Pole/Zero Computation for Linear Circuits

An algorithm able to compute both the numerical values and the approximate symbolic expressions of poles and zeros of a circuit function is analyzed. At least for the given example, the numerical values obtained with this algorithm prove to be more accurate than those computed by HSPICE, SPECTRE and SAPWIN. The approximate symbolic pole expressions are also computed for this example. A comparison with known algorithms for the computation of the approximate pole/zero expressions as ANALOG INSYDES and SYMBA is performed. It follows that the symbolic LR algorithm, used in the proposed program, performs less drastic simplifications than the procedures used in ANALOG INSYDES and SYMBA. Difficulties arising in the computation of the approximate pole/zero expressions are discussed as well as some future developments in this area.