PANDDA: a program for advanced network design: digital and analogue

New design techniques and filter applications call for more advanced facilities to be offered to the designer. Important examples are: 1. the design of arbitrarily weighted frequency responses, 2. easy construction and comparison of many different filter structures, especially to allow new structures to compete with the popular, well-tested ones, 3. optimisation methods to improve the performance of circuits within physical constraints. These topics form the motivation for PANDDA, a new prototype filter design system. PANDDA is a highly modular program, with well-defined interfaces between the main stages, permitting convenient access at all levels. The software is distinguished by its use of iterative algorithms, providing good accuracy and efficiency while avoiding the complexity of traditional approaches. Special attention has been given to the problems of obtaining good initial values and convergency. Matrix methods are applied [6] as a compact and flexible approach to filter network derivation, greatly facilitating the incorporation of new designs. An optimisation procedure has been developed which makes use of the efficiency of the design process. The program will produce a network description for a number of the popular circuit simulation programs. An example of a practical filter design is given and optimisation of the circuit is illustrated