On the sufficiency of 2N operational amplifiers to realize an arbitraryN imes Nvoltage transfer matrix

A synthesis procedure is presented which proves the following theorem: For the realization of on arbitrary N X N matrix of real rational functions in the complex variable as a voltage transfer matrix of a transformerless grounded active RC 2N-port network, it is sufficient that the network contains 2N single-ended operational amplifiers embedded in an RC network.