” matrix. The attempts of open-circuit and short-circuit replacement of circuit elements are combined with those to cut row and column groups of the state matrix for poles or the “state-like” matrix for zeros, and with LR iterations. The expressions of all poles and zeros of a wide-band amplifier and an RLC band-stop filter are computed, obtaining significantly better results than those given by the best approach available, implemented in the Analog Insydes package.