A new signal flowgraph formulation of symbolic network functions

Symbolic topological analysis of the closed primitive signal flowgraph corresponding to a linear active or passive network having an edge admittance matrix is considered. First, necessary and sufficient conditions for the occurence of term cancellation in Mason´s formula for the graph determinant are established. Then, a new signal flowgraph topological formula for the graph determinant in which no term cancellation occurs is proved. A computer program to implement the new formula is described. It is shown that this program is more efficient than existing programs based on Mason´s formula.