Improved LR algorithm for computation of the approximate symbolic pole/zero expressions

The following improvements are made to the symbolic LR algorithm for the computation of the approximate pole/zero expressions: formulation of the “state-like” matrix in the case d=0 in the output equation by the implementation of the Sandberg-So and Davison algorithms, using of matrices so that their diagonal elements are not placed in the decreasing order of their modules, replacing the search for the eigenvalue clusters with the elimination of one or two line and column pair during symbolic LR iterations. The zero symbolic expressions in term of transistor parameters for a LNA in the 900 MHz band illustrates these improvements. The proposed algorithm is similar or better with respect to the best ones implemented in ANALOG INSYDES and SYMBA software packages.