An investigation into current possibilities in automated network design.

During the past decade, many techniques for computer-aided circuit design have been suggested and investigated, but none have been developed to the stage where the designer is redundant. The research described herein concerns the application of one technique, the method of coefficient matching, to the synthesis of lumped, linear, passive, 3-terminal networks with no mutual inductances. The author developed a program which, with further development, could perform the entire design process with no designer interaction. Further, the author considers problems where the classical synthesis methods are unsuitable, e.g. the synthesis of non-series-parallel networks with no series-parallel equivalent. The coefficient matching procedure is based on selecting a starting network which yields the correct polynomial structure and achieving a solution by component value adjustment and network evolution. The closer the starting network to a feasible topology, the more rapid the convergence to a solution. It is shown that the suitability of a starting network can be analysed on the basis of the information obtained from the different but equivalent forms of the admittance functions. The significance of common factors is discussed and the influence of various types of common factors on the network realization is investigated. For cases when the initial starting network is remote from any feasible solution, sophisticated techniques allowing substantial topological modification during network evolution are required. These techniques were developed by the author on the basis of element and node addition and elimination. A Fortran IV program has been developed by the author welding together all these aforementioned techniques for topological modification. The program makes large topological modification automatically during the design process. The effectiveness and efficiency of these techniques and the program are illustrated by a variety of synthesis examples.