M. Delasen, A METHOD FOR GENERAL DESIGN OF POSITIVE REAL FUNCTIONS, IEEE transactions on circuits and systems. 1, Fundamental theory andapplications, 45(7), 1998, pp. 764-769
The objective of this brief is to develop a general method for the syn
thesis of a solution to the problem of designing positive real functio
ns of a prefixed Hurwitz denominator polynomial. Such a synthesis prob
lem is reduced to the calculation of the solution of an equivalent alg
ebraic system of linear equations. The dual problem of designing the d
enominator polynomial for a prefixed given numerator polynomial is als
o focused on. The problem is first solved for rational realizable func
tions and extended in a natural way to nonrational ones by simply addi
tion of single derivative blocks of positive gain. The possibility tha
t common factors can appear ''a priori'' in the decomposition of the n
umerator polynomial in its real and imaginary parts is considered in t
he given synthesis procedure and it is then theoretically solved.