Flexible design method for active RC two-ports

It is shown that by the application of feedforward and feedback to the several nodes of an RC ladder network any required transfer function can be realized. The synthesis algorithm is basically simple. The tedious part of it is the evaluation of certain polynomials. These, however, are tabulated for those networks in common use. For any network the polynomials can be computed from recurrence relations obtained from the normalized admittance matrix of the network. The active elements employed are amplifiers. The design method is flexible, in that there is a choice of RC networks; at the expense of extra computation the number of active elements can be reduced, and other practical considerations allowed for; and the circuit details can be modified for applications as diverse as analogue computation or the construction of telephone filters.