The (<i>p+q</i>)‐port transformer

Abstract Two approaches for realizing a ( p+q )‐port transformer using operational amplifiers are presented. Unlike iron‐core transformers, our realization is valid from d.c. to a relatively high frequency limited only by the op amp's frequency response. The stability and limitation of the two approaches are analysed and compared. Examples are given to illustrate two unique and indispensible applications of the ( p+q)‐port transformer : Synthesis of non‐linear n‐ports and non‐linear programming .